|
Forward ;
Executive Summary ;
Chapter 1 - The Current
Situation
Chapter 2 - Pharmacological
Management
Chapter 3 - Neurobiology and Preclinical Research
Chapter 4 - Clinical Findings ;
Chapter 5 - Clinical Profile
Appendix A - Bibliography
; Appendix B - Naltrexone
and Formulary
Appendix C - Translating
Research Into Practice ;
Appendix D - Instruments
; Figures
The
Treatment Improvement Protocol (TIP) series fulfills SAMHSA/
CSAT's mission to improve treatment of substance use disorders
by providing best practices guidance to clinicians, program
administrators, and payers. TIPs are the result of careful
consideration of all relevant clinical and health services
research findings, demonstration experience, and implementation
requirements. A panel of non-Federal clinical researchers,
clinicians, program administrators, and patient advocates
debates and discusses their particular area of expertise until
they reach a consensus on best practices. This panel's work is
then reviewed and critiqued by field reviewers.
The talent, dedication, and hard work that TIPs panelists and
reviewers bring to this highly participatory process have
bridged the gap between the promise of research and the needs of
practicing clinicians and administrators. We are grateful to all
who have joined with us to contribute to advances in the
substance abuse treatment field.
Nelba
Chavez, Ph.D.
Administrator, Substance Abuse and Mental Health Services
Administration
Camille
T. Barry, Ph.D., R.N.
Acting Director, Center for Substance Abuse Treatment
Substance Abuse and Mental Health Services Administration
Psychosocial
treatments for alcoholism have been shown to increase abstinence
rates and improve the quality of life for many alcoholics.
Nonetheless, a significant proportion of alcoholics find it
difficult to maintain initial treatment gains and eventually
relapse to problematic drinking. Some of these individuals can
now be helped with naltrexone, an opiate antagonist recently
approved by the Food and Drug Administration (FDA) to treat
alcohol abuse disorders. When used as an adjunct to psychosocial
therapies for alcohol-dependent or alcohol-abusing patients,
naltrexone can reduce
-
The percentage of days spent drinking
-
The amount of alcohol consumed on a drinking occasion
-
Relapse to excessive and destructive drinking
This
TIP will help clinicians and treatment providers use naltrexone
safely and effectively to enhance patient care and improve
treatment outcomes.
Naltrexone therapy improves treatment outcomes when added to
other components of alcoholism treatment. For patients who are
motivated to take the medication, naltrexone is an important and
valuable tool. In many patients, a short regimen of naltrexone
will provide a critical period of sobriety, during which the
patient learns to stay sober without it.
The Consensus Panel that developed this Treatment Improvement
Protocol (TIP) made recommendations based on a combination of
clinical experience and research-based evidence. Their
guidelines are summarized below. Those supported by the research
literature are followed by (1); clinically based recommendations
are marked (2). Citations to the former are referenced in the
body of this document, where the guidelines are presented in
full detail.
Concurrent Psychosocial
Interventions
Naltrexone
has been approved as an adjunct to psychosocial treatment and
should not be seen as a replacement for psychosocial
interventions. Treatment is significantly more successful when
the patient is compliant with both the medication and
psychosocial programs. Psychosocial treatments are likely to
enhance compliance with pharmacotherapy, and likewise,
pharmacotherapies enhance psychosocial treatment by reducing
craving and helping the patient remain abstinent.
Pharmacological Management
Eligibility for Treatment
The
following details some of the criteria for determining patients'
eligibility for treatment with naltrexone:
-
Individuals who have been diagnosed as alcohol dependent,
are medically stable, and are not currently (or recently)
using opioids (e.g., heroin, controlled pain medication) are
suitable candidates for naltrexone therapy.
-
Individuals with acute hepatitis or liver failure are not
suitable candidates.
-
Patients requiring narcotic analgesia also are not
suitable candidates.
-
Appropriate candidates should be willing to be in a
supportive relationship with a health care provider or
support group to enhance treatment compliance and work
toward a common goal of sobriety.
-
Patient interest and willingness to take naltrexone are
important considerations.
-
At the currently recommended dose of 50 mg daily, hepatic
toxicity is very unlikely. Continued alcohol use is more
likely than naltrexone to cause liver damage. Before
determining a patient's eligibility for naltrexone therapy,
clinicians should be aware that alcohol alone may be
responsible for pretreatment elevated liver function test (LFT)
results. In some cases, simply stopping the consumption of
alcohol will immediately lower LFT values appreciably. When
there is a question, the Consensus Panel recommends
repeating LFTs after 5 to 7 days of abstinence. (2) If the
levels dramatically improve, then the patient may be a
suitable candidate for naltrexone.
-
Providers should perform LFTs prior to treatment
initiation and periodically during treatment. The Consensus
Panel recommends caution in using naltrexone with patients
whose serum aminotransferases results are five times above
normal. (1) Because total bilirubin reflects more severe and
potentially chronic liver dysfunction, the Consensus Panel
recommends using total bilirubin to both evaluate and
monitor the development of liver problems. Patients with an
elevation of total bilirubin should be referred to an
internist or hepatologist for a consultation prior to
considering naltrexone therapy.
-
The final decision to use naltrexone should be based on a
risk-benefit analysis. Clinician and patient may choose to
start naltrexone treatment in spite of the presence of
medical problems because the potential benefits of reducing
or eliminating alcohol consumption may outweigh the
potential risk of naltrexone.
Naltrexone and Other
Substances
The
use of other substances during naltrexone treatment,
particularly illegal opiates and opioid-containing medications,
may pose the same level of concern and possible adverse
consequences as the use of alcohol. Random urinalysis,
collateral reports from family members or employer (with the
patient's written consent), and self-reports from the patient
can be used to evaluate the use of other substances. In addition
to illegal substances, the use of both prescription and
nonprescription medications should also be addressed. The
patient's agreement or resistance to continuing treatment may
indicate his or her level of willingness to consider other
substance use as a problem.
Interactions with opiates
and opioids
Because
naltrexone may cause or worsen opiate withdrawal in subjects who
are physiologically dependent on opiates or who are in active
opiate withdrawal, it is contraindicated in these patients until
after they have been abstinent from opiates for at least 5 to 10
days, or longer if they are withdrawing from methadone without
benefit of buprenorphine (Buprenex) (once approved). (1)
Naltrexone is absolutely contraindicated in patients currently
maintained on methadone or LAAM (levo-alpha-acetyl-methadol) for
the treatment of opiate dependence. (1) Naltrexone does not
interfere with nonopioid pain medications such as ibuprofen,
acetaminophen, and aspirin. (1)
If at any time the need for opioid treatment becomes necessary,
naltrexone therapy can be discontinued for 2 or 3 days, and the
opioid can then be given in conventional doses. If opioids are
needed to reduce pain in someone with recent naltrexone
ingestion, pain relief can still be obtained but at higher than
usual doses. These doses require close medical monitoring. (2)
Patients should be warned that self-administration of high doses
of opiates while on naltrexone is extremely dangerous and can
lead to death from opioid intoxication by causing respiratory
arrest, coma, or circulatory collapse.
In emergency situations requiring opiate analgesia, a rapidly
acting analgesic with minimal respiratory depression should be
used and carefully titrated to the patient's responses.
Interactions with other
drugs
Caution
should be used when combining naltrexone with other drugs
associated with potential liver toxicity, such as acetaminophen
and disulfiram (Antabuse). Other interactions of which Consensus
Panel members are aware include thioridazine (Mellaril) and oral
hypoglycemics. The Consensus Panel recommends that clinicians be
aware of all of the patient's medications and watch closely for
naltrexone's interactions with other drugs. Clinicians should
report adverse drug-drug interactions to the manufacturer(s) if
they do occur. Concurrent use of antidepressants and naltrexone
appears to be safe.
Interaction with alcohol
Unlike
disulfiram, naltrexone does not appear to alter the absorption
or metabolism of alcohol and does not have major adverse effects
when combined with alcohol. Some patients, however, have noted
increased nausea caused by drinking alcohol while taking
naltrexone. Patients on naltrexone are less likely to relapse to
heavy drinking following a lapse in abstinence. However, both
patient and provider should know that naltrexone does not make
people "sober up" and does not alter alcohol's acute
effects on cognitive functioning.
Starting Treatment
Patient education comes
first
Patients
must be taught how naltrexone works and what to expect while
taking it. Treatment providers should tell patients that the
medication is not a "magic bullet"; instead,
naltrexone is likely to reduce the urge to drink and the risk of
returning to heavy drinking. Providers should negotiate a
treatment plan with the patient at each stage of therapy.
Initial medical workup
The
pretreatment medical workup should include
-
A complete physical examination, including the liver
-
Various laboratory tests, including LFTs (e.g., serum
aminotransferases, total bilirubin)
-
A pregnancy test
-
A urine toxicology screen
-
A complete/updated medical history to rule out possible
contraindications
-
A substance abuse history that focuses on the use of
other substances, especially opiates, as well as the
patient's history of use, misuse, or abuse of prescribed
medications
-
A mental health/psychiatric status screening
Positive
mental health/psychiatric screens may necessitate more formal
mental status examinations to determine the severity of the
illness and the appropriate course of treatment. The Consensus
Panel recommends focusing the psychiatric interview on anxiety
symptoms, depression, psychosis, and cognitive functioning
because these elements may complicate therapy. (1)
Pretreatment abstinence
Naltrexone
should be initiated after signs and symptoms of acute alcohol
withdrawal have subsided. The Consensus Panel recommends that
patients be abstinent for 3 to 7 days before initiating
naltrexone treatment. (2)
Starting doses
The
FDA has established guidelines for the dosage and administration
of naltrexone. Within general parameters, treatment with
naltrexone must be individualized according to these factors as
well as to the particular needs of each patient. The FDA
guidelines recommend an initiation and maintenance dose of 50
mg/day of naltrexone for most patients, usually supplied in a
single tablet. Because adverse events may make the patient
reluctant to continue the medication, the starting dose can be
reduced for several days or divided in two. (2) For example,
treatment can begin with either one-quarter of a tablet (12.5
mg/day) or one-half of a tablet (25 mg/day) daily, with food,
and eventually move to a full tablet daily (50 mg/day) within 1
to 2 weeks if tolerated.
Management of common
adverse effects
Common
adverse effects, which may include nausea, headache, dizziness,
fatigue, nervousness, insomnia, vomiting, and anxiety, occur at
the initiation of treatment in approximately 10 percent of
patients. The Consensus Panel recommends the following
strategies:
-
Patient education. If patients are going to experience
common adverse effects, these tend to occur early in
treatment, and the symptoms generally resolve within 1 to 2
weeks. Support and reassurance can help patients better
tolerate these transient adverse effects.
-
Timing of doses. The Consensus Panel recommends morning
dosing for most patients to establish a routine and ensure
better compliance. (1) Naltrexone should ideally be taken
after the "regular" morning routine, preferably
with food. Individual patient needs can also guide the
timing of doses.
-
Split dosage. If there is a need to split the dose, then
the patient should take half in the morning and half in the
evening, preferably with dinner.
-
Management of nausea. Nausea is a problem for
approximately 10 percent of patients and may reduce
compliance. To minimize nausea, patients can take naltrexone
with complex carbohydrates such as bagels or toast and not
take the medication on an empty stomach. (2) The use of
simethicone (e.g., Maalox) or bismuth subsalicylate (e.g.,
Pepto-Bismol) before taking naltrexone may help. Strategies
for controlling persistent nausea or other adverse events
include dose reduction, slow titration, and cessation of the
medication for 3 or 4 days and then reinitiating it at a
lower dose. (2)
-
Withdrawal. Patients may not be able to discriminate
between the common effects of withdrawal from alcohol and
the common adverse effects caused by naltrexone. Patients
should be reassured that their symptoms will get better with
time. Alcohol withdrawal can be managed with support or
benzodiazepines if indicated.
Ongoing Treatment With
Naltrexone
Maintenance doses
Low doses
Maintenance
doses of less than the standard 50 mg/day regimen may be
considered in patients who do not tolerate the standard
maintenance dose but who are otherwise good candidates for
naltrexone. It is preferable to decrease the maintenance dose to
25 mg/day to avoid noncompliance and relapse due to common
adverse effects rather than to rule out naltrexone as a
treatment option for these patients. Some patients may ask to
take naltrexone twice daily in order to experience subjective
relief from craving. In these cases, the daily dose may be
divided in two and given at those times of the day when craving
is strongest.
Higher doses
Under
certain circumstances, providers may increase the daily
naltrexone dose to greater than 50 mg. Patients who may be
considered for an increase include those who report persistent
feelings of craving, discomfort, and even brief relapses,
despite compliance with their treatment plan. In such cases,
dosages of 100 mg/day are sometimes used, with appropriate
medical monitoring. There is evidence that naltrexone is well
tolerated, safe, and efficacious at these higher doses.
Before adjusting dosage, providers should first consider
intensification of other treatment interventions, particularly
psychosocial components. The reason the medication is not
working should be explored. Providers should view a patient's
request for increased dose as a sign of engagement and
motivation in treatment, not as drug-seeking behavior. In some
outpatient treatment, higher doses of naltrexone have been given
under observation either 2 days a week or 3 days a week. If this
is necessary and the patient tolerates a higher dose, possible
protocols are 100 mg on Monday and Wednesday, with 150 mg on
Friday; 150 mg on Monday and 200 mg on Thursday; or 150 mg every
third day.
Duration of treatment
Although
FDA guidelines indicate that naltrexone should be used for up to
3 months to treat alcoholism, the Consensus Panel recommends
that treatment providers individualize the length of naltrexone
treatment according to each patient's needs. (2) Initially, the
patient can be treated with naltrexone for 3 to 6 months, after
which the patient and the therapist can reevaluate the patient's
progress. At this time, the decision to extend treatment must be
based on clinical judgment. The Consensus Panel concurs that
certain patients may be appropriate candidates for long-term
(e.g., up to 1 year) naltrexone treatment if they demonstrate
evidence of compliance with medication and psychosocial
treatment regimens. (2) Factors to be weighed in the clinical
decision to extend treatment beyond 3 to 6 months include
patient interest, recent dose adjustment, partial treatment
response, and prophylaxis in high-risk situations.
Other Clinical
Considerations During Treatment
Followup liver function
tests
After
the initial screening, followup LFTs should be completed after 1
month of naltrexone treatment. If the results are acceptable,
followup LFTs may then be conducted at 3 and 6 months after the
initiation of treatment, depending on the severity of liver
dysfunction at the start of treatment. More frequent monitoring
is indicated for cases in which dose adjustments are being made,
baseline LFTs are high, there is a history of hepatic disease,
disulfiram or other potential hepatic-toxic medication is added
to the treatment, or symptomatology indicates the need for
monitoring.
Pain management
Because
naltrexone blocks the effects of usual doses of therapeutic
opioids, providers should use nonnarcotic methods of analgesia
as first line of treatment for pain conditions. If narcotic pain
relief is indicated, patients must discontinue naltrexone use
for the period during which analgesics are required. If a
painful event such as surgery is anticipated, then naltrexone
should be discontinued 72 hours prior to the procedure. (1) If a
patient is taken off naltrexone and put on an opioid analgesic,
he or she should be abstinent from the narcotic for at least 3
to 5 days before resuming naltrexone treatment. (1)
In emergencies such as cases of acute severe pain, higher doses
of opioid analgesics may be used with extreme caution to
override the blockade produced by naltrexone. The narcotic dose
needs to be carefully titrated to achieve adequate pain relief
without oversedation or respiratory suppression. Both the dose
and the patient's vital signs (including respiratory rate, level
of awareness, and level of analgesia) must be closely monitored.
Respiratory assistance and support must be available, should
this be necessary. The Consensus Panel recommends that patients
on naltrexone always carry safety identification cards providing
information that the patient is receiving naltrexone and
instructions for treating patients in the event of an emergency.
Continued drinking
The
continued or periodic drinking of alcohol may not be a
sufficient reason to discontinue naltrexone: Some patients
respond to naltrexone treatment at first by reducing rather than
stopping their drinking. When a patient drinks during treatment,
the treatment provider should evaluate whether the patient is
taking his or her medication regularly and actively
participating in treatment. The intensity of care along with the
expectations placed on the patient may be increased. Dose
adjustments may also be indicated.
Abstinence should be a desired goal for the patient; however,
reductions in drinking may be an acceptable intermediate
outcome. Failure to maintain complete abstinence is not
necessarily a failure of treatment because there are many other
areas of a patient's life that can improve, such as job
performance, social relationships, and general physical health.
Use of naltrexone in
conjunction with disulfiram
The
concomitant use of two potentially hepatotoxic medications is
not ordinarily recommended unless the probable benefits outweigh
the known risks. If naltrexone is used with disulfiram, then
treatment providers should perform LFTs shortly after the
initiation of combined use. Providers should retest patients
every 2 weeks for 1 to 2 months and thereafter at regular
intervals, such as monthly. (2) Combination therapy with
disulfiram and naltrexone should not be used for very long
periods, and generally, the two drugs should not be started
simultaneously.
Ending Naltrexone Therapy
Successful termination of
naltrexone
Because
naltrexone is not addicting, patients who stop taking the
medication do not suffer from withdrawal symptoms, so naltrexone
therapy can be discontinued without tapering the dose.
Nonetheless, dose reductions may be psychologically useful to
the patient. The treatment team should work with the patient in
developing structured plans in the event of threatened or actual
relapse. Scheduled followup visits ("booster visits")
may also be helpful in providing support for the patient and
opportunities for intervention based on identifying early signs
of potential relapse. Naltrexone may be restarted if the patient
and the treating clinicians feel that it may be helpful in
preventing relapse.
Monitoring the outcome of
treatment
In
evaluating the outcome of naltrexone therapy, providers should
expect to see evidence of positive improvement over time as
evaluated by the treatment program's indicators of progress.
Some of the possible criteria that can be used and selected to
fit each program's needs and policies include
-
Compliance with treatment plan
-
Stable abstinence or significant reduction in the
frequency and amount of drinking, as indicated by patient
self-reports, collateral reports, and biological markers
-
Markedly diminished craving
-
Improvement in quality of life, including physical and
mental health status, family and social relationships, work
and/or vocational status, and legal status
-
Abstinence from other substances of abuse
Other Topics
This
TIP reviews the basic neurobiological and preclinical research
supporting clinical investigations of naltrexone for treatment
of alcohol dependence. An overview of neurological reinforcement
systems and drug dependence for providers who do not have a
medical background explains how naltrexone works.
Also reviewed are the specific findings of the initial two
clinical trials that established the efficacy of naltrexone in
the treatment of alcohol dependence. This document describes the
subsequent research to identify the patients most likely to
benefit from naltrexone treatment, the differential subjective
effects of naltrexone, the use of naltrexone for other patient
populations, naltrexone in the context of other
pharmacotherapies, and directions for future research.
The TIP provides a brief overview of naltrexone as a medication,
including its development and clinical role, its mechanism of
action, its pharmacokinetic properties, its safety and common
adverse effects, and some clinical considerations when
prescribing this medication.
Appendix
B guides clinicians and administrators who are
interested in adding naltrexone to the formulary of their health
care organization. Included in this appendix is an extensive
list of Federal and private Web sites for readers who may want
to access additional information about substance abuse treatment
through the Internet. Appendix
C details the process by which innovations are
adopted over time and outlines strategies that encourage
technology transfer and research utilization. For the
organization that would like to incorporate naltrexone as a
potential treatment adjunct, this appendix offers suggestions
about how to prepare the system for this change. Finally, Appendix
D provides two instruments to help treatment
providers who would like to monitor craving in their patients:
The Obsessive Compulsive Drinking Scale and the Alcohol Urge
Questionnaire.
This TIP will give treatment providers the information they
need, first to determine which patients can benefit from
naltrexone and second to safely and effectively administer the
medication. Although research on the use of naltrexone for
alcohol abuse disorders is ongoing, this TIP presents the
"state of the art" from the country's leading experts
on this important advance in substance abuse treatment.
Some
9.6 percent of men and 3.2 percent of women in the United States
will become alcohol dependent at some time in their lives (Grant, 1992).
The most recent National Household Survey on Drug Abuse
estimates that about 32 million Americans had engaged in binge
or heavy drinking (five or more drinks on the same occasion at
least once in the previous month) and that about 11 million
Americans were heavy drinkers (five or more drinks on the same
occasion on at least five different days in the past month) (Substance Abuse and Mental
Health Services Administration [SAMHSA], Office of Applied
Studies, 1996). Alcohol-related disorders occur in up
to 26 percent of general medical clinic patients, a prevalence
rate similar to those for other chronic diseases such as
hypertension and diabetes (Fleming and Barry, 1992).
Alcoholics consume more than 15 percent of the national health
care budget (Rice et al., 1990),
seeking attention in medical settings for various secondary
health problems (Schurman et al., 1985).
Researchers calculate that about 18 million Americans with
alcohol abuse problems need treatment, but only one-fourth of
them receive it (Institute for Health Policy,
1993; Institute of Medicine, 1996).
People suffering from alcohol disorders include teenagers,
women, men, the employed or the unemployed, alone and isolated
or part of a family, homeless or financially secure, and people
of every race, creed, and level of education. People who have
mental illness have a higher rate of substance abuse and
alcoholism than everyone else; they also have a harder time
getting help and staying in treatment. Recent tests on the
medication naltrexone indicate that this drug can help many of
those people. Naltrexone has been proven to decrease problem
drinking--in some cases by almost half--when used with existing
treatments, compared with other treatments used alone (O'Malley et al., 1992;
Volpicelli et al., 1992,
1997).
The Evolution of Treatment
Today,
alcoholism treatment generally consists of medical,
psychological, and social interventions to reduce or eliminate
the harmful effects of alcohol dependence and abuse on the
individual, his or her family and associates, and others in
society. Treatment approaches range from lower cost, less
intensive methods (e.g., brief interventions/advice to stop or
reduce drinking, referral to self-help programs) to higher cost,
more intensive methods (e.g., inpatient detoxification and
rehabilitation programs, residential treatment).
Many different orientations toward treatment, such as 12-Step,
behavioral, motivational, medical, and spiritual, are used to
various extents by treatment programs. A patient may need a
different type of treatment at different stages in his or her
life and in different phases of his or her addiction. There is
no perfect way to treat every person, but research is under way
to determine how to choose and apply the most appropriate
treatment specifically to the particular needs of each patient.
Although the stigma attached to alcohol problems has abated,
many still believe that alcohol problems represent a moral
failing and that an alcoholic should be able to
"white-knuckle" his or her way to sobriety. Such
biases can be held by the patients themselves, by treatment
providers with different backgrounds, by insurers, by
communities, and by the legal establishment regionally. Those
biases about the best way to treat substance abuse and
dependence sometimes prevent patients from receiving adequate
and appropriate care.
Understanding that the abuse of alcohol and other substances
causes profound changes in brain chemistry and function may help
to reduce the stigma and shame surrounding repeated relapse to
alcohol abuse. Continued education and understanding should
reduce the bias against the use of medications to treat the
illness of substance abuse and dependence. As scientists
continue mapping the brain, particularly those areas that govern
pleasure and addiction, pharmacotherapies such as naltrexone
will likely be used more often.
Development and Current Use
of Naltrexone
Naltrexone
was initially developed for the treatment of narcotic or opioid
addiction, including heroin, morphine, and oxycodone (e.g.,
Percocet). Naltrexone is an opioid antagonist, which means that
it blocks the effects of opioids. During the 1980s, animal
studies revealed that opioid antagonists, including naltrexone,
which the FDA approved in 1984 for treating opiate addiction,
also decreased alcohol consumption by blocking certain opioid
receptors (i.e., action sites) in the brain that help to
maintain drinking behavior. Building on those laboratory
findings, researchers conducted human clinical trials to
determine whether naltrexone could play a role in the treatment
of alcoholism (O'Malley et al., 1992;
Volpicelli et al., 1992).
The results of these studies suggest that naltrexone, when
combined with appropriate psychosocial therapy, can effectively
reduce craving and relapse rates in general populations of
alcohol-dependent patients (Volpicelli, 1995).
Based on such findings, the FDA approved naltrexone for use in
the treatment of alcoholism.
Psychosocial treatments for alcoholism have been shown to
increase abstinence rates and improve the quality of life for
many alcoholics (Miller
and Hester, 1986). Nonetheless, a significant
proportion of alcoholics find it difficult to maintain initial
treatment gains and eventually relapse to problematic drinking.
When used as an adjunct to psychosocial therapies for
alcohol-dependent or alcohol-abusing patients, naltrexone can
reduce
-
The percentage of days spent drinking
-
The amount of alcohol consumed on a drinking occasion
-
Relapse to excessive and destructive drinking
The
National Institute on Alcohol Abuse and Alcoholism is currently
funding over a dozen clinical trials with naltrexone, and a
large-scale multisite study of naltrexone in combination with
12-Step facilitation therapy is being funded through the
Department of Veterans Affairs.
Overview
The
Consensus Panel that developed this TIP includes the country's
leading experts on naltrexone. The Panel's aim is to provide
counselors, treatment providers, clinicians, and the general
public with a responsible, understandable assessment of the
current data on the effectiveness and use of naltrexone for the
treatment of alcoholism and alcohol abuse. Members of the Panel
have drawn on the published literature, study findings that have
been presented at conferences, and on their considerable
clinical experience.
Chapter 2 is a
"how to" chapter that covers the important clinical
issues in using naltrexone as an adjunct to treatment. These
issues include a review of eligibility considerations for
naltrexone treatment, the initiation of treatment, ongoing
treatment, and treatment termination issues. Chapter 3 details
the basic neurobiological and preclinical research supporting
clinical investigations of naltrexone for treatment of alcohol
dependence. An overview of neurological reinforcement systems
and drug dependence explains how naltrexone works. Chapter
4 describes the specific findings of the initial two
clinical trials (O'Malley et al., 1992;
Volpicelli et al., 1992)
that established the efficacy of naltrexone in the treatment of
alcohol dependence. It also describes subsequent research to
identify the patients most likely to benefit from naltrexone
treatment, the differential subjective effects of naltrexone,
the use of naltrexone for other patient populations, naltrexone
in the context of other pharmacotherapies, and directions for
future research. Chapter
5 provides a brief overview of naltrexone as a
medication, including its development and clinical role, its
mechanism of action, its pharmacokinetic properties, its safety
and common adverse effects, and some clinical considerations
when prescribing this medication.
The bibliography for this TIP appears in Appendix
A. Appendix
B guides clinicians or administrators who are
interested in adding naltrexone to the formulary of their health
care organization. Included in this appendix is an extensive
list of Federal and private World Wide Web sites for readers who
may want to access additional information about substance abuse
treatment through the Internet. Appendix
C details the process by which innovations are
adopted over time and outlines strategies that encourage
technology transfer and research utilization. For the
organization that would like to incorporate naltrexone as a
potential treatment adjunct, this appendix offers suggestions on
how to prepare the system for this change. Appendix
D provides two instruments to help treatment
providers: The Obsessive Compulsive Drinking Scale and the
Alcohol Urge Questionnaire.
It is important to remember that naltrexone may not be effective
for every person with alcohol abuse disorder. In combination
with other therapies, however, it can greatly improve outcomes
for certain individuals. This TIP will help providers use
naltrexone safely and effectively to enhance patient care and
improve treatment outcomes.
Naltrexone
therapy improves treatment outcomes when added to other
components of alcoholism treatment. Treatment providers should
tell patients that the medication is not a "magic
bullet"; instead, naltrexone is likely to reduce the urge
to drink and the risk of a return to heavy drinking. For
patients who are motivated to take the medication, naltrexone is
an important and valuable tool. In many patients, a limited
period of naltrexone will assist in providing a critical period
of sobriety, while the patient learns to stay sober without it.
When starting naltrexone therapy, the treatment provider should
consider eligibility, dosing strategies, medical considerations,
ongoing monitoring, concurrent psychosocial intervention, and
needs of special populations.
Naltrexone has few, if any, intrinsic actions besides its
opioid-blocking properties: It does not block the physiological
or psychological effects of any other class of drug. Because
alcohol, like opiates, stimulates opioid receptor activity,
naltrexone also appears to reduce the reinforcing/rewarding
"high" that usually accompanies drinking. With the
reduction in euphoria, alcohol consumption seems to be less
rewarding. This may be one reason naltrexone works.
Eligibility for Treatment
Suitable Candidates
Naltrexone
therapy is approved by the Food and Drug Administration (FDA)
for use in individuals who have been diagnosed as alcohol
dependent, are medically stable, and are not currently (or
recently) using opioids (e.g., heroin, controlled pain
medication). Because naltrexone is an addition to psychosocial
support, appropriate candidates should also be willing to be in
a supportive relationship with a health care provider or support
group to enhance treatment compliance and work toward a common
goal of sobriety.
Although it is not yet known who will succeed or who will fail
when treated in this way, some studies suggest that those
patients with high levels of craving, poor cognitive abilities,
little education, or high levels of physical and emotional
distress may derive particular benefit from the addition of
naltrexone therapy to their psychosocial treatment (Jaffe
et al., 1996; Volpicelli
et al., 1995a). These are patients who often fail
psychosocial treatments. Other factors such as family history of
alcoholism and motivational status are unproven predictors of
outcome but are currently being studied. Clearly, patient
interest and willingness to take naltrexone are likely to be
important considerations. Patients who have taken naltrexone
before and quit because of nausea or headaches may be afraid to
try it again. This is an opportunity for the treatment team to
support and encourage the patient and to try a reduced-dose
taper onto the drug.
Concurrent Psychosocial
Interventions Are Necessary
Naltrexone
has been approved as an adjunct to psychosocial treatment and
should not be seen as a replacement of psychosocial
interventions. Treatment is significantly more successful when
the patient is compliant with both the medication and
psychosocial programs (Volpicelli
et al., 1997). Indeed, the efficacy of naltrexone in
the absence of therapy has not been studied. The use of therapy
and naltrexone treatment in the same patient is not
contradictory, and in fact, there is a potential for synergy.
Psychosocial treatments are likely to enhance compliance with
pharmacotherapy; likewise, pharmacotherapies, to the extent to
which they reduce craving and help maintain abstinence, may make
the patient more available for psychosocial interventions.
Barriers to Treatment and
to Combination Treatment
The
Consensus Panel acknowledges that there is much resistance to
pharmacotherapy--from third-party payers, some addiction
clinicians, and some self-help-oriented individuals who view
medications as substituting a pill for self-empowerment and
taking responsibility for the disease.
There are many reasons to believe that naltrexone is compatible
with a range of psychosocial treatments for alcohol dependence,
including 12-Step programs. Self-help groups support the use of
nonaddicting medications in certain situations--it is important
to emphasize that naltrexone is not addicting. In a multisite
naltrexone safety study (DuPont
Pharma, 1995), participation in community support
groups was linked to good outcomes among patients receiving
naltrexone. In completed or ongoing research, naltrexone has
been used successfully as an adjunct to day hospital treatment,
supportive psychotherapy, cognitive behavioral relapse
prevention therapy, primary care counseling, and 12-Step
facilitation therapy.
Some consider the cost of naltrexone a barrier. Naltrexone costs
approximately $4.50 per day or $400 for a 3-month period.
Additional costs include followup liver function tests (LFTs).
In settings where patients do not routinely get physical
examinations, the costs of these examinations will be added to
the treatment costs. The daily cost of naltrexone, however, may
be less than the cost of alcohol used by most patients,
depending on which of the above costs are incurred by the
patient.
However, for some alcoholism treatment programs that cover the
costs of care for patients, these new costs may be difficult to
absorb. On the other hand, there may be cost offsets in
integrated systems, such as managed care systems or some
hospitals. For example, if naltrexone reduces the risk of
alcohol relapse, savings may occur in other medical costs
associated with continued alcohol use such as detoxification
services, poorly controlled hypertension due to medication
noncompliance, and emergency room visits for alcohol-related
injuries. For the individual, reduced alcohol consumption may
result in an improved quality of life, as well as improvements
in other areas including physical health, mental health, family
and social relationships, and job performance. For the employer,
cost offsets may result in fewer on-the-job problems and less
absenteeism by employees who benefit from treatment. At this
time, however, these potential cost offsets can only be proposed
because formal cost-effectiveness studies have not yet been
completed.
Importance of the Primary
Care Physician
In
primary care settings, large numbers of untreated individuals
with the diagnosis of alcohol dependence may benefit from
naltrexone therapy. Sixty percent of patients who are alcohol
dependent will come to a primary care provider's office in a
6-month period for other reasons (Shapiro et al., 1984).
These patients represent an untapped reservoir of individuals
who are not receiving needed treatment and who may be more
readily treated in the primary care setting. Brief advice and
monitoring by primary care providers can be effective in
motivating problematic drinkers to reduce excessive drinking (for a review, see Bien et
al., 1993). In compliant patients, the use of
naltrexone is likely to enhance treatment outcome. The primary
care provider may partner with other caregivers such as
psychologists (Bray and Rogers, 1995).
Figure
2-1 provides specific information on naltrexone for
the primary health care provider.
Contraindications: Relative
And Absolute
A
contraindication for taking a prescribed medication is any
symptom, circumstance, or condition that renders the medication
undesirable or improper, usually because of risk.
There are two types of contraindications for naltrexone:
Absolute contraindications, which refer to symptoms,
circumstances, or conditions for which naltrexone
unconditionally must not be prescribed, and relative
contraindications, which refer to symptoms, circumstances, or
conditions with varying degrees of risk that may preclude the
administration of naltrexone.
Here is a common question: Significant liver disease is a
relative contraindication to the use of other medications that
may cause liver damage; but many alcoholics already have liver
disease--can naltrexone still be used?
The answer is this: Because of the toxicity associated with
alcohol, liver abnormalities are common among alcohol-dependent
patients (Gonzalez and Brogden,
1988). Although initial blood tests may indicate some
hepatic (i.e., liver) dysfunction and therefore potential risk,
reductions in drinking resulting from treatment combining
naltrexone therapy may lead to improved liver function. Even so,
LFTs should be performed regularly to ensure that no damage is
being done and to guide clinical care. Similarly, many patients
who will benefit from naltrexone treatment have chronic
hepatitis B and/or hepatitis C; a controlled, randomized,
prospective study of such hepatitis patients showed no
significant difference in LFT results with naltrexone at the
recommended doses (Lozano Polo et al., 1997).
Another question is what to do when circumstances arise in
patients already taking naltrexone that would put the patient at
risk for harm if naltrexone treatment is continued. These
circumstances might include, for example, pregnancy or new
infection with viral hepatitis. Individuals who acquire new
relative or absolute contraindications should stop taking
naltrexone and be reevaluated. Figure
2-2 provides a list of absolute and relative
contraindications for naltrexone.
Naltrexone and the liver
Although
naltrexone has few absolute contraindications, high doses of
naltrexone (300 mg/day) may lead to elevations in serum
bilirubin and liver enzymes (e.g., Gonzalez and Brogden, 1988;
Sax et al., 1994)
. For this reason, the medication is contraindicated for
patients with acute infectious hepatitis or patients with liver
failure. (For a review of clinical studies on naltrexone and
liver damage, see Chapter 5.)
The Consensus Panel recommends caution in using naltrexone in
patients whose serum aminotransferases results are over three
times normal. In these patients, more frequent monitoring of
LFTs should be considered. In general, improvements in liver
function are expected if the patient responds to therapy and
maintains abstinence. Physicians experienced in the use of
naltrexone have given it safely to patients with significantly
elevated serum aminotransferases. Because total bilirubin
reflects more severe and potentially chronic liver dysfunction,
the Consensus Panel recommends using total bilirubin to both
evaluate and monitor the development of liver problems. A
hepatologist may be consulted prior to beginning naltrexone
therapy in patients with elevated total bilirubin.
Another issue clinicians should consider before determining a
patient's eligibility for naltrexone therapy is that alcohol
alone may be responsible for pretreatment elevated LFT results.
In some cases, simply stopping the consumption of alcohol will
immediately lower LFT values appreciably. When there is a
question, the Consensus Panel recommends repeating LFTs after 5
to 7 days of abstinence. If the levels dramatically improve,
then the patient may prove to be a suitable candidate for
naltrexone. Research supports this observation: In a number of
the treatment studies, LFTs in the group receiving naltrexone
improved over those not receiving naltrexone, presumably because
of the reduction in their drinking (O'Malley et al., 1992;
Volpicelli et al., 1992,
1995a, 1997).
As with many disorders, the final decision to use naltrexone
should be based on a risk-benefit analysis. Clinician and
patient may choose to start naltrexone treatment in spite of the
presence of medical problems because the potential benefits of
reducing or eliminating alcohol consumption may outweigh the
potential risk of naltrexone.
When the patient uses pain
medication or heroin
It
is important to focus not just on alcohol use but also to
address the use of other substances--particularly illegal
opiates and opioid-containing medications--that may pose the
same level of concern and possible adverse consequences. The use
of other substances can be evaluated by random urinalysis,
collateral reports from family members or employer (with the
patient's written consent), and self-reports from the patient.
In addition to illegal substances, the use of both prescription
and nonprescription medications is an important issue and should
also be addressed. In this regard, the patient's agreement or
resistance to continuing treatment may indicate his or her level
of willingness to consider other substance use as a problem.
Because of its opiate antagonist properties, naltrexone may
cause or worsen opiate withdrawal in subjects who are
physiologically dependent on opiates or who are in active opiate
withdrawal. Thus, naltrexone is contraindicated in these
patients until after they have been withdrawn from opiates for
at least 5 to 10 days, or longer if they are withdrawing from
methadone without benefit of buprenorphine (Buprenex) (once
approved). (Naltrexone is sometimes used with clonidine and
close medical monitoring as an opiate withdrawal method; see
O'Connor and Kosten, 1998, for a review). Similarly, naltrexone
is absolutely contraindicated in patients currently maintained
on methadone or LAAM for the treatment of opiate dependence.
Although the anticipated need for opioid medications on the
basis of an identified medical problem is a relative
contraindication for the use of naltrexone, it will not always
preclude the use of naltrexone by someone struggling to stop
drinking. Rather, particularly for chronic pain disorders, a
reduction in abusive drinking may help reduce pain and
disability and obviate the need for opioid analgesics.
If at any time the need for opioid treatment becomes necessary,
naltrexone therapy can be discontinued for 2 or 3 days, and the
opioid can then be given in conventional doses. If opioids are
needed to reduce pain in someone with recent naltrexone
ingestion, pain relief can still be obtained but at higher than
usual doses. These doses require close medical monitoring (see
the section on pain management later in this chapter).
The opioid blockade produced by naltrexone is not immediately
reversible but is potentially surmountable by very high doses of
opiates. Patients should be warned that self-administration of
high doses of opiates while on naltrexone is extremely dangerous
and can lead to death from opioid intoxication by causing
respiratory arrest, coma, or circulatory collapse. In emergency
situations requiring opiate analgesia, a rapidly acting
analgesic with minimal respiratory depression should be used and
carefully titrated to the patient's responses.
Pregnancy
Women
should be tested for pregnancy before initiating naltrexone and
advised to use a reliable form of birth control. Data on the use
of naltrexone during pregnancy are so scant that the risks are
basically unknown. In laboratory animals, naltrexone has been
shown to have an embryocidal effect when given in extremely high
doses (approximately 140 times the human therapeutic dose).
Consequently, naltrexone is classified by the FDA as a Category
C drug, which denotes
There are no adequate and well-controlled studies in pregnant
women. reVia [naltrexone] should be used in pregnancy only when
the potential benefit justifies the potential risk to the fetus (Physicians' Desk Reference
[PDR], 1997, p. 958).
Naltrexone has been shown to have effects on a number of
hormones, including growth hormone, luteinizing hormone, and
prolactin. In light of these effects, the Consensus Panel
generally recommends against the use of naltrexone during
pregnancy or while mothers are nursing their babies. The risks
of fetal alcohol syndrome (FAS) and other alcohol-related birth
defects are high for the offspring of women who continue to
abuse alcohol. Therefore, it is essential that the pregnant
patient receive treatment in one of the many excellent programs
available and maintain his or her sobriety to protect the health
and future well-being of her fetus. (More information is
available from the Centers for Disease Control and Prevention,
FAS Prevention Section, 770-488-7370, or e-mail at ncehinfo@cdc.gov.)
Adolescents
The
use of naltrexone in adolescents is considered a relative
contraindication because there are no data available about the
safety and efficacy of naltrexone in this population: Naltrexone
has been mostly studied in individuals 18 years of age and
older. The known effects of naltrexone on the human hormonal
system--including growth hormone, luteinizing hormone, and
prolactin-- are particularly important considerations in
adolescents because they have not reached full maturity. As a
result, naltrexone is not recommended for children who have not
reached puberty, and careful consideration of the potential
benefits and risks should be given prior to using naltrexone in
postpubescent individuals.
Naltrexone and Other
Substances
Drug-drug interactions
With
the exception of opiate-containing medications, formal drug
interaction studies have not been done. However, caution should
be used when combining naltrexone with other drugs associated
with potential liver toxicity, such as acetaminophen and
disulfiram (Antabuse). Other interactions of which Consensus
Panel members are aware include thioridazine (Mellaril; based on
case reports of oversedation) and oral hypoglycemics (based on
case report data). The Consensus Panel suggests that clinicians
be watchful of drug-drug interactions and report them to the
manufacturer(s) if they do occur. Based on the results of a
large multisite safety study recently conducted by the
manufacturer (Croop et al., 1997),
concurrent use of antidepressants and naltrexone appears to be
safe.
Interaction with alcohol
Unlike
disulfiram, naltrexone does not appear to alter the absorption
or metabolism of alcohol and does not have major adverse effects
when combined with alcohol. Some patients, however, have noted
increased nausea caused by drinking alcohol while taking
naltrexone. There is good evidence that naltrexone reduces the
likelihood of continued drinking following a lapse and decreases
the amount of alcohol consumed if there is a "slip"
during treatment. However, naltrexone does not make people
"sober up" and does not alter the acute effects of
alcohol on cognitive functioning (Swift et al., 1994).
Starting Treatment
Patient Education Comes
First
When
starting a new medication, the patient needs to understand how
it works and what to expect while taking it. Particularly with
naltrexone, treatment providers need to offer that information
and guidance to patients. Pamphlets for patients and providers
as well as copies of research reports on naltrexone can be
requested free of charge from DuPont Merck (1-800-4PHARMA), the
company that currently markets naltrexone (under the trade name
ReVia®).
The provider should negotiate a treatment plan with the patient
at each stage of therapy. Patients need to know that they may
experience protracted effects from their alcohol use and from
alcohol withdrawal, and that they may not feel well for some
period of time. They should understand that symptoms from
alcohol withdrawal are similar to common adverse effects from
naltrexone administration, and thus it is often difficult to
determine which symptoms are caused by naltrexone. When patients
do not feel well, it is a challenge to keep them in treatment.
Providers should educate patients so they can better manage
their own concerns and anxieties.
Most patients are willing to take naltrexone if they believe it
works. This has implications for provider education as well: If
alcoholism treatment clinicians and counselors do not believe
the medication is effective, then they can hardly be expected to
provide a convincing education for the patient. All clinicians
should have access to accurate information concerning naltrexone
treatment. This TIP provides such information and is free to
anyone who requests it.
Initial Medical Workup
An
initial medical workup must be completed before naltrexone
treatment can begin. The pretreatment workup should include a
physical examination, laboratory tests, medical and substance
use/abuse histories, and a mental health/psychiatric status
screen. A physical examination of the liver and various
laboratory tests, including LFTs, pregnancy test, and urine
toxicology screen, are also part of the medical workup. A
complete/updated medical history helps to rule out possible
contraindications. A substance abuse history should focus on the
use of other substances, especially opiates, as well as the
patient's history of use, misuse, or abuse of prescribed
medications. Screening for signs and symptoms of substance use
provides an added check to the substance abuse history and
results of the urine toxicology screen. For example, intravenous
use is associated with needle marks; hard blackened veins; and
abscesses in the arms, hips, buttocks, thighs, or calves.
Inhaled drugs often cause a brown tongue, nasal septum
abnormalities, or unexplained diffuse wheezes. Illicit drug use
can lead to unexplained severe constipation, agitation, repeated
requests for prescriptions for controlled substances, and a
desperate need to leave the office after several hours.
The presence of co-occurring mental disorders with alcohol
dependence may negatively influence the outcome of alcoholism
treatment if the coexisting mental disorders are not adequately
treated. Therefore, a mental health/psychiatric status screening
should also be part of the pretreatment workup. Positive screens
may necessitate more formal mental status examinations to
determine the severity of the illness and the appropriate course
of treatment. The Consensus Panel recommends focusing the
psychiatric interview on anxiety symptoms, depression,
psychosis, and cognitive functioning because these elements may
complicate therapy. Figure
2-3 summarizes the elements of a pretreatment workup.
The literature accompanying naltrexone suggests the use of a
naloxone (Narcan) injection challenge test in patients for whom
continued opioid use is suspected but not proven. This challenge
test is easily performed in the office by administering
subcutaneously 0.1 mg of naloxone and monitoring the patient for
withdrawal symptoms, including sweating, nausea, cramps,
vomiting, extreme discomfort, runny eyes and nose, and so on. If
no symptoms are seen within 5 minutes, then the test is negative
and naltrexone may be given orally. The Consensus Panel,
however, believes that the use of this test is usually not
necessary for alcohol-dependent patients--in most cases, a
careful patient history asking directly about opioid use
(including pills, snorting, and smoking recreationally) and a
urine toxicology screen for opioids is sufficient.
The Consensus Panel suggests that while gathering patient
history, providers and counselors should evaluate potential
constraints to honesty: A patient may not tell the truth if a
parent, spouse, or probation officer is present. On the other
hand, a family member may be able and willing to provide more
accurate and honest information about a patient's history.
Pretreatment Abstinence
Naltrexone
should be initiated after signs and symptoms of acute alcohol
withdrawal have subsided. However, no formal studies have
examined the effect of giving naltrexone during acute alcohol
withdrawal. Until more definitive information on this issue is
available, the Consensus Panel recommends that patients be
abstinent for 3 to 7 days before initiating naltrexone
treatment. The shorter time frame is designed to accommodate
standard 3-day detoxification programs. Studies to date have
shown naltrexone's effectiveness only among patients with at
least 5 days of abstinence, although naltrexone has been used in
patients who are actively drinking.
Initiation of abstinence can be accomplished in a variety of
settings. However, providers should follow standard protocols
for alcohol detoxification, including the use of the usual
medications as needed, vitamins, and monitoring for alcohol
withdrawal to prevent delirium tremens, seizures, and Wernicke's
encephalitis. The American Society of Addiction Medicine's
Patient Placement Criteria for the Treatment of
Substance-Related Disorders, Second Edition (American Society of
Addiction Medicine, 1996), and TIP 19, Detoxification
from Alcohol and Other Drugs (Center
for Substance Abuse Treatment [CSAT], 1995), provide
detailed information about matching patients to appropriate
levels of care, as well as step-by-step clinical detoxification
guidelines.
Starting Doses
The
FDA has established guidelines for the dosage and administration
of naltrexone. The use of naltrexone in actual clinical
practice, however, is in an evolving state and continues to be
tested and modified by treatment providers. Factors influencing
how and when naltrexone is used include the patient population
being treated, the severity of alcohol dependence, and the
requirements of the institutional system in which treatment
takes place. Within general parameters, treatment with
naltrexone must be individualized according to these factors as
well as to the particular needs of each patient.
The FDA guidelines recommend an initiation and maintenance dose
of 50 mg/day of naltrexone for most patients, usually supplied
in a single tablet (see PDR, 1997).
Although patients generally tolerate the drug well at this dose,
approximately 1 in 10 patients will experience nausea or
headache. Preliminary evidence indicates that certain
patients--such as women, younger patients, and those who have
had a short duration of abstinence before treatment
initiation--may experience a somewhat higher rate of nausea with
naltrexone treatment (O'Malley et al., 1996c).
Adverse events may make the patient reluctant to continue the
medication.
In practice, the starting dose is often reduced for several days
or divided in two, to prevent initial nausea and other adverse
events that sometimes occur. For example, treatment can begin
with either one-quarter of a tablet (12.5 mg/day) or one-half of
a tablet (25 mg/day) daily, with food, and eventually move to a
full tablet daily (50 mg/day) within 1 to 2 weeks if tolerated.
The brief period of abstinence prior to beginning naltrexone may
also help reduce the risk of adverse effects. Of course, if
significant adverse effects occur after an initial dose, lower
doses should be tried after a rest period of a few days. These
suggestions for dosing strategies are summarized in Figure
2-4.
Management of Common
Adverse Effects
In
a recent large multisite safety study (Croop et al., 1997),
the following individual adverse events were reported by 2 to 10
percent of the patients: nausea, headache, dizziness, fatigue,
nervousness, insomnia, vomiting, and anxiety (see Chapter 5 for
more details of this study). Because these adverse effects are
generally brief in duration and uncomfortable but not harmful,
management always includes giving patients coping strategies and
focusing on the positive aspects of naltrexone treatment.
Education prior to starting naltrexone is helpful, with the
caution that some patients are already afraid, anxious, and
susceptible to suggestion. Many of the common adverse
effects--notably headaches, nausea, and anxiety--may overlap
with symptoms experienced during alcohol withdrawal, so that it
is often difficult to assess whether the effects are due to the
medication or to the underlying withdrawal.
The Consensus Panel recommends the following strategies that
providers can implement to reduce common adverse effects:
-
Patient education. If patients are going to experience
common adverse effects, these tend to occur early in
treatment, and the symptoms generally resolve within 1 to 2
weeks. Support and reassurance can help patients better
tolerate these transient adverse effects.
-
Timing of doses. Because common adverse effects may
worsen during nicotine withdrawal, patients who smoke should
not take naltrexone immediately after waking up. For all
patients, naltrexone should ideally be taken after the
"regular" morning routine, preferably around
breakfast time with food. Individual patient needs can guide
the timing of doses: Fatigue suggests an evening dose,
whereas sleeplessness suggests a morning dose.
-
Split dosage. The Consensus Panel recommends morning
dosing for most patients in order to establish a routine and
ensure better compliance. However, if there is a need to
split the dose, then it will be important to help the
patient establish a good routine for dosing later in the
day, especially if the patient is not in stable housing. One
simple way is to take half a pill with breakfast, and then
take the second half with dinner.
-
Dose reduction. Strategies for controlling persistent
nausea or other adverse events include dose reduction, slow
titration, and cessation of the medication for 3 or 4 days
and then reinitiating it at a lower dose.
-
Management of nausea. Nausea is a problem for
approximately 10 percent of patients and may reduce
compliance. To minimize nausea, patients should be advised
to take naltrexone with complex carbohydrates such as bagels
or toast and not to take the medication on an empty stomach.
The use of a tablespoon of simethicone (e.g., Maalox) or
bismuth subsalicylate (e.g., Pepto-Bismol) before taking
naltrexone may help. Dose reductions as described above
should also be considered.
-
Withdrawal. Patients may not be able to discriminate
between the common effects of withdrawal from alcohol and
the common adverse effects caused by naltrexone. The key is
to encourage patients and to reassure them that these
symptoms should get better with time. Alcohol withdrawal can
be managed with support or benzodiazepines if indicated (see
TIP 19, Detoxification from Alcohol and Other Drugs; CSAT,
1995).
Ongoing Treatment With
Naltrexone
Maintenance Doses
The
currently recommended maintenance dose of naltrexone is 50
mg/day. However, maintenance doses of less than the standard 50
mg/day regimen may be considered in patients who do not tolerate
the standard maintenance dose but who are otherwise good
candidates for naltrexone. It is preferable to decrease the
maintenance dose to 25 mg/day to avoid noncompliance and relapse
due to common adverse effects rather than to rule out naltrexone
as a treatment option for these patients. Some patients may ask
to take naltrexone twice daily in order to experience subjective
relief from craving. In these cases, the same daily dose may be
divided in two and given at those times of the day when craving
is strongest.
Under certain circumstances, providers may increase the daily
naltrexone dose to greater than 50 mg. Patients who may be
considered for an increase include those who report persistent
feelings of craving, discomfort, and even brief relapses,
despite compliance with their treatment plan. In such cases,
dosages of 100 mg/day are sometimes used, with appropriate
medical monitoring. There is evidence that naltrexone is well
tolerated, safe, and effective at these higher doses (McCaul, 1996),
except with some very obese patients (Gonzalez and Brogden,
1988). For patients who miss occasional doses, higher
naltrexone doses may provide greater protection. Compliance
enhancement techniques are currently being evaluated, which may
eventually reduce the number of missed doses. As the number of
missed doses decreases, the patient may be able to return to
previous, lower dosages.
Before adjusting dosage, providers should first consider
intensification of other treatment interventions, particularly
psychosocial components. The reason that the medication is not
working should be explored. For example, adverse effects may
lead to skipped doses and would suggest the need for a lower
rather than higher naltrexone dose. Conversely, a patient's
request may sometimes be justification enough for a dose
increase, especially in those who are at high risk for relapse.
It is preferable to increase the dose in anticipation of, rather
than in response to, relapse. Naltrexone is not a drug of abuse,
and providers should view a patient's request for increased dose
as a sign of engagement and motivation in treatment, not as
drug-seeking behavior.
In some outpatient treatment settings (see
Oslin et al., 1997, and studies of patients addicted to
opiates), higher doses of naltrexone have been given
under observation either 2 days a week or 3 days a week. If this
is necessary and the patient tolerates a higher dose, then the
protocol typically is Monday 100 mg, Wednesday 100 mg, and
Friday 150 mg.
Duration of Treatment
The
goal for the patient taking naltrexone is to eventually
discontinue the medication without relapsing. It would be a
mistake to assume--or to mislead patients--that somehow the
medication, rather than the patient him- or herself, will do the
work of achieving and maintaining the goals of treatment. It
must be remembered that alcoholism is a chronic disease and,
like most chronic diseases, is likely to require continued
monitoring to maintain lifelong remission of the disease.
Although FDA guidelines indicate that naltrexone should be used
for up to 3 months to treat alcoholism, the Consensus Panel
recommends that treatment providers individualize the length of
naltrexone treatment according to each patient's needs.
Initially, the patient can be treated with naltrexone for 3 to 6
months, after which the patient and the therapist can reevaluate
the patient's progress.
At this time, the decision to extend treatment must be based on
clinical judgment. Although the results of studies on the
efficacy of other durations of naltrexone treatment for alcohol
dependence are forthcoming, naltrexone has been used for
extended periods ranging from 6 months to several years in the
treatment of opiate addiction, suggesting that longer term
treatment is safe. Safety data have been presented on the use of
naltrexone in alcohol-dependent patients up to 1 year with no
new safety concerns noted (Croop and Chick, 1996).
Pending definitive research results, the Consensus Panel concurs
that certain patients may be appropriate candidates for
long-term (e.g., up to 1 year) naltrexone treatment if they
demonstrate evidence of compliance with medication and
psychosocial treatment regimens. Factors to be weighed in the
clinical decision to extend treatment beyond 3 to 6 months
include the following:
-
Patient interest. Continued patient interest in taking
naltrexone is usually an indication that the patient is
engaged in treatment and perceives the medication as helping
maintain his or her sobriety. Patients who wish to continue
naltrexone treatment after an initial period of sustained
abstinence may be considered for long-term treatment.
-
Recent dose adjustments. Although the duration of
treatment should always be individualized, it is generally
recommended that naltrexone treatment can be discontinued
after 3 to 6 months of sustained abstinence. Thus, when a
clinical response has been achieved only recently,
naltrexone treatment can continue for at least another 3
months in order to provide optimal care.
-
Partial treatment response. Some patients have a partial
response to naltrexone treatment. Examples are a patient who
achieves a reduction in drinking but continues to have
episodes of clinically significant drinking, or one who
progresses toward treatment goals without achieving
sufficient stabilization. These patients may be appropriate
candidates for additional naltrexone treatment and dose
adjustments. In general, the success of treatment must be
measured across a spectrum of outcomes; failure to achieve
total abstinence should not be considered synonymous with
failure of treatment.
-
Prophylaxis in high-risk situations. Although established
data are currently lacking, some animal studies (e.g.,
Reid et al., 1996) and a recent open-label
clinical study (Kranzler
et al., 1997) suggest that after an established
course of daily treatment, naltrexone may be effective on an
intermittent or as-needed basis. In certain circumstances,
continued naltrexone treatment may be considered as
prophylaxis for patients who anticipate a high-risk
situation or who undergo major stressors or lifestyle
changes that increase the risk of relapse.
Other Clinical
Considerations During Treatment
Followup liver function
tests
After
the initial screening, followup LFTs should be completed after 1
month of naltrexone treatment. If the results are acceptable,
followup LFTs may then be conducted at 3 and 6 months after the
initiation of treatment, depending on the severity of liver
dysfunction at the start of treatment.
More frequent monitoring is indicated for cases in which dose
adjustments are being made, baseline LFTs are high, there is a
history of hepatic disease, disulfiram or other potential
hepatic-toxic medications are added to the treatment, or
symptomatology indicates the need for monitoring. Prescribing
physicians should also educate the patient regarding the signs
and symptoms of hepatic toxicity (white stools, dark urine,
yellowing of eyes). A clinically significant increase (three to
five times or more) over recent LFT results or an elevation in
bilirubin signals a need for discontinuation, as do other
clinical signs of hepatic toxicity. In such cases, the treatment
provider should discontinue naltrexone treatment, sort out the
causes for the increased LFT results, and retest the patient
before reinstating the medication.
The Consensus Panel suggests that some clinicians may want to
monitor LFTs as a clinical indicator of treatment response and
also as a form of encouragement for patients. LFTs can be used
to verify self-reports of drinking and to encourage patients
whose enzyme levels show improvement.
Pregnancy
During
treatment, female patients should be instructed to inform their
caregivers if they suspect that they may be pregnant or
experience a delay or change in their menstrual cycles. If a
patient becomes pregnant, naltrexone should generally be
discontinued.
Pain management
Naltrexone
is an opioid antagonist and will, therefore, block the effects
of usual doses of therapeutic opioids, including codeine,
hydrocodone bitartrate, oxycodone hydrochloride, morphine, and
meperidine hydrochloride (Demerol), among others. If the patient
has a pain condition that requires treatment, providers should
use nonnarcotic methods of analgesia as first line of treatment
if possible. Naltrexone will not reduce the effectiveness of
nonnarcotic analgesics (i.e., nonsteroidal anti-inflammatory
medicines, spinal blocks, general and local anesthesia). If
narcotic pain relief is indicated, patients must discontinue
naltrexone use for the period during which analgesics are
required. If a painful event is anticipated, such as scheduled
surgery or dental work, naltrexone should be discontinued 72
hours prior to the procedure. If a patient is taken off
naltrexone and put on an opioid analgesic, he or she should be
abstinent from the narcotic for 3 to 5 days before resuming
naltrexone treatment, depending on the duration of opioid use
and the half-life of the opioid. A more conservative approach is
to wait 7 days. Alternate methods are to administer the naloxone
challenge test or to titrate the naltrexone dose and observe
patient reactions. Again, these decisions should involve a
risk-benefit analysis and should incorporate the patient's need
for addiction treatment.
In emergencies such as cases of acute severe pain, higher doses
of opioid analgesics may be used with extreme caution to
override the blockade produced by naltrexone. The narcotic dose
needs to be carefully titrated to achieve adequate pain relief
without oversedation or respiratory suppression. Both the dose
and the patient's vital signs (including respiratory rate, level
of awareness, and level of analgesia) must be closely monitored.
The capability of respiratory assistance and support must be
available, should this be necessary.
Patients with chronic pain that does not respond to nonnarcotics
are not candidates for naltrexone treatment. Therefore, patients
with sickle cell disease, hemophilia, recurrent kidney stones,
or other high-risk conditions (e.g., advanced cancer or chronic
pancreatitis from alcoholism) requiring narcotic analgesia also
are not good candidates.
Finally, the Consensus Panel notes that issues of pain
management and emergency treatment--for which a patient is
likely to come under the care of someone other than the primary
care provider--underscore the importance of issuing safety
identification cards to patients on naltrexone (see
Figure 2-5). These cards provide information that the
patient is receiving naltrexone and instructions for treating
patients in the event of an emergency. These cards are available
for free to clinics from the manufacturer of naltrexone
(1-800-4PHARMA), or they can be prescribed from the pharmacy
with the first dose. If such a card is not on hand, provide the
patient with the physician's card, including the patient's name,
and state in large print that naltrexone is being taken; include
a 24-hour telephone number for the prescribing physician's
service.
Continued drinking
Although
abstinence is the goal of naltrexone therapy, some patients who
are compliant with treatment may continue to drink alcohol
periodically. This is not a sufficient reason to discontinue
naltrexone: Some patients respond to naltrexone treatment at
first by reducing rather than stopping their drinking. Total
abstinence should be a long-term goal, not a condition of
initial treatment. Most treatment programs are generally
tolerant of incremental steps toward that goal, while setting
good boundaries for patients who are relearning how to live
without alcohol.
When a patient drinks during treatment, the clinician should
evaluate whether the patient is taking his or her medication
regularly and participating in treatment actively, because these
factors are related to treatment improvement (Volpicelli et al., 1997).
Alcohol treatment programs have many skills and strategies for
improving compliance, all of which should be explored with the
patient. For example, the patient's routine for taking
medication can be reviewed and modified. The intensity of care
along with the expectations placed on the patient may also be
stepped up. This may include stepping up the frequency of
sessions or attendance at self-help groups or support group
meetings. As discussed earlier, dose adjustments may also be
indicated. Prescription refill frequency may be changed, and the
medication may be dispensed in blister packs to improve
compliance. Each physician working with a treatment program must
participate in the reevaluation of the goals of treatment and
those of the patient in order to decide how to proceed. Direct
communication between the treatment team and the physician is
another key to success.
Use of naltrexone in
conjunction with disulfiram
The
ways in which treatment programs use disulfiram with naltrexone
vary according to treatment goals and institutional policies.
Some examples of models of dual therapy are as follows:
-
Primary use of disulfiram, with naltrexone introduced to
abate persistent complaints of craving
-
Initial use of disulfiram to establish a period of
abstinence prior to initiating naltrexone therapy, then
discontinuing disulfiram
-
Use of disulfiram as prophylaxis in high-risk situations
in patients taking naltrexone
-
Short-term use of disulfiram in patients who have
continued to drink periodically in order to help them break
this cycle and achieve a sustained period of abstinence
The
safety and efficacy of concomitant use of naltrexone and
disulfiram are unknown, and the concomitant use of two
potentially hepatotoxic medications is not ordinarily
recommended unless the probable benefits outweigh the known
risks. Patients should always check with the prescribing
physician about any medications taken with naltrexone.
If naltrexone is used with disulfiram, then treatment providers
should perform LFTs shortly after the initiation of combined use
of disulfiram and naltrexone. Providers should retest patients
every 2 weeks for 1 to 2 months and then at regular intervals,
such as monthly, thereafter. Combination therapy with disulfiram
and naltrexone is not used for very long periods, and generally
the two drugs are not started simultaneously.
Ending Naltrexone Therapy
Successful Termination Of
Naltrexone
The
usual naltrexone dose of 50 mg/day can be discontinued without
tapering the dose because there is no withdrawal syndrome
associated with naltrexone therapy. The same appears to be true
for higher doses of naltrexone. Nonetheless, dose reductions may
be useful psychologically for some patients. For example,
patients might begin to take the medication every other day, and
then at times of greatest risk for drinking (e.g., weekends,
social gatherings),and then discontinue the medication
altogether. A similar strategy has been used successfully with
calcium carbimide(Annis and Peachy Peachey,
1992)and is currently being investigated for
naltrexone(Kranzler et al., 1997).The
treatment team should work with the patient in developing
Whenever possible, treatment providers also help the patient's
family prepare for treatment closure. It is important for both
the patient and the family to recognize the components of
treatment that have been successful in helping the patient to
maintain sobriety, including the patient's own efforts, newly
acquired skills, and the active support of his or her family.
Monitoring the Outcome Of
Treatment
In
evaluating the outcome of naltrexone therapy, providers should
expect to see evidence of positive improvement over time as
evaluated by the treatment program's indicators of progress. The
following lists some of the possible criteria that can be used
and selected to fit each program's needs and policies:
Compliance with treatment plan. Areas of patient compliance
include keeping appointments for medication monitoring,
prescription refills, counseling sessions, and group meetings,
as well as keeping agreements about payment for treatment.
Naltrexone is clinically effective compared with placebo when
the patient is highly compliant, that is, taking the medication
as prescribed, and completing psychosocial treatment as planned (Volpicelli et al., 1997).
Stable abstinence or significant reduction in the frequency and
amount of drinking. Studies suggest that long-term outcomes are
better for patients who maintain abstinence during treatment (O'Malley
et al., 1996a). Alcoholics Anonymous (1976) or other
self-help groups can help support this as an outcome.
Improvements should be confirmed by the following:
-
Patient self-reports. The patient's own self-reports can
be useful indicators of treatment success. The provider
should initiate a discussion with the patient about the
quantity and frequency of drinking, especially during
stressful periods (e.g., holidays, major life changes).
-
Collateral reports. Those in regular contact with the
patient, such as family members and employers, can provide
confirmatory reports of the patient's sobriety. The
treatment provider must obtain the patient's written consent
before communication with these individuals takes place.
Such collateral reports may be useful, but it is important
to bear in mind that although they can tell the provider
whether the patient has been drinking, they rarely provide
insight into the quantity and frequency of drinking and
thereby whether the patient has experienced an actual
relapse.
-
Biological markers. Although a new marker of recent
drinking--carbohydrate-deficient transferrin--is on the
horizon and may prove to be a more accurate marker than
serum aminotransferases, the test for this marker is not yet
widely available. For the present, it is best to rely on
standard LFT results as biological markers for alcohol
intake. In addition, providers can use periodic random
Breathalyzer™ tests to monitor alcohol intake and to
provide positive feedback to patients who are successful in
maintaining abstinence.
Markedly
diminished craving. Craving that has diminished greatly is an
optimum outcome of naltrexone treatment. To assess craving, the
patient's own subjective reports can be largely relied on,
although objective measures may also prove useful. More
important than the method of monitoring is consistency in how
the patient is asked about craving patterns and trends.
Assessment of craving is most useful within the context of
specific time frames. Patients should be asked about craving at
the present time as well as how they have been feeling over the
past week. It may be useful to ask them to rate their most
intense episode of craving and whether any episodes of craving
have caused particular problems for them. The pattern of craving
over time is a more telling indicator than an absolute number on
a scale. In this way, both the provider and the patient can see
that the patient's patterns of craving may be fluctuating
throughout the day and over longer periods, which can provide a
more accurate assessment of the appropriateness to continue,
adjust, or terminate naltrexone treatment. Self-report
instruments have been developed to assess craving. Examples
include the Alcohol Urge Questionnaire (Bohn et al., 1995),
which has the advantage of being short and easy to administer,
and the Obsessive Compulsive Drinking Scale (Anton et al., 1996).
These instruments are presented in Appendix
D. It is important to educate the patient about the
role of craving in relapse.
Improvement in quality of life. Ultimately, one of the goals of
treatment is improved quality of life. In this regard, it is
important to identify changes over time and to view the goal as
being an improvement, rather than a total elimination, of
problems. Areas to be assessed should include
-
Health:
-
Blood
pressure, previously elevated, returns toward normal
-
LFT
results show improvement
-
Stabilization
occurs for other related medical problems that the patient
was experiencing when he or she began treatment (such as
control of blood glucose, stabilization of asthma,
cardiomyopathy, encephalopathy, or ascites and edema)
-
Signs
of increased engagement in general health care, such as
seeing a physician for the first time in years and/or
increased compliance with prescribed medication regimens
other than naltrexone (e.g., asthma or blood pressure
medications)
-
Family:
-
Spending
more positive time with children and/or spouse
-
Greater
involvement/participation with family members
-
Improved
intimate relationships
-
Reduced
family conflict (see TIP 25, Commented out
ElementSubstance Abuse Treatment and Domestic
ViolenceCommented out Element [CSAT, 1997], for issues
concerning substance abuse and domestic violence)
-
Work/vocational status:
-
Engagement
in nondrinking leisure and recreational activities
-
Obtaining
employment
-
Improved
attendance at work
-
Fewer
job-related problems
-
Improved
job performance
-
Legal status:
-
No
new parole or probation violations
-
No
new driving-under-the-influence charges
-
Mental status:
-
Decreased
psychological symptoms
-
Decreased
irritability and anxiety
-
Improved
mood
-
Improved
sleep
-
Getting
appropriate treatment for anxiety disorders, depression,
or schizophrenia rather than self-medicating with alcohol
Abstinence
from other substances of abuse. It is important to focus not
just on alcohol use but also to address other substances of
abuse that pose the same level of concern and possible adverse
consequences. The abuse of other substances can be evaluated by
random urinalysis, collateral reports from family or employer
(with the patient's written consent), and self-reports from the
patient. In addition to illicit substances, abuse of
prescription and nonprescription medications is an important
issue and should be addressed. In this regard, the patient's
agreement or resistance to continuing treatment may indicate the
level of willingness to consider the abuse of other substances
as a problem.
Over
the past decade, basic neurobiological research has enhanced our
understanding of the biological and genetic causes of addiction.
These discoveries have helped establish addiction as a
biological brain disease that is chronic and relapsing in nature
(Leshner,
1997). By mapping the neural pathways of pleasure and
pain through the human central nervous system (which includes
the spinal cord and brain), investigators are beginning to learn
how abused psychoactive drugs, including alcohol, interact with
various cells and chemicals in the brain. As scientists increase
their knowledge, medications are being designed to reverse,
control, or minimize the negative effects of substance abuse (Charness, 1990; Kuhar, 1991; National Institute on
Alcohol Abuse and Alcoholism [NIAAA], 1994).
Fundamentals of the Nervous
System
The
human nervous system is an elaborately wired communication
system that networks the entire body, and the brain is the
central communications center of this system. The brain
processes sensory information from throughout the body, guides
muscle movement and locomotion, regulates a multitude of bodily
functions, forms thoughts and feelings, and controls all
behaviors. The fundamental functional unit of the nervous system
is a specialized cell called a neuron, which conveys information
both electrically and chemically. The function of the neuron is
to transmit information: It receives signals from other neurons,
integrates and interprets these signals and, in turn, transmits
signals on to other, adjacent neurons (Charness,
1990).
A typical neuron (see
Figure 3-1) consists of a main cell body (which
contains the nucleus and all of the cell's genetic information),
a large number of short-branched filaments called dendrites, and
one long fiber known as the axon. At the end of the axon are
additional filaments that form the connections with the
dendrites of other neurons. Within neurons, the signals are
carried in the form of electrical impulses. But when signals are
sent from one neuron to another, they must cross a gap from one
cell membrane to another. The gap at the point of connection
between the neurons is called a synapse. At the synapse, the
electrical signal within the neuron is converted to a chemical
signal. The chemical messengers that transmit the signal are
called neurotransmitters. Neurons communicate with other neurons
by releasing neurotransmitters, which travel across the synapse
and bind or adhere to specially formed receptors that are lodged
on the outer surface of the target neuron (Charness, 1990).
Approximately 50 to 100 different endogenous neurotransmitters,
with one or many binding sites or receptors, have been
identified in the human body. Figure
3-2 illustrates a typical synaptic connection and
depicts the chemical communication mechanism. Neurotransmitters
may have different effects depending on the subtype of receptor
activated. Some increase a receiving neuron's responsiveness to
an incoming signal--an excitatory effect--whereas others may
diminish the responsiveness--an inhibitory effect. The
responsiveness of individual neurons within the brain affects
how the brain functions as a whole (how it integrates,
interprets, and responds to information), which in turn affects
the function of the body and the behavior of the individual. The
accurate functioning of all neurotransmitter systems is
essential to ensure normal brain activities (NIAAA,
1994; Hiller-Sturmhöfel,
1995).
Neurological Reinforcement
Systems And Drug Dependence
Psychologists
have long recognized the importance of positive and negative
reinforcement for learning and sustaining particular behaviors (Koob and LeMoal, 1997).
Beginning in the late 1950s, scientists observed in animals that
electrically stimulating certain areas of the brain led to
changes in mental alertness and behavior. Rats and other
laboratory animals could be taught to self-stimulate pleasure
circuits in the brain until exhaustion. If cocaine, heroin,
amphetamines, or nicotine were administered, for example,
sensitivity to pleasurable responses was so enhanced that the
animals would choose electrical stimulation of the pleasure
centers in their brains over eating or other normally rewarding
activities. The above process in which a pleasure-inducing
action becomes repetitive is called positive reinforcement.
Conversely, abrupt discontinuation of alcohol, opiates, and
other psychoactive drugs following chronic use was found to
result in discomfort and craving. The motivation to use a
substance in order to avoid discomfort is called negative
reinforcement. Positive reinforcement is believed to be
controlled by various neurotransmitter systems, whereas negative
reinforcement is believed to be the result of adaptations
produced by chronic use within the same neurotransmitter
systems.
Experimental evidence from both animal and human studies
supports the theory that alcohol and other commonly abused drugs
imitate, facilitate, or block the neurotransmitters involved in
brain reinforcement systems (NIAAA, 1994). In
fact, researchers have posited a common neural basis for the
powerful rewarding effects of abused substances (for a review, see Restak,
1988). Natural reinforcers such as food, drink, and
sex also activate reinforcement pathways in the brain, and it
has been suggested that alcohol and other drugs act as chemical
surrogates of the natural reinforcers. A key danger in this
relationship, however, is that the pleasure produced by drugs of
abuse can be more powerfully rewarding than that produced by
natural reinforcers (NIAAA, 1996).
Unlike many other drugs of abuse (e.g., opiates, phencyclidine),
alcohol does not interact with a specific receptor in the brain
but appears to stimulate the release of many neurotransmitters (Koob
et al., 1994). The development and persistence of
alcohol dependence is a complicated process that is not yet
completely understood. A number of lines of research are
currently proceeding simultaneously to better understand the
interaction between neurotransmitters and their receptors in
encouraging drinking and the development of alcohol dependence (Froehlich, 1995).
Investigations have recently confirmed that the key
neurotransmitter systems that apparently interact with each
other to mediate the reinforcing effects of alcohol include
endogenous opioids, dopamine, serotonin, gamma-aminobutyric acid
(also known as GABA), and the excitatory amino acid glutamate.
Alcohol and
Neurotransmitters
Endogenous
opioids, a class of neuropeptides that includes endorphins and
enkephalins, produce euphoric, pleasurable effects such as
"runner's high"; these neuropeptides also reduce
sensitivity to pain. Heroin and morphine (which are called
opiates; see Figure
3-3 for a comparison of opiates versus opioids) mimic
the effects of endogenous opioids by stimulating opioid
receptors. Alcohol also stimulates the release of endogenous
opioids, which in turn activate the central
dopamine reward system (Koob
et al., 1994; Froehlich,
1996, 1997).
Dopamine produces immediate feelings of pleasure and elation
that reinforce such natural activities as sex and eating in both
humans and animals and motivates the repetition of these
activities. Dopamine is believed to play an important role in
reinforcement and motivation for repetitive actions (Di Chiara, 1997; Wise, 1982).
Alcohol appears to increase dopamine release in a dose-dependent
manner; that is, more dopamine is released when higher doses of
alcohol are given (Nash, 1997; Ulm et al., 1995).
It is believed that alcohol stimulates dopamine release via both
indirect mechanisms (gustatory stimuli) and direct actions on
the brain and that alcohol-induced stimulation of dopaminergic
pathways in the brain may be at least partially controlled by
the endogenous opioid system (Di Chiara, 1997; Froehlich and Wand, 1996).
Serotonin is associated with the reinforcing effects of many
abused drugs through its mood-regulating and anxiety-reducing
effects. Low levels of serotonin are associated with depression
and anxiety.
Both animal and human studies have shown that alcohol
administration increases levels of serotonin (LeMarquand
et al., 1994; McBride
et al., 1993). Selective serotonin reuptake
inhibitors (SSRIs), a class of medications that includes
fluoxetine (Prozac), increase serotonin concentrations in the
brain. SSRIs have shown some efficacy in decreasing alcohol
intake in both animals and humans (Ulm et al., 1995)
and have shown some promise in treating alcohol-dependent adults
(Naranjo et al., 1984,
1987, 1989, 1990). However,
several small clinical trials have shown only modest effect of
serotonergic agents in reducing alcohol consumption (Anton,
1995).
GABA is the primary inhibitory neurotransmitter in the central
nervous system. Because alcohol intoxication is accompanied by
the impaired coordination and sedation indicative of neuronal
inhibition, researchers have investigated alcohol's effects on
GABA and its receptors. The results of this research have shown
that alcohol significantly alters GABA-mediated
neurotransmission (for a review, see Mihic and Harris,
1997). GABAA (a subtype of GABA) receptors are also
believed to mediate development of tolerance and dependence on
alcohol. Alcohol is believed to exert its acute behavioral
effects by a selective enhancement of GABAA receptor activity (Little, 1991).
In support of this belief, GABAA receptor antagonists block the
ability of alcohol to cause ataxia (inability to coordinate
muscle activity during voluntary movement) and anesthesia (Frye and Breese, 1982;
Liljequest and Engel, 1982).
Alcohol also potentiates the effects of GABA in the cerebral
cortex and cerebellum (Suzdak
et al., 1986; Allan
and Harris, 1987).
Glutamate, an excitatory neurotransmitter, is associated with
many learning, memory, and developmental processes. Alcohol
normally inhibits the effects of glutamate. However, during
abstinence following chronic alcohol use, excitation of the
glutamatergic system is believed to have a role in alcohol
withdrawal-induced seizures (Gonzales
and Jaworski, 1997).
In addition to affecting neurotransmitters, it appears that
chronic use of alcohol may alter the structure and functioning
of neurotransmitter receptors that have roles in intoxication,
reinforcement, and dependence. Alcohol also may alter signal
transduction, which is the process of converting messages from
the signaling neuron into changes in the target neuron. Alcohol
dependence is also known to have a genetic component involved in
vulnerability to drug abuse and dependence. Studies have found
that identical twins, who share a common genetic heritage, are
more likely to share addictions than fraternal twins, who share
only half their genes (Pickens
et al., 1991). Similarly, men with alcoholic fathers
are three to five times more likely than men without any
familial history of alcoholism to experience early onset of
alcoholism or other drug dependence (Goodwin et al., 1973;
Cloninger, 1987, 1988). Laboratory
animals can be bred to show a greater preference for alcohol,
compared with other strains of the same species (Froehlich, 1995; NIAAA, 1994, 1996). A number
of recent lines of research have been focused on examining
differences in the genes, as well as endogenous levels of
various neurotransmitters, in rodents and humans differing in
genetic predisposition toward alcohol dependence.
Preclinical Research
Linking Alcohol and Opioids
For
more than 100 years, careful observers have noted that alcohol
and opiates produce similar pharmacological effects of euphoria
and sedation, even though these drugs have very different
chemical structures. A certain degree of cross-tolerance between
these drugs has been demonstrated in animals: Morphine will
relieve alcohol-withdrawal symptoms in mice, whereas alcohol
suppresses withdrawal symptoms in morphine-addicted rats (Volpicelli et al., 1991).
A Sears catalog from the early 1900s reflects the same
phenomenon in humans by advertising an opium-based treatment for
alcoholism and a tincture of alcohol for relieving the opiate
(laudanum) addiction that was common among women of that era. In
the 1970s, addiction specialists noted that opiate addicts would
substitute alcohol for heroin when the latter was unavailable.
In fact, opiates have often been described as a substitute drug
for alcohol, and an increase in opiate availability has been
reported to be accompanied by a decrease in alcohol drinking (for
a review, see Siegel, 1986). Opiate addicts are known
to increase alcohol consumption during withdrawal and decrease
alcohol consumption during methadone treatment or when heroin or
morphine is readily available and consistently used (Ulm
et al., 1995; Volpicelli
et al., 1991).
These observations and other research findings set the stage for
more intensive preclinical investigations over the past 15 years
into the links between alcohol consumption and both endogenous
opioids and exogenous opiates. These studies found that
-
Alcohol administration releases endogenous opioid
peptides
-
Important genetic differences exist in opioid response to
alcohol consumption
-
Opiate administration alters alcohol consumption
-
Opioid receptor antagonists change alcohol consumption
patterns
Alcohol's Effects on
Release of Endogenous Opioids and Opioid Receptor Activity
For
some time, scientists have suspected that alcohol stimulates
release of endogenous opioids and affects opioid receptor
activity. Alcohol consumption has been shown to stimulate the
release of endorphins in both rodents and humans (Gianoulakis and Barcombe,
1987; Gianoulakis and
Angelogianni, 1989; Gianoulakis et al., 1987,
1996; Thiagarajan et al., 1989)
as well as in cell cultures of rat hypothalamus and pituitary (Gianoulakis and Barcombe,
1987; Gianoulakis et
al., 1990; Keith et al.,
1986). More recently, animal studies have also
demonstrated that alcohol exposure also increases levels of
another class of opioid peptides, the metenkephalins. Moreover,
studies using rodents bred specifically for preference or
nonpreference for alcohol and in humans with a positive or
negative family history of alcoholism indicate that a genetic
predisposition toward alcohol consumption is accompanied by
alterations in the responsiveness of the endogenous opioid
system (deWaele
et al., 1992). Acute alcohol administration produces
greater increases in release of endogenous opioids and larger
increases in opioid peptide gene expression in
alcohol-preferring rodents than in nonpreferring rodents (Froehlich, 1995; Froehlich and Wand, 1996).
Acute alcohol administration has also been shown to increase
endorphin and enkephalin gene expression and to increase opioid
receptors in neuronal cell cultures (Charness
et al., 1986, 1993;
Jenab and
Inturrisi, 1994; Li et al., 1996).
Recently, Gianoulakis and colleagues found that individuals with
a positive family history of alcoholism have lower baseline
levels of beta-endorphins than individuals with no family
history of alcoholism (Gianoulakis et al., 1996).
Effects of Exogenous Opiate
Administration and Withdrawal on Alcohol Consumption
A
related line of research has explored the impact of exogenous
opiates on alcohol consumption in animal models. Early studies
found that rats injected with a single, high dose of morphine
(30 mg/kg) decreased their alcohol consumption (Sinclair, 1974)
and that this effect of morphine was dose dependent (Ho et al., 1976).
These studies also reported that morphine administration did not
alter water consumption, suggesting a selective effect of
morphine on alcohol-drinking behavior (Sinclair,
1974). Self-administration of alcohol also increased
if moderate to large doses of opioids were abruptly terminated
and withdrawal symptoms precipitated (Volpicelli
et al., 1991; O'Brien
et al., 1996).
In contrast to these earlier findings, Reid and colleagues found
that small doses of morphine (<2.5 mg/kg) transiently
increased the preference for alcohol in previously
fluid-deprived rats when given limited (2-hour) access to
alcohol or water immediately after injection (Reid et al., 1991).
These results suggested that small doses of opiates or other
pleasure-inducing drugs may have a priming effect in which small
amounts of the rewarding substance increase the craving to
consume more of the same substance. In contrast, if opioid
receptors are already saturated by high levels of externally
administered opioid agonists such as morphine or heroin, then
drinking decreases.
Similarly, an addictive cycle (Figure
3-4) may be established in animals or humans as a
result of consuming a small dose of alcohol, which like a small
dose of morphine leads to modest increases in opioid receptor
activity. Once opioid receptor activity has been primed, more
alcohol is needed to ensure continued opioid receptor activity (Volpicelli et al., 1994).
Therefore, a cycle may ensue during which the desire to increase
or recapture feelings of pleasure or euphoria (particularly if
withdrawal results in lower levels of the desired feeling) is
translated into cravings for particular substances. The loss of
control that follows the initial consumption of a reinforcing
agent may provide the root mechanism for some, if not all,
addictive behaviors.
Effects of Opioid
Antagonists on Alcohol Consumption
Nonselective
opioid antagonists like naloxone and naltrexone block opioid
receptors and reverse the effects of endogenous opioid peptides
as well as exogenous opiates (Froehlich,
1995; Swift,
1995). Studies conducted in both rodents and monkeys
have demonstrated that naloxone and the longer acting naltrexone
attenuate voluntary self-administration of alcohol and
stress-induced increases in alcohol consumption, suggesting that
these agents may prevent the reinforcing effects of alcohol
consumption (Froehlich and Li, 1993;
O'Brien et al., 1996).
Pretreatment with opioid antagonists reverses most of the
effects of endogenous opioids or exogenous opiates on alcohol
preference. Two double-blind, placebo-controlled clinical trials
on the effects of naltrexone on alcohol drinking in outpatient
alcohol-dependent patients demonstrated that naltrexone can
decrease the mean number of drinking days per week, the
frequency of relapse, the alcohol-induced subjective
"high," and the desire to drink (O'Malley et al., 1992;
Volpicelli et al., 1992).
This
chapter describes the two clinical trials that initially
established the use of naltrexone as an effective adjunct to
psychosocial therapy in the treatment of alcohol dependence. In
addition, the chapter summarizes several newer trials of
naltrexone in different clinical populations, briefly reviews
other recent advances in pharmacotherapies for alcohol
dependence, highlights some of the clinical variables associated
with successful demonstrations of naltrexone's efficacy, and
suggests directions for future research. A summary of the most
relevant clinical findings with respect to naltrexone treatment
concludes the chapter.
Initial Efficacy Studies
The
efficacy of naltrexone treatment for alcohol dependence was
initially demonstrated by two back-to-back studies conducted
first at the Philadelphia Veterans Affairs (VA) Medical Center (Volpicelli
et al., 1992) and subsequently at Yale University
School of Medicine (O'Malley et al.,
1992). Both research projects were 12-week,
double-blind, placebo-controlled clinical trials that
administered either 50 mg/day of naltrexone hydrochloride or
identical-appearing placebo tablets with standardized
psychosocial therapy or rehabilitation counseling in small
outpatient samples. In the VA study, patients also participated
in day hospital treatment for 1 month followed by twice weekly
group therapy. The subjects in the Yale study received either
supportive therapy or cognitive behavioral coping skills
treatment once a week. The subjects were recently detoxified or
abstinent for 1 week and met diagnostic criteria for alcohol
dependence according to the Diagnostic and Statistical Manual of
Mental Disorders (3rd edition, revised
[DSM-III-R]; American Psychiatric Association, 1987).
The study populations in both trials had no significant
psychiatric illness or drug abuse problem other than alcohol.
The separate findings from both of these initial clinical trials
were encouraging because they demonstrated the benefits of
naltrexone as an adjunct to psychosocial therapy for the
treatment of alcohol dependence (O'Malley
et al., 1995). In fact, the findings were
instrumental in the approval given by the Food and Drug
Administration (FDA) in December 1994 to use naltrexone for this
purpose--the first new medication approved by the FDA for
treatment of alcohol dependence in nearly 50 years.
Three-Month Treatment
Outcomes
The
subjects who took naltrexone in the VA Medical Center study (Volpicelli et al., 1992)
had significantly more favorable outcomes than those randomized
to placebo in terms of decreasing the mean number of drinking
days, relapsing to clinically significant drinking, and
experiencing less craving for alcohol (see
Figure 4-1). Many of the subjects in both groups were
nonabstinent during the study (57 percent of the placebo cohort
and 46 percent of the naltrexone group). However,
naltrexone-treated subjects drank on an average of 1.6 percent
of study days compared with 8.3 percent of study days for the
placebo group. Only 23 percent of the naltrexone-treated
subjects met criteria for relapse to heavy drinking (five or
more drinks on an occasion, drinking on 5 or more days in a
week, or coming to a study appointment with a blood alcohol
concentration level above 100 mg/dl), whereas 54 percent of the
placebo-treated subjects relapsed.
The most impressive effect of naltrexone, however, was seen in
patients who did imbibe: Only 8 of 16 naltrexone-treated
subjects (50 percent) went on to a full-scale relapse after
sampling alcohol compared with 19 of 20 placebo-treated subjects
(95 percent). Mean alcohol craving scores, which declined
gradually over the course of the study in both groups, were
significantly lower at termination for the naltrexone group
compared with the placebo group in a covariate analysis taking
baseline craving into account. Craving in this study was
assessed by simply asking the subjects to rate their craving
from 0 to 9, where 0 was equivalent to no craving and 9 was
craving so severe that the subject was unable to resist a drink.
The results of the Yale study confirmed and extended those from
the first trial by Volpicelli and colleagues in finding
naltrexone superior to placebo on measures of abstention,
relapse, numbers of drinking days, amounts of alcohol consumed,
and severity of alcohol-related and employment problems (O'Malley et al., 1992).
Subjects who took naltrexone reported drinking on half as many
study days (4.3 percent) as placebo-treated subjects (9.9
percent). Moreover, the naltrexone-treated subjects, who
averaged 13.7 drinks during the trial, consumed only one-third
as many standard drinks as the placebo-treated controls, who
averaged 38 drinks. This difference was even greater between the
naltrexone-treated subjects who completed the study--who
averaged 12 drinks during the 12-week study--and those
placebo-using subjects who remained in the study but averaged 44
drinks over the 3-month period.
To further explore the links between the two independent
clinical trials that had slightly different subject populations
and rehabilitation approaches, a combined analysis of the data
from both studies was performed (O'Malley et al., 1995).
The results for a total of 186 subjects in the combined samples
(93 naltrexone- and 93 placebo-treated) validated the original
findings. The naltrexone-treated group had higher rates of
abstinence and significantly fewer relapses to heavy drinking
than did the placebo cohort, particularly among the subset of
subjects who did resort to alcohol consumption during the
3-month trials. Placebo-treated subjects were nearly twice as
likely (1.87 times) as those receiving naltrexone to
"slip" and, if they began to drink, they were also
twice as likely (1.92 times) as those not on active medication
to have an episode of heavy drinking. The naltrexone-treated
group also drank on fewer days throughout the studies than did
subjects who received placebo.
Six-Month Followup Results
O'Malley
and colleagues followed up 80 of the original 97 patients from
the Yale trial 6 months after discontinuation of treatment to
determine whether naltrexone in combination with either
supportive or coping skills therapy improved long-term outcomes (O'Malley
et al., 1996a). At followup, subjects in the
naltrexone-treated group had lower overall relapse rates and
were less likely to meet diagnostic criteria for alcohol abuse
or dependence, as measured by the alcohol section of the
Structured Clinical Interview for DSM-III-R (SCID), than were
the subjects who had received placebo. However, the positive
effect of naltrexone on abstinence rates only persisted for the
first month following termination of medication, and its impact
on relapse prevention declined over time. Moreover, by the end
of the sixth month, the subjects who had received placebo/coping
skills therapy had improved rates of drinking and relapse that
were similar to those of both naltrexone-treated groups. The
investigators speculated that the effects of coping
skills/relapse prevention training, even without medication,
take time to emerge but contribute to positive long-term
outcomes by providing specific tools and reinforcing a reliance
on personal resources after treatment cessation. They also noted
that abstinence during treatment was a strong predictor of
sustained improvement.
Predictors of Treatment
Response
Further
explorations of the data from the two original clinical trials (O'Malley et al., 1992;
Volpicelli et al., 1992)
have attempted to specify the characteristics of subjects most
responsive to naltrexone and the baseline variables that predict
continued alcohol consumption despite psychosocial treatments.
One purpose of such analyses has been to assist in the matching
of patients to the most appropriate treatments. These studies (Volpicelli
et al., 1995a; Jaffe
et al., 1996) suggest that patients with high levels
of alcohol craving or poor cognitive abilities tend to benefit
greatly from naltrexone therapy.
Recent Studies in Subjects
With Alcohol Dependence
Since
the results of the original trials of naltrexone were published
in 1992, several new studies have been completed and preliminary
results published or presented. Two of these investigations
highlight the importance of medication compliance to the
efficacy of naltrexone (Volpicelli et al., 1997;
Croop and Chick, 1996).
Volpicelli and colleagues conducted a 12-week study of 97
alcohol-dependent and recently detoxified patients at the
University of Pennsylvania/VA Treatment Research Center who were
randomized to placebo or naltrexone along with individual
therapy. Therapy focused on relapse prevention and occurred
twice a week for the first month, tapering to weekly sessions in
the second and third months (Volpicelli
et al., 1997). Although most of the procedures were
the same as those in the original VA Medical Center study of
male veterans (Volpicelli et al., 1992),
the patient population in this study was more heterogeneous,
with a broader mix of ethnicities, more women (approximately 25
percent), and more married participants. The psychosocial
treatment also was less intensive. Unlike the findings from the
original clinical trials, however, naltrexone was not
impressively superior to placebo in preventing relapse to heavy
drinking. Although only one-third of the total
naltrexone-treated group (35.4 percent) relapsed during the
study compared with more than half of the total placebo sample
(53 percent), these differences were not statistically
different.
The results of the 1997 study did more clearly favor naltrexone
over placebo among subjects who cooperated fully with the study
protocol, missing no more than two research sessions (Volpicelli
et al., 1997). Only one-fourth (25.7 percent) of the
35 naltrexone-treated subjects who completed the study
experienced a relapse compared with more than half (52.8
percent) of their counterpart treatment completers in the
placebo group. Naltrexone-treated patients who completed
treatment also reported less than half the number of drinking
days (5.4 percent) than did those who received placebo (12.7
percent) and were more likely to remain continuously abstinent
(64 percent vs. 35 percent). The investigators concluded that
the benefits of naltrexone in reducing relapse to heavy drinking
rely heavily on subjects' attendance and medication compliance.
Consistent with this conclusion, the preliminary results of a
double-blind placebo-controlled study of naltrexone conducted in
the United Kingdom also found that naltrexone was superior to
placebo only in the subset of patients who completed the 12-week
trial and took 80 percent of their study medication (Croop and Chick, 1996).
Thus, if the beneficial effects of this medication are to be
fully realized, outpatient programs will need to incorporate
naltrexone into a structured psychosocial treatment approach
that facilitates both types of compliance.
Anton (1997) recently
reported findings that more consistently favored naltrexone over
placebo. The preliminary results of this study of 131
mild-to-moderately severe outpatient alcoholics who were
relatively treatment-naïve indicated that naltrexone when
combined with cognitive behavioral therapy (CBT) increased the
nonrelapse rate from 40 percent in the placebo-treated group to
62 percent. In addition the percentage of days drinking and
drinks per drinking day were also significantly decreased by
naltrexone. Interestingly, the time between the first relapse
drinking day (defined as five or more drinks per day for men and
four or more drinks per day for women) and the second relapse
drinking day was almost double for those treated with naltrexone
and CBT compared with those receiving CBT alone. Naltrexone also
allowed subjects to experience greater control and resistance
over their thoughts about drinking and their urge to drink. Side
effects of nausea, abdominal discomfort, daytime sedation, and
nasal congestion were all experienced more frequently by the
naltrexone-treated patients compared with placebo-treated
patients.
Naltrexone was well tolerated by most patients: No one
terminated due to adverse effects, and liver function normalized
in a similar fashion in both the naltrexone- and placebo-treated
groups. The results of this study, in which the patients had
high treatment completion (83 percent) and medication compliance
(70 percent), support the initial findings of the two 1992
studies (O'Malley et al., 1992;
Volpicelli et al., 1992).
It indicates that naltrexone can augment a highly useful
psychosocial intervention in the outpatient treatment of
alcoholism.
The average age of subjects participating in most studies of
naltrexone is in the early forties. However, the population of
older adults in the United States is increasing rapidly, and
although little is known about the use of naltrexone with this
population, many older alcohol-dependent individuals may be
potential candidates for this medication. To address the
efficacy of naltrexone in older alcoholics, Oslin and colleagues
(Oslin et al., 1997)
conducted a 12-week double-blind placebo-controlled study of
male veterans, 50 to 70 years of age. Nursing staff administered
the naltrexone to ensure compliance, giving subjects 100 mg each
on Monday and Wednesday and 150 mg on Friday, using procedures
similar to those used for opiate addicts taking naltrexone.
Naltrexone was well tolerated by subjects, and they completed
nearly 10 of the 12 weeks on average. Because of the small
sample size, the differences between the groups could not be
considered statistically significant, though there were
observable trends. Specifically, 14.3 percent of those in the
naltrexone-treated group relapsed, compared with 34.8 percent of
those in the placebo-treated group (p = .117). However, among
those who sampled alcohol, only three of the six subjects in the
naltrexone-treated group subsequently relapsed, compared with
all eight subjects who drank in the placebo group. Although the
sample does not represent the oldest of the old, the study
suggests that naltrexone is a viable treatment option for older
adults.
Naltrexone Treatment For
Other Patient Populations
Several
studies have recently been completed, and more have been funded
to investigate the efficacy of this approach with a variety of
other patient populations, using different dosing levels and
schedules, therapy combinations, treatment intensities, and time
in care.
Cocaine and Alcohol Abuse
Concurrent
cocaine abuse by alcohol-dependent persons is a more common
problem than any other drug-alcohol combination, according to
recent Epidemiologic Catchment Area (ECA) data (Regier
et al., 1990). Drug-abusing alcoholic patients also
have poorer treatment prognoses than individuals who only drink
to excess. In an attempt to ascertain effective treatments for
this comorbidity, Carroll and colleagues randomly assigned 18
outpatients meeting DSM-III-R criteria for cocaine and alcohol
dependence but no other psychological disorder to either
disulfiram (250 mg/day) or naltrexone (50 mg/day) together with
weekly psychotherapy sessions over 12 weeks (Carroll
et al., 1993). Although the investigators
hypothesized that naltrexone would be associated with reductions
in alcohol use comparable to those of disulfiram and also have a
positive impact on cocaine use, disulfiram was found to be
significantly more effective than naltrexone in reducing the
frequency and quantity of alcohol use during treatment. Parallel
but lesser reductions in cocaine use were also found among the
subjects receiving disulfiram compared with those treated with
naltrexone. Although the sample size was small and attrition was
high in both groups (only four of nine subjects in the
disulfiram group and two of nine in the naltrexone group
completed all 12 weeks of treatment), the findings from this
pilot study are disappointing with respect to naltrexone's lack
of apparent efficacy as an adjunctive pharmacotherapy for
patients with comorbid alcohol and cocaine problems.
A larger study of 109 alcoholics of whom approximately
two-thirds had concomitant cocaine or opioid dependence found
that over the course of a 6-month medication period, naltrexone
was not significantly better than placebo in reducing alcohol
consumption and relapse drinking (McCaul, 1996).
However, early in the medication period (first and second
months), individuals treated with naltrexone 100 mg did
significantly better than the individuals treated with either
naltrexone 50 mg or placebo. Furthermore, there was evidence
that patients who had high blood levels of naltrexone's active
major metabolite did significantly better than patients with low
blood levels. A recent open-label study of naltrexone (150
mg/day) in alcohol- and cocaine-dependent adults did show
dramatic reductions in both alcohol and cocaine use (Oslin et al., 1997).
Thus, higher doses of naltrexone may be beneficial in this
select population. Additional trials at this higher dose are
currently being conducted.
Heavy Drinkers
A
1994 study randomized 14 heavy drinkers who met DSM-III-R
criteria for alcohol abuse or mild dependence (having no more
than three of the nine dependence criteria) to 6 weeks of brief
counseling (a 30-minute session in week 1, followed by 10-minute
"booster" sessions in weeks 2, 3, 4, and 6) and either
25 mg/day or 50 mg/day of naltrexone (Bohn et al., 1994).
Assessments were conducted during treatment, at termination, and
after a 1-month followup period. Total alcohol consumption
decreased in both dosage groups during the treatment period (63
percent from baseline) and over the entire course of monitoring
(48 percent). The intensity of drinking, frequency of heavy
drinking (a minimum of six drinks a day), craving for alcohol,
and indicator values of liver function tests also declined for
both groups during treatment; and subjects maintained these
improvements for the 1-month posttreatment period.
Researchers also have investigated the potential utility of
naltrexone on a targeted or "as needed" basis in an
open-label study of 21 individuals who had a diagnosis of
alcohol abuse or mild alcohol dependence and who drank more than
14 drinks per week for women and more than 20 drinks per week
for men (Kranzler et al., 1997).
Subjects were provided with four sessions of skills training and
five naltrexone tablets each week. They were instructed to take
at least two per week and to use the others as needed. During
the treatment period, significant improvements were observed on
a range of drinking-related outcomes. These measures included
frequency of drinking, amount consumed per drinking day, number
of drinking days, gamma-glutamyl transpeptidase (GGTP) levels,
alcohol problem severity, and craving. Over the course of the
3-month posttreatment followup, significant improvements were
still apparent for several measures, including frequency of
drinking, GGTP levels, drinks per drinking day, and the number
of heavy drinking days.
Although the sample size in these two studies was small and
there was no placebo control group, the results suggest that it
is feasible to use naltrexone in heavy drinkers and those with
milder alcohol-related problems who may present in primary care
settings. Placebo-controlled double-blind studies are currently
under way to follow up on these promising findings. Preliminary
analyses of a study in which open-label naltrexone was provided
in conjunction with a primary care model of counseling to
alcohol-dependent subjects also indicated that patients were
generally satisfied with this model of care and improved
significantly on a range of clinical outcomes (O'Connor et al., 1997).
Alcohol-Dependent Patients
With Comorbid Psychiatric Diagnoses
Given
that alcoholism is often associated with other psychiatric
disorders, investigators are beginning to describe the use of
naltrexone to augment the treatment response of the subset of
alcohol-dependent patients with comorbid psychiatric diagnoses.
Researchers reported that 82 percent of a sample of 72 dually
diagnosed patients had at least a 75 percent reduction in
drinking when treated clinically with 50 mg of naltrexone (Maxwell and Shinderman, 1997
[see
Case Study 1 in Appendix C]). A recent small
open-label study examined the effect of naltrexone on alcohol
use and depressive symptoms among 14 depressed alcoholics who
were continuing to drink despite selective serotonin reuptake
inhibitor (SSRI) therapy for depression (Salloum et al., 1998).
Encouragingly, the introduction of naltrexone to their
therapeutic regime was associated with significant reductions in
craving and drinking and mild improvement in depressive
symptoms. The combination of naltrexone and antidepressant
therapy also appears to be safe based on the results of the
large-scale multisite trial in which nearly one-third of the
patients were receiving concurrent antidepressant therapy
(almost all were taking SSRIs) (Croop et al., 1995,
1997). Larger
controlled studies are needed to conclusively evaluate the
potential effectiveness of naltrexone in dually diagnosed
patients.
Differential Subjective
Effects of Naltrexone
Clinical Studies
Additional
analyses of data obtained from the initial clinical trials of
naltrexone examined the subjective effects experienced while
drinking alcohol among subjects who did not remain abstinent
throughout the studies (Volpicelli et al., 1995b).
Of the 70 subjects in the original VA study, 36 met this
criterion (Volpicelli et al., 1992).
A larger proportion of these naltrexone-treated subjects (7 of
12) than placebo-treated subjects (2 of 17) reported that the
"high" produced by drinking alcohol was significantly
less than usual. The naltrexone-treated patients also drank less
alcohol than the placebo-treated subjects during the first
drinking episode--with only 17 percent of the naltrexone group
meeting relapse criteria during the initial slip compared with
65 percent of the placebo group. There was no difference between
groups in reported intoxication, loss of physical coordination,
levels of alcohol craving, memory disturbance, or loss of
temper. Volpicelli and colleagues speculated that these results
reflect the blockade effects of naltrexone on opioid receptor
activity with consequent loss of reinforcing pleasurable
stimulation, although an alternative explanation might be the
lower levels of alcohol consumed by the naltrexone-treated
subjects during their slips (Volpicelli et al., 1995b).
A similar reexamination of data from the original Yale study (O'Malley et al., 1992)
revealed differences between subjects in the naltrexone- and
placebo-treated groups with respect to their retrospective
recollections of subjective reactions to alcohol effects and
reasons for terminating an initial drinking episode (O'Malley
et al., 1996b). Although the mean number of drinks
consumed during the initial drinking episode did not differ
greatly, the proportion of subjects who met relapse criteria was
significantly lower for naltrexone-treated subjects (50 percent)
than for placebo-treated subjects (81 percent). The 16 patients
on naltrexone who did sample alcohol reported lower levels of
intoxication and lower levels of craving before, during, and
after their drinking episode than did their placebo-treated
counterparts. Furthermore, the two groups offered different
reasons for stopping drinking: The naltrexone-treated subjects
were more likely to report reduced incentives for drinking
(e.g., lower craving), whereas the placebo-treated subjects
emphasized various adverse consequences of drinking as reasons
for their stopping. The groups did not differ significantly in
their ratings of the pleasure associated with the experience.
The investigators concluded that the findings are consistent
with naltrexone's hypothesized effects on modifying alcohol
craving and the urge to drink among alcohol-dependent persons.
Laboratory Studies
Several
other laboratory studies have investigated naltrexone's effects
on subjective responses to drinking. Swift and colleagues used a
double-blind, cross-over design to determine whether
pretreatment with 50 mg of naltrexone affected a subsequent
intoxicating dose of alcohol given to 19 nonalcoholic subjects (Swift et al., 1994).
The results indicate that subjects reported feeling more sedated
and less stimulated during the experiment on the day that they
received naltrexone compared with the day that they received
placebo naltrexone. Naltrexone pretreatment did not alter
psychomotor performance or ethanol pharmacokinetics. Subjects
pretreated with naltrexone also had more episodes of nausea and
vomiting after the intoxicating dose of alcohol was
administered, suggesting that these aversive effects may also
decrease the desire to drink again. Given that nausea was not
assessed prior to alcohol ingestion, however, the results do not
clearly demonstrate whether the nausea was an adverse effect of
naltrexone alone or the result of an interaction between
naltrexone and alcohol. In fact, some dysphoria has been
reported by detoxified opiate addicts treated with naltrexone (Gonzalez
and Brogden, 1988). In direct contrast to the
findings by Swift and colleagues, a subsequent study found that
pretreatment with naltrexone did not significantly alter
subjective responses to alcohol among light social drinkers (Doty and deWit,
1995).
A more recent study of the effects of naltrexone on drinking
behavior found that naltrexone increased the time to the first
sip for the first and the second drink in social drinkers who
were observed in a bar setting over the course of 3 hours (Davidson et al., 1996).
In addition, blood alcohol levels were lower on the day that
subjects received naltrexone compared with the day that they
received placebo naltrexone, confirming observed differences in
drinking behavior.
King and colleagues noted that the euphoric effects reported by
clinical samples of alcoholics after drinking may not be the
same as those experienced by ordinary social drinkers (King
et al., 1997). Pursuing previously observed
differences in physiological responses to alcohol between
subjects who are genetically at high or low risk for the
development of alcoholism (Gianoulakis et al., 1990),
these researchers examined the effect of naltrexone in these two
groups on self-reported stimulation and sedation from alcohol as
well as general mood states during rising and falling phases of
intoxication as measured by breath alcohol levels (BALs). This
comparison of 15 high-risk males with alcoholic fathers and 14
low-risk subjects--with no alcoholic relatives in two
generations--confirmed the hypothesis that pretreatment with
naltrexone would decrease the subjective stimulation (euphoria)
experienced during the rising BAL phase immediately after
alcohol consumption in the high-risk social drinkers compared
with low-risk counterparts. The finding supports other research
reports in humans and animals that opioid receptor antagonists
decrease the reinforcing effect of drinking, especially among
those who are at genetic risk for developing alcohol dependence.
High-risk subjects in this study were also more likely than
low-risk participants to correctly distinguish the naltrexone-
from the placebo-influenced drinking sessions, reporting that
alcohol effects achieved after receiving the placebo were more
like everyday drinking. No significant naltrexone-related
sedation effects during falling BALs were noted in either high-
or low-risk groups, but more high-risk (four) than low-risk
(one) subjects vomited during or shortly after the naltrexone
session. The results of the King study suggest that such
aversive effects of drinking after naltrexone pretreatment
should not be overlooked, even though they were not
statistically significant.
Naltrexone in the Context
of Other Pharmacotherapies
Extensive
recent research has focused on identifying and testing a variety
of drugs to alleviate acute withdrawal symptoms among
alcohol-dependent patients, rapidly induce sobriety or prevent
intoxication, reduce alcohol craving and consumption, and
ameliorate concurrent psychopathology or simultaneous dependence
on illicit drugs. These advances in medications development over
the past 5 years, which reflect neurobiological findings
underlying drinking behavior, are cogently presented in a recent
review (Litten et al., 1996);
some of the most relevant findings are briefly summarized here
regarding medications that are currently available or likely to
be available in the near future. Essentially, researchers now
concur that alcohol consumption is influenced by interactions
among several neurotransmitter systems (e.g., opioid, gamma-aminobutyric
acid [GABA], serotonin, dopamine, glutamate) as well as hormonal
systems.
Other Opioid Antagonists
In
addition to studies of naltrexone, investigators are examining
the efficacy--in reducing the frequency and amount of alcohol
consumption as well as relapse rates--of other opioid
antagonists that have a strong affinity for particular opioid
receptor subtypes. Human studies with nalmefene, an antagonist
with particular affinity for [delta] and [kappa] opioid
receptors and less potential liver toxicity than naltrexone,
have been particularly promising (Litten et al., 1996;
Mason, 1996; Mason et al., 1994).
Animal studies using naltrindole (a [delta] opioid receptor
antagonist) and naltriben (a [delta]2 opioid receptor
antagonist) are also encouraging.
Acamprosate
Acamprosate
(calcium acetylhomotaurinate) is a synthetic derivative of
homotaurine, a structural analogue of GABA, which has yielded
promising results in several European clinical trials with
respect to decreases in drinking and increases in continuous
abstinence or abstemious periods compared with placebo (for a review, see Wilde and
Wagstaff, 1997). Acamprosate appears to be generally
safe and has been shown to have a dose-response effect on
drinking behavior. Treatment duration has varied between 3 and
12 months. A multisite clinical trial to test the efficacy and
safety of acamprosate is currently being conducted in the United
States.
Selective Serotonin
Reuptake Inhibitors
Although
the results of animal studies of SSRIs (e.g., fluoxetine
[Prozac]) indicate that this type of medication reduces
drinking, the effects among problem-drinking and
alcohol-dependent humans have been far less impressive than
those with naltrexone. The demonstrated antidepressant effects
of SSRIs do, however, help in treating comorbid depression among
alcoholics (Kranzler et al., 1995;
Cornelius et al., 1997).
In view of the sharply increasing use of SSRIs to treat a
multitude of disorders, additional research is needed on the
interaction between naltrexone and SSRIs in substance abuse
treatment. The results of two preclinical studies suggest that
agents that alter serotonin function may have some benefit in
combination with naltrexone (Le and Sellers, 1994;
Zink et al., 1997).
Recent preliminary small-sample open-label studies tentatively
suggest that the combination of antidepressant medications and
naltrexone may be useful in reducing drinking in depressed (Salloum et al., 1998)
and nondepressed alcohol-dependent patients (Farren and O'Malley, 1997).
A larger placebo-controlled trial of the use of the SSRI
sertraline to augment the efficacy of naltrexone in nondepressed
alcohol-dependent patients is currently underway.
Serotonin Antagonists/Agonists
Laboratory studies and brief clinical trials of serotonin (5-HT3
and 5-HT2) antagonists have proved mostly disappointing,
although animal models suggest that these antagonists suppress
dopamine release in the mesocorticolimbic system and, by
blocking reward systems, might decrease the desire to drink
alcohol (LeMarquand et al., 1994;
Pettinati, 1996).
Some success has been achieved, however, by using the partial
5-HT1A agonist, buspirone, with patients diagnosed with alcohol
abuse/dependence and collateral anxiety disorders (for
a review, see Malec et al., 1996). When combined with
cognitive behavioral therapy, this medication reduces anxiety
symptoms and increases treatment retention. In addition, it
appears to exert very modest effects on reducing the frequency
of alcohol consumption and the risk of a return to heavy
drinking in these patients (Kranzler and Meyer, 1989).
Tricyclic Antidepressants
Patients
with coexisting alcohol dependence and depression have been
treated with the tricyclic antidepressants desipramine and
imipramine with modest-to-good results in terms of improved mood
and reduced risk of relapse (McGrath et al., 1996;
Mason et al., 1996).
Both antidepressants significantly improved depression and to a
certain extent also reduced drinking behavior.
Directions for Future
Research
Both
the literature and experience from clinical trials suggest that
key areas for additional research on naltrexone treatment are
-
Determining optimal dosing regimens with consideration
for patient acceptance, common adverse effects, efficacy,
and costs
-
Determining the most effective initial duration of
adjunctive naltrexone treatment and the conditions for
extending or resuming use
-
Evaluating the cost-effectiveness of naltrexone treatment
-
Exploring the feasibility and acceptability of inpatient
naltrexone induction to prevent relapse immediately after
detoxification and to determine the potential for increased
efficacy
-
Identifying "responder" subpopulations whose
characteristics (e.g., severity of alcohol-related problems,
comorbid psychopathology or drug dependence, cognitive
impairment, familial history of alcoholism, reported
craving, demographics, general health) predispose them to
successful, adjunctive use of naltrexone either alone or in
combination with other pharmacotherapies
-
Determining necessity for abstinence prior to initiating
naltrexone or the feasibility of using this drug to help
patients gradually reduce their drinking with the goal of
abstinence
-
Determining the effect of naltrexone in alcohol
withdrawal
-
Ascertaining the optimal psychosocial therapies (e.g.,
coping skills training, supportive therapy, cue extinction)
and the intensity and duration with which they need to be
applied for different patient subpopulations receiving
adjunctive naltrexone
-
Ascertaining the drug's effects on both the mother and
fetus during pregnancy, on lactation in the new mother, and
on the breast-feeding infant
-
Researching the use of naltrexone with adolescent and
elderly populations
-
Ascertaining the efficacy of naltrexone in other clinical
populations, including alcoholics in the criminal justice
system, social drinkers with health problems, and heavy
drinkers
-
Determining the effectiveness of naltrexone in general
populations of individuals with alcohol dependence
-
Conducting followup studies of treated populations to
determine drinking-related outcomes at different intervals
following termination of medication
-
Identifying effective strategies for enhancing compliance
with medication administration, including the reduction of
adverse effects, involving collaterals and other monitoring
systems in assuring that medicine is taken as prescribed,
and changing dosing regimens or developing depot
formulations
-
Exploring the efficacy of other opioid receptor-specific
antagonists (e.g., nalmefene)
-
Determining the biological mechanisms of alcohol's
effects on endogenous opioids, the role of the
opioidergic/dopaminergic reward system in alcoholism, and
the relationships among several neurotransmitter systems
that apparently influence drinking behavior
-
Determining the mechanisms responsible for reductions in
drinking behavior over time (e.g., craving, protracted
withdrawal symptoms)
-
Exploring combining naltrexone with other medications,
such as selective serotonin reuptake inhibitors, disulfiram,
and acamprosate
Summary
To
date, most of the clinical studies of naltrexone as an adjunct
to a broad spectrum of psychosocial therapies for
alcohol-dependent or alcohol-abusing patient populations in
brief-to-intensive structured treatment programs have
demonstrated the superiority of this medication over placebo for
reducing
-
The percentage of days spent drinking
-
The amount of alcohol consumed on a drinking occasion
-
Relapse to excessive and destructive drinking
Naltrexone
also appears to significantly reduce the euphoric high
experienced by alcohol-dependent drinkers and social drinkers
who are at risk for becoming dependent because of their familial
history of alcoholism. The effect of naltrexone on reducing the
reinforcing properties of alcohol may help break the addictive
drinking cycle in which one drink leads to another. Over the 6
months after treatment, patients who received naltrexone still
have somewhat better outcomes than those given placebo with
respect to overall relapse rates and drinking-related problems,
although the positive effects of the medication seem to diminish
after termination. However, many clients who continue to use the
information and skills that they obtained and/or developed
during treatment can and do stay sober. Compliance with the
medication regimen and attendance at treatment sessions are both
strong predictors of improved outcomes for populations treated
with naltrexone.
Naltrexone's effect on decreasing alcohol craving is not as
clear: The results of some studies indicate a significant
reduction in this measure from baseline to termination compared
with placebo, whereas others show few or inconsistent medication
effects on the urge to drink, which is notoriously subjective
and difficult to validate. Naltrexone, at a daily dose of 50 mg,
does not appear to be efficacious in reducing alcohol and
cocaine use among the sizable number of alcohol-dependent
patients who simultaneously abuse cocaine. It may have, however,
some efficacy among patients with other comorbid
psychopathologies or at different dosage levels. A number of
treatment-related issues need further exploration and resolution
through additional research.
This
chapter provides a brief overview of naltrexone as a medication,
including its development and clinical role, its mechanism of
action, its pharmacokinetic properties, its safety and common
adverse effects, and some clinical precautions to be used in
prescribing.
Development of Naltrexone
Naltrexone
was approved by the Food and Drug Administration (FDA) in
December 1994 as a potentially important tool in the treatment
of alcohol dependence. At that time, its trade name was changed
from Trexan®, which was first marketed by DuPont Merck
Pharmaceutical Company in 1984 for use in treating opiate
addictions, to ReVia® (Research
Institute of Addictions, 1995). It is not, however, a
new medication. Its history extends back to 1915, when German
scientist Uber J. Pohl documented antagonistic effects of N-allylnorcodeine
on morphine-induced respiratory depression in laboratory
animals. The clinical importance of Pohl's finding was not
pursued until the 1940s with the synthesis of nalorphine, the
first synthetic opioid antagonist. Nalorphine was approved in
1951 for reversing the adverse and life-threatening effects of
opiate overdose as well as for preventing narcotic-induced
respiratory depression in obstetric cases and for diagnosing
narcotic addiction (Gamage and Zerkin, 1973).
The theoretical basis for using opioid antagonists in the
treatment of opiate dependence originated with the
operant-conditioning formulations and experiments of Wikler and
colleagues, beginning in the 1940s and continuing through the
1960s (e.g., Wikler, 1948; Wikler and Pescor, 1967).
These researchers postulated that the euphoria accompanying the
use of heroin and other narcotics reinforces repeated
drug-seeking behavior as physical dependence develops. Once
tolerance develops, the opiate-dependent individual avoids
painful withdrawal symptoms by continuously increasing the
amounts of opiates consumed. Even after addiction is overcome
(i.e., abstinence established), a conditioned abstinence
syndrome can be precipitated by environmental stimuli associated
with the pleasurable effects of drug-taking. Thus, previously
addicted individuals may again experience withdrawal symptoms
when, for example, they return to old neighborhoods where drugs
are available, encounter former "running partners," or
come in contact with needles used to shoot up. These dysphoric
responses are translated into a return of cravings for opiates.
If, however, the researchers hypothesized, an antagonist were
used to block euphoric responses and the development of
dependence, the reinforcing aspects of drug-taking could be
attenuated, and the behavior would abate. Furthermore, if the
antagonist also blocks conditioned responses, the powerful urge
to take drugs again could gradually be decreased. Hence, with
the help of concomitant psychosocial therapy, short-term
administration of an opioid antagonist would give the detoxified
addict time to
-
Test the blockading effects if opiate use is resumed
-
Extinguish "cues" that precipitate
uncomfortable symptoms and craving
-
Resolve problems resulting from addiction
-
Regain some internal controls and personal responsibility
for his or her behavior (Julius
and Renault, 1976; Ginsburg,
1984)
This
enticing theoretical construction prompted a more intensive
search for a clinically acceptable opioid antagonist. The
dysphoric side effects of nalorphine discouraged its use for
this purpose. Cyclazocine--a benzomorphan derivative--was found
to be orally effective and to have relatively long-acting opioid
antagonistic effects, but a number of clinical trials during the
1960s were only partially successful in retaining patients
because the medication also produced dysphoria as well as some
withdrawal symptoms upon termination (Jaffe, 1967).
Naloxone--an allyl derivative of noroxymorphone--was synthesized
in the 1960s and found to be a sufficiently potent opioid
antagonist without the dysphoric side effects. But naloxone's
duration of action after oral administration was found to be too
short for clinical utility--24-hour blockade against a 50-mg
challenge dose of heroin could not be achieved with 1,500 mg
naloxone (Julius and Renault, 1976;
Ginsburg, 1984; Gonzalez and Brogden, 1988).
By comparison, naltrexone, which was also synthesized in the
1960s, was found to have several properties necessary for
clinical utility in the treatment of opioid dependence:
Naltrexone
is at least 17 times more potent than nalorphine in
morphine-dependent humans and twice as potent as naloxone in
precipitating withdrawal symptoms. A 100-mg oral dose of
naltrexone given to abstinent addicts yielded a 90-percent
blockade of subjective euphoria and other objective responses to
intravenous heroin challenge at 24 hours, with antagonism to
subsequent heroin challenges decreasing over 72 hours (Gonzalez
and Brogden, 1988).
After encouraging findings in preclinical studies, naltrexone
was extensively tested in clinical trials supported and
encouraged by the new Special Action Office for Drug Abuse
Prevention (SAODAP), a part of the Executive Office of the
President that was created by Congress in the midst of a
"heroin epidemic" and intense public pressure to solve
the social and criminal problems stemming from drug addiction.
In fact, the legislation that established SAODAP--a precursor to
the National Institute on Drug Abuse (NIDA)--contained a special
section and appropriations specifically targeted at the
development of opioid antagonists (Julius and Renault, 1976).
Unfortunately, the promising expectations for naltrexone's
efficacy and clinical utility in treating opiate dependence have
not yet been fulfilled. NIDA, however, is currently studying
ways to improve the effectiveness of naltrexone for treating
opiate dependence.
Both controlled and noncomparative studies confirmed that
naltrexone reduces heroin and other opiate self-administration
and craving in detoxified opiate addicts, but attrition rates in
most of these trials were very high, with many of the medicated
subjects discontinuing naltrexone and relapsing to illicit
opiate abuse (see Ginsburg,
1984; Gonzalez
and Brogden, 1988; Julius and Renault, 1976;
Mello et al., 1981).
Highly motivated patients (e.g., professionals who had
"everything to lose") were found to benefit most from
naltrexone treatment, especially if medication was combined with
strong family support and intensive, supportive psychotherapy (Gonzalez
and Brogden, 1988). Because few "street
addicts" met the screening criteria recommended for
naltrexone treatment (i.e., employed, married, highly motivated
to use nonopioid chemotherapy, and able to remain opiate-free
for 5 to 10 days following withdrawal) and most abused more than
one class of drugs, naltrexone only proved to be attractive to
or effective for a limited cohort of patients who could be
treated by knowledgeable treatment professionals.
Many of the findings from these NIDA-supported studies of
naltrexone for the treatment of opiate dependence informed the
clinical trials of the same drug for treating alcohol-dependent
subjects. Notably, naltrexone--even in combination with
psychosocial treatment--does not cure dependency. Clients must
learn to be abstinent, avoid relapse, and improve their quality
of life. Naltrexone is but one tool in a larger therapeutic
regimen that must include individually tailored psychosocial
therapy and rehabilitation focused on addiction-associated
problems (Ginsburg, 1984).
Pharmacological Properties
Pharmacodynamics
Naltrexone
hydrochloride--a relatively pure and long-lasting opioid
antagonist--is a synthetic congener of oxymorphone with
negligible opioid agonist properties (i.e., some pupillary
constriction has been reported in isolated cases) (Gonzalez and Brogden,
1988). Naltrexone's major effects are produced by the
parent drug
(17-(cyclopropylmethyl)-4,5-epoxy-3,14-dihydroxymorphinan-6-one)
and its primary metabolite (6-beta-naltrexol). By binding
competitively at opioid receptor sites within the central
nervous system (primarily the brain), naltrexone prevents the
stimulation of opioid receptors and thereby attenuates or
completely blocks the usual euphoria-causing and physical
dependence-producing responses. If opiates are already present
(i.e., bound at receptor sites), then naltrexone displaces them
almost immediately and precipitates such well-known withdrawal
symptoms as anxiety, irritability, yawning, runny eyes and nose,
perspiration, vomiting, cramps, tremors, and insomnia. If
opiates are administered after naltrexone consumption, then the
antagonist blocks both the pleasurable feelings and, with
regular administration at sufficient doses, the development of
physical dependence.
Pharmacokinetics
Dosing, administration, and
tolerance
Clinical
studies have shown that a 50-mg oral dose of naltrexone will
block the pharmacological effects of a 25-mg dose of
intravenously administered heroin for up to 24 hours. The
results of other studies show that doubling the dose of
naltrexone to 100 mg will block effects for up to 48 hours, and
tripling the dose will block effects for up to 72 hours (PDR, 1997).
Flexible dosing schedules used in the clinical trials of
naltrexone with opiate addicts have been acceptable to most
patients and have proven equally satisfactory in other treatment
settings. Dosing schedules have included regimens of 50 mg
naltrexone on weekdays, with 100 mg on Saturday; 100 mg on
Monday and Wednesday, with 150 mg on Friday; 150 mg on Monday
and 200 mg on Thursday; or 150 mg every third day (Ginsburg,
1984; Gonzalez
and Brogden, 1988). These schedules are typically
used to make it easier for programs to supervise (i.e., observe)
naltrexone ingestion in order to enhance medication compliance.
Naltrexone administration is not associated with the development
of tolerance or dependence, and there are no withdrawal effects
upon termination of naltrexone treatment (Addiction
Research Foundation [ARF], 1996). Although the
long-term effects of naltrexone are, as yet, not well
documented, some research has shown that tolerance to the
antagonist properties of naltrexone does not develop when
administered for up to 21 months (Gonzalez and Brogden, 1988;
ARF, 1996).
A double-blind, placebo-controlled study of naltrexone for
treatment of opiate addicts found that 20 to 40 mg intravenous
challenge doses of morphine administered after subjects had been
taking naltrexone for a mean of 9.4 months produced dysphoric,
histamine-like responses (Gonzalez and Brogden,
1988).
Alcohol-dependent persons who consume small-to-moderate amounts
of alcohol while taking naltrexone may experience less euphoria
than usual, but they will not have adverse, dangerous physical
reactions to alcohol as seen with disulfiram. Naltrexone,
however, does not prevent the impairment-causing effects of
alcohol (e.g., loss of coordination, inability to exercise good
judgment) and does not decrease blood alcohol levels resulting
from drinking (Swift et al., 1994).
Absorption and
bioavailability
Orally
administered naltrexone is rapidly and nearly completely
absorbed in the gastrointestinal tract (96 percent). Peak plasma
concentrations of naltrexone (19 to 44 mg/L) and its primary
metabolite 6-beta-naltrexol occur within 1 hour of dosing (Gonzalez
and Brogden, 1988; PDR,
1997). Oral bioavailability estimates range from 5 to
60 percent (Gonzalez and Brogden,
1988).
Distribution
The
volume of distribution for naltrexone following intravenous
administration is estimated to be 1,350 liters. In vitro tests
with human plasma show naltrexone to be 20 percent bound to
plasma protein over the therapeutic dose range (PDR, 1997).
There is no evidence of naltrexone accumulation in healthy
subjects after multiple 100-mg daily doses (Gonzalez and Brogden,
1988). Both naltrexone and 6-beta-naltrexol are dose
proportional in terms of Cmax (maximum concentrations) for the
AUC (area under the curve) over the range of 50 to 200 mg (PDR,
1997).
Metabolism
The
major metabolic pathway entails reduction of naltrexone to its
major metabolite 6-beta-naltrexol, minor metabolites (e.g.,
2-hydroxy-3-methoxy-6-beta-naltrexol and
2-hydroxy-3-methyl-naltrexone), and other metabolic products (Gonzalez and Brogden, 1988;
PDR, 1997).
Naltrexone is subject to significant first-pass metabolism in
the liver, resulting in only an estimated 5 percent of the
unchanged drug reaching the systemic circulation (Ginsburg, 1984; Gonzalez and Brogden, 1988).
The systemic clearance (after intravenous administration) of
naltrexone is approximately 3.5 L/min, which exceeds liver blood
flow of approximately 1.2 L/min. This suggests both that
naltrexone is a highly extracted drug (>98 percent
metabolized) and that extrahepatic sites of metabolism exist.
The mean elimination half-life values for naltrexone and the
6-beta-naltrexol metabolite are, respectively, 4 hours and 13
hours.
Early research demonstrated considerable individual variability
in the metabolism of naltrexone. For example, in one study of
acute and chronic administration of naltrexone, there was a
three- to fourfold difference across subjects in peak
6-$-naltrexol levels, ranging from 83 to 288 ng/mL (Verebey et al., 1976).
Findings also showed that narcotic antagonism was highly
correlated with naltrexone plasma levels (r = .90). These early
studies concluded that different individual biotransformation
rates would be expected to influence the time course and
magnitude of naltrexone blockade effects (Verebey, 1980).
Excretion
Both
the parent drug and its metabolites are primarily excreted by
the kidney (53 to 79 percent of the dose). Urinary excretion of
unchanged naltrexone accounts for less than 2 percent of an oral
dose, and fecal excretion is a minor elimination pathway.
Urinary excretion of unchanged and conjugated 6-beta-naltrexol
accounts for 43 percent of an oral dose. The renal clearance for
naltrexone ranges from 30 to 127 mL/min, suggesting that renal
elimination is primarily by glomerular filtration; the renal
clearance for 6-beta-naltrexol ranges from 230 to 369 mL/min,
which suggests an additional renal tubular secretory mechanism (Ginsburg, 1984; PDR, 1997).
Safety and Common Adverse
Effects
Naltrexone
appears to be clinically safe, with a low incidence of common
adverse effects and no clinically significant changes in
laboratory values among subjects being treated for opiate or
alcohol dependency. Many of the adverse reactions and
abnormalities that have been reported are common among patients
for whom the drug is prescribed and have not occurred
significantly more frequently in medicated cohorts compared with
those receiving placebo (Ginsburg, 1984; PDR, 1997).
Prior to the FDA's initial approval of naltrexone as a treatment
for opiate addiction, several studies showed naltrexone to be a
safe, nontoxic medication in the single dosage range of 20 to
160 mg (Gritz et al., 1976;
Julius and Renault, 1976; Judson et al., 1981; Mello et al., 1981).
These findings have been supported in the more recent clinical
trials of naltrexone as an adjunct for the treatment of alcohol
dependence (Volpicelli et al., 1992;
O'Malley et al., 1992;
Croop et al., 1997).
Toxicity
No
toxicity was found following daily administration of doses of up
to 800 mg of naltrexone for a week (PDR,
1997).
Carcinogenesis
Animal
studies have not found any carcinogenic responses to 2-year
administration of naltrexone to rats (Gonzalez
and Brogden, 1988; PDR,
1997).
Liver Damage
One
of the most serious potential adverse effects of naltrexone is
liver toxicity. High doses of naltrexone administered to obese
patients (up to 300 mg/day or five times more than an effective
blockading dose of 50 mg/day) have been found to produce
hepatocellular injury in a substantial portion of exposed
subjects (Gonzalez and Brogden,
1988). Although some of the obese patients in this
study had mild abnormalities of liver function at baseline,
elevated levels of serum aminotransferases returned to baseline
or normal within a short time after termination of naltrexone
treatment. It is important to note, however, that liver
abnormalities are common among obese patients and those who are
opiate- or alcohol-dependent (Gonzalez and Brogden,
1988).
High doses of naltrexone administered for treatment of
Huntington's disease (up to 300 mg/day for up to 36 months)
produced transient increases in serum aminotransferases (serum
glutamic-oxaloacetic transaminase [SGOT] and serum
glutamic-pyruvic transaminase [SGPT]) in 2 of 10 patients, but
these elevations returned to baseline with continued treatment (Sax et al., 1994).
These investigators concluded that chronic administration of
naltrexone in doses up to 300 mg/day for periods up to 36 months
does not significantly change hepatic function as measured by
SGOT and SGPT levels.
In a more recent safety study of 570 heterogeneous
alcohol-dependent patients (Croop et al., 1997),
LFT results were similar to a comparison group of 295 patients
who did not receive naltrexone (see below for further details of
this study).
In the first clinical trial of naltrexone for the treatment of
alcohol dependence, the medication was actually associated with
lower levels of liver enzymes in the normal range compared with
those of placebo-treated participants (Volpicelli et al., 1992,
1995a). Similar
results were found in the second trial: Endpoint levels of
aspartate aminotransferase and alanine aminotransferase were
lower for the naltrexone-medicated subjects than for
placebo-treated participants (O'Malley et al., 1992).
Another study of heavy drinkers treated with naltrexone reported
improved hepatic enzyme levels that were consistent with these
earlier findings (Bohn et al., 1994).
Better hepatic function in naltrexone-treated patients compared
with placebo-treated patients is probably a reflection of
reduced drinking among those receiving naltrexone, because
alcohol is a known hepatotoxin.
Weight Reduction
Studies
with small samples of naltrexone-treated subjects have noted
some significant weight loss (Atkinson,
1984). Self-reports of weight loss were more common
among naltrexone-treated patients than among placebo-treated
patients (O'Malley et al., 1992).
However, a 10-week, placebo-controlled trial with obese
patients, using 50 to 300 mg daily doses of naltrexone, did not
find any reduction in caloric intake or weight loss (Gonzalez
and Brogden, 1988). A clinical trial of naltrexone
plasma levels, clinical response, and effect on weight in
autistic children found that although children in the highest
weight percentile had a tendency to lose weight while taking
naltrexone, none of the other children in the study were
affected (Gonzalez et al., 1994).
Other Common Adverse
Physiological Effects
Initial
trials of naltrexone for treatment of opiate dependence found
the medication to be well tolerated by most subjects, with few
common adverse effects. The specific symptoms occurring more
frequently in medicated patients than in placebo-treated
controls participating in the first five double-blind trials
included loss of appetite, nausea, vomiting, abdominal cramps,
and constipation (Julius and
Renault, 1976). A double-blind study comparing the
efficacy of thrice-weekly 60- and 120-mg doses of naltrexone for
opiate-dependent subjects found that neither toxicity nor
complaints about side effects were significantly different from
those in earlier studies using smaller (e.g., 50 mg) daily doses
of naltrexone. Virtually all of the reported side effects seemed
to mimic those of opiate withdrawal (e.g., gastrointestinal
complaints) and decreased over the first 3 weeks of treatment (Judson et al., 1981).
Similar results have been found in the initial trials of
naltrexone for treatment of alcohol dependence. The few reported
physiological side effects, which are usually short-lived,
primarily pertain to nausea, vomiting, headache, increased
sexual desire, and increased anxiety and agitation (Volpicelli et al., 1992,
1995b). O'Malley
and colleagues (O'Malley
et al., 1992) found that naltrexone-treated patients
experienced more nausea and reported more weight loss and
dizziness than did subjects receiving placebo. The complaints
usually followed the initial medication dose. A recent study of
naltrexone as an adjunct to standard alcoholism treatment in a
community clinic setting found that increased sexual desire was
the only medication effect reported more frequently by the
medicated patients compared with those taking placebo (Volpicelli et al., 1997).
Overall, the common adverse effects of naltrexone have been
severe enough to discontinue medication for 5 to 10 percent of
alcohol-dependent patients who began taking the medication (Volpicelli et al., 1992;
O'Malley et al., 1992;
Croop et al., 1997).
A 3-month, open-label study sponsored by the DuPont Merck
Pharmaceutical Company examined a heterogeneous sample of 570
naltrexone-treated alcohol-dependent men and women and 295
nonmedicated and nonrandomized controls to determine the safety
and common adverse effects of this medication when taken for 3
to 6 months (Croop et al., 1997).
The most common new-onset adverse events in the naltrexone group
included nausea (9.8 percent) and headaches (6.6 percent). Other
reported adverse effects included dizziness (4 percent), fatigue
(4 percent), insomnia (3 percent), anxiety and nervousness (2
percent), and sleepiness (2 percent). In addition, a few
patients reported abdominal pain and cramps, vomiting, low
energy, and joint and muscle pain. Liver function test results
were similar to those seen in the nonmedicated group. No
unexpected adverse events were seen in this heterogeneous sample
of individuals with alcohol dependence. This study is the
largest to date describing the safety of naltrexone in a
heterogeneous population of individuals with alcoholism. The
investigators concluded that no new safety concerns were
identified.
Common Adverse
Psychological Effects
Naltrexone
usually has no adverse psychological effects, and patients who
take the drug do not report being either "high" or
"down" while they are on this medication. Although it
does seem to reduce alcohol craving, naltrexone is thought not
to interfere with the experience
of other types of pleasure (Dillon
and Homer, 1995). Although two studies have assessed
the psychological side effects of naltrexone (Gritz et al., 1976;
Volpicelli et al., 1992),
only the Gritz et al. study reported significant medication
effects compared with placebo: (1) facilitation of attention and
perception, as measured on the Cross-Out Test; and (2) mild
euphoria, as measured on the Addiction Research Center
Inventory.
Although further research is needed on many aspects of
naltrexone's use, the evidence thus far is encouraging.
Naltrexone appears to target the parts of the brain involved in
alcohol abuse accurately and cleanly. The information in this
TIP will help providers use this medication to better treat
their patients who have alcohol use disorders.
[Back Matter]
Addiction
Research Foundation (ARF).
Fast
Fax Facts on Naltrexone. Toronto, Ontario, Canada: Addiction
Research Foundation, January 1996.
Alcoholics
Anonymous, 3rd ed.
New
York: Alcoholics Anonymous World Services, Inc., 1976.
Allan,
A.M., and Harris, R.A.
Acute
and chronic ethanol treatments alter GABA receptor-operated
chloride channels. Pharmacology, Biochemistry and Behavior
27:665-670, 1987.
American
Psychiatric Association.
Diagnostic
and Statistical Manual of Mental Disorders, 3rd ed., revised
(DSM-III-R), Washington, DC : American Psychiatric Association,
1987.
American
Society of Addiction Medicine.
Patient
Placement Criteria for the Treatment of Substance-Related
Disorder, 2nd ed. Chevy Chase, MD: American Society of Addiction
Medicine, 1996.
Annis, H.M.,
and Peachy Peachey, J.E.
The
use of calcium carbimide in relapse prevention counseling
counseling: Results of a randomized controlled trial. British
Journal of Addiction 87:63-72, 1992.
Anton, R.F.
New
directions in the pharmacotherapy of alcoholism. Psychiatric
Annals 25:353-362, 1995.
Anton, R.F.
Naltrexone
as Adjunctive Treatment to Cognitive Behavioral Therapy for
Outpatient Alcoholics. Paper presented at the annual meeting of
the American College of Neuropsychopharmacology, Waikoloa,
Hawaii, December 1997.
Anton, R.F.;
Moak, D.H.; and Latham, P.K.
The
obsessive compulsive drinking scale: A new method of assessing
outcome in alcoholism treatment studies. Archives of General
Psychiatry 53(3):225-231, 1996.
Atkinson,
R.L.
Endocrine
and metabolic effects of opiate antagonists. Journal of Clinical
Psychiatry 45(9):20B24, 1984.
Bien, T.;
Miller, W.; and Tonigan, J.
Brief
interventions for alcohol problems: A review. Addiction
88(3):315-335, 1993.
Bohn, M.J.;
Krahn, D.D.; and Staehler, B.A.
Development
and initial validation of a measure of drinking urges in
abstinent alcoholics. Alcohol Clinical and Experimental Research
19(3):600-606, 1995.
Bohn, M.J.;
Kranzler, H.R.; Beazoglou, D.; and Staehler, B.A.
Naltrexone
and brief counseling to reduce heavy drinking. American Journal
of the Addictions 3:91-99, 1994.
Bray, J.H.,
and Rogers, J.C.
Linking
psychologists and family physicians for collaborative practice.
Professional Psychology: Research and Practice 26:132-138,1995.
Carroll,
K.; Ziedonis, D.; O'Malley, S.S.; McCance-Katz, E.; Gordon, L.;
and Rounsaville, B.
Pharmacologic
interventions for alcohol- and cocaine-abusing individuals: A
controlled study of disulfiram vs. naltrexone. American Journal
on Addictions 2:77-79, 1993.
Center for
Substance Abuse Treatment (CSAT).
Detoxification
from Alcohol and Other Drugs. Treatment Improvement Protocol
(TIP) Series, Number 19. DHHS Publication No. (SMA) 95-3046.
Washington, DC: U.S. Government Printing Office, 1995.
Center for
Substance Abuse Treatment (CSAT).
Substance
Abuse Treatment and Domestic Violence. Treatment Improvement
Protocol (TIP) Series, Number 25. DHHS Publication No. (SMA)
97-3163. Washington, DC: U.S. Government Printing Office, 1997.
Charness,
M.E.
Alcohol
and the brain. Alcohol Health and Research World 14(2):85-89,
1990.
Charness,
M.E.; Hu, G.; Edwards, R.H.; and Querimit, L.A.
Ethanol
increases delta-opioid receptor gene expression in neuronal cell
lines. Molecular Pharmacology 44:1119-1127, 1993.
Charness,
M.E.; Querimit, L.A.; and Diamond, I.
Ethanol
increases the expression of functional delta-opioid receptors in
the neuroblastoma X glioma NG108-15 hybrid cells. Journal of
Biologic Chemistry 261:3164-3169, 1986.
Cloninger,
C.R.
Recent
advances in family studies of alcoholism. Progress in Clinical
and Biological Research 241:47-60, 1987.
Cloninger,
C.R.
Etiologic
factors in substance abuse: An adoption study perspective. In:
Pickens, R.W., and Svikis, D.S., eds. Biological Vulnerability
to Drug Abuse. NIDA Research Monograph Series, Number 89.
Rockville, MD: National Institute on Drug Abuse, 1988. pp.
52-72.
Cornelius,
J.R.; Salloum, I.M.; Ehler, J.G.; Jarrett, P.J.; Cornelius,
M.D.; Perel, J.M.; Thase, M.E.; and Black, A.
Fluoxetine
in depressed alcoholics: A double-blind, placebo-controlled
trial. Archives of General Psychiatry 54:700-705, 1997.
Croop, R.S.,
and Chick, J.
American
and European clinical trials of naltrexone. In: Litten, R.Z.,
and Fertig, J. (chairs), International Update: New Findings on
Promising Medications. Alcoholism: Clinical and Experimental
Research 20(8 suppl.):216A-218A, 1996.
Croop, R.S.;
Faulkner, E.B.; and Labriola, D.F., for the Naltrexone Usage
Study Group.
The
safety profile of naltrexone in the treatment of alcoholism:
Results from a multicenter usage study. Archives of General
Psychiatry 54(12):1130-1135, 1997.
Croop, R.S.;
Labriola, D.F.; Wroblewski, J.M.; and Nibbelink, D.W.
A
Multicenter Safety Study of Naltrexone as Adjunctive
Pharmacotherapy for Individuals with Alcoholism. Paper presented
at the American Psychiatric Association's 148th annual meeting
in Miami, May 20-25, 1995.
Davidson,
D.; Swift, R.; and Fitz, E.
Naltrexone
increases the latency to drink alcohol in social drinkers.
Alcoholism: Clinical and Experimental Research 20:732-739, 1996.
deWaele,
J.P.; Papachristou, D.N.; and Gianoulakis, C.
The
alcohol-preferring C57-L/6 mice present an enhanced sensitivity
of the hypothalmic b-endorphin system to ethanol than the
alcohol-avoiding DBA/2 mice. Journal of Pharmacology and
Experimental Therapeutics 281:788-794, 1992.
Di Chiara,
G.
Alcohol
and dopamine. Alcohol Health and Research World 21(2):108-114,
1997.
Dillon,
D., and Homer, A.L.
Answers
to frequently asked questions about naltrexone treatment for
alcoholism. In: Rounsaville, B.J.; O'Malley, S.; and O'Conner,
P., eds. Guidelines for the Use of Naltrexone in the Treatment
of Alcoholism. New Haven, CT: APT Foundation, 1995.
Doty, P.,
and deWit, H.
Effects
of naltrexone pretreatment on the subjective and performance
effects of ethanol in social drinkers. Behavioral Pharmacology
6:386-394, 1995.
Doyle, R.
Deaths
due to caused by alcohol. Scientific American, Dec. 1996http://www.health.org/pressrel/alcart.htm
[Accessed Nov. 6, 1997].
DuPont
Pharma.
Product
Monograph: ReVia (naltrexone HCl). 1995.
Farren,
C.K., and O'Malley, S.
Sequential
use of naltrexone in the treatment of relapsing alcoholism.
American Journal of Psychiatry154(5):714, 1997.
Fleming,
M.F., and Barry, K.L.
Clinical
overview of alcohol and drug disorders. In: Fleming, M.F., and
Barry, K.L., eds. Addictive Disorders. Chicago: Mosby Yearbook,
1992. pp. 3-21.
Froehlich,
J.C.
Genetic
factors in alcohol self-administration. Journal of Clinical
Psychiatry 56(suppl. 7):15-23, 1995.
Froehlich,
J.C.
The
neurobiology of ethanol-opioid interactions in ethanol
reinforcement. Alcoholism: Clinical and Experimental Research
20:181A-186A, 1996.
Froehlich,
J.C.
Opioid
peptides. Alcohol Health and Research World 21(2):132-135, 1997.
Froehlich,
J.C., and Li, T.-K.
Opioid
peptides. In: Galanter, M., ed. Recent Developments in
Alcoholism: Volume 11. Ten Years of Progress. New York: Plenum
Press, 1993. pp. 187-205.
Froehlich,
J.C., and Wand, G.
The
neurobiology of ethanol-opioid interactions in ethanol
reinforcement. Alcoholism: Clinical and Experimental Research
20(8)181A-186A, 1996.
Frye, G.D.,
and Breese, G.R.
GABAergic
modulation of ethanol-induced motor impairment. Journal of
Pharmacology and Experimental Therapeutics 223:750-756, 1982.
Gamage,
J.R., and Zerkin, E.L.
Narcotic
Antagonists. National Clearinghouse for Drug Abuse Information
Report Series 26, No. 1, October 1973.
Gianoulakis,
C., and Angelogianni, P.
Characterization
of beta-endorphin peptides in the spinal cord of the rat.
Peptides 10(5):1049-1054, 1989.
Gianoulakis,
C.; Angelogianni, P.; Meany, M.; Thavundayil, J.; and Thawar, V.
Endorphins
in individuals with high and low risk for development of
alcoholism. In: Reid, L.D., ed. Opioids, Bulimia, and Alcohol
Abuse and Alcoholism. New York: Springer-Verlag, 1990. pp.
229-246.
Gianoulakis,
C., and Barcomb, A.
Effect
of acute ethanol in vivo and in vitro on the beta-endorphin
system in the rat. Life Sciences 40(1):19B28, 1987.
Gianoulakis,
C.; Krishnan, B.; and Thavundayil, J.
Enhanced
sensitivity of pituitary beta-endorphin to ethanol in subjects
at high risk of alcoholism. Archives of General Psychiatry
53:250-257, 1996.
Ginsburg,
H.M.
Naltrexone:
Its Clinical Utility. Treatment Research Report, DHHS
Publication No. (ADM) 84-1358. Bethesda, MD: National Institute
on Drug Abuse, 1984.
Goodwin,
D.W.; Schulsinger, F.; Hermansen, L.; Guze, S.D.; and Winokur,
G.
Alcohol
problems in adoptees raised apart from alcoholic biological
parents. Archives of General Psychiatry 28:238-243, 1973.
Gonzales,
R.A., and Jaworski, J.N.
Alcohol
and glutamate. Alcohol Health and Research World 21(2):120-126,
1997.
Gonzalez,
J.P., and Brogden, R.N.
Naltrexone:
A review of its pharmacodynamic and pharmacokinetic properties
and therapeutic efficacy in the management of opioid dependence.
Drugs 35:192-213, 1988.
Gonzalez,
N.M.; Campbell, M.; Small, A.M.; Shay, J.; Bluhm, L.D.; Adams,
P.B.; and Foltz, R.L.
Luteinizing
hormone regulators: Luteinizing hormone releasing hormone
analogs, estrogens, opiates, and estrogen-opiate hybrids.
Psychopharmacology Bulletin 30(2):203-208, 1994.
Grant,
B.F.
DSM-II-R
and proposed DSM-IV alcohol abuse and dependence, United States,
1988: A nosological comparison. Alcoholism: Clinical and
Experimental Research 16(6):1068-1077, 1992.
Gritz, E.R.;
Shiffman, S.M.; Jarvik, M.E.; Schlesinger, J.; and Charuvastra,
V.C.
Naltrexone:
Physiological and psychological effects of single doses.
Clinical Pharmacology and Therapeutics 19:773-776, 1976.
Hiller-Sturmhöfel,
S.
Signal
transmission among nerve cells. Alcohol Health and Research
World 19(2):128, 1995.
Ho, A.K.S.;
Chen, R.C.A.; and Morrison, J.M.
Interactions
of narcotics, narcotic antagonists, and ethanol during acute,
chronic, and withdrawal states. Annals of the New York Academy
of Sciences 281:297-310, 1976.
Institute
for Health Policy, Brandeis University.
Substance
Abuse: The Nation's Number One Health Problem: Key Indicators
for Policy. Princeton, NJ: The Robert Wood Johnson Foundation,
1993.
Institute
of Medicine.
Broadening
the Base of Treatment for Alcohol Problems. Washington, DC:
National Academy Press, 1996.
Jaffe, J.H.
Cyclazocine
in the treatment of narcotic addiction. Current Psychiatric
Therapies 7:147-156, 1967.
Jaffe, A.J.;
Rounsaville, B.; Chang, G.; Schottenfeld, R.S.; Meyer, R.E.; and
O'Malley, S.S.
Naltrexone,
relapse prevention, and supportive therapy with alcoholics: An
analysis of patient treatment matching. Journal of Consulting
and Clinical Psychology 64:1044-1053, 1996.
Jenab, S.,
and Inturrisi, C.E.
Ethanol
and naloxone differentially upregulate delta opioid receptor
gene expression in neuroblastoma hybrid (NG108-15) cells.
Molecular Brain Research 27:95-102, 1994.
Judson,
B.A.; Carney, T.M.; and Goldstein, A.
Naltrexone
treatment of heroin addiction: Efficacy and safety in a
double-blind dosage comparison. Drug and Alcohol Dependence
7:325-346, 1981.
Julius,
D., and Renault, P., eds.
Narcotic
Antagonists: Naltrexone Progress Report. NIDA Research Monograph
Series, Number 9. DHEW Publication No. (ADM) 76-387. Bethesda,
MD: National Institute on Drug Abuse, 1976.
Keith, L.D.;
Crabbe, J.C.; Robertson, L.M.; and Kendall, J.W.
Ethanol
stimulated endorphin and corticotropin in vitro. Brain Research
367(1-2):222-229, 1986.
King, A.C.;
Volpicelli, J.R.; Frazer, A.; and O'Brien, C.P.
Effect
of naltrexone on subjective alcohol response in subjects at high
and low risk for future alcohol dependence. Psychopharmacology
129:15-22, 1997.
Koob, G.F.,
and LeMoal, M.
Drug
abuse: Hedonic homeostatic dysregulation. Science
278(5335):52-58, 1997.
Koob, G.F.;
Rassnick, S.; Heinrichs, S.; and Weiss, F.
Alcohol:
The reward system and dependence. In: Jansson, B.; Jörnvall,
H.; Rydberg, U.; Terenius, L.; and Vallee, B.L., eds. Toward a
Molecular Basis of Alcohol Use and Abuse, Boston:
Birkhauser-Verlag, 1994. pp. 103-114.
Kranzler,
H.R.; Burleson, J.A.; Korner, P.; Del Boca, F.K.; Bohn, M.J.;
Brown, J.; and Liebowitz, N.
Placebo-controlled
trial of fluoxetine as an adjunct to relapse prevention in
alcoholics. American Journal of Psychiatry 152:391-397, 1995.
Kranzler,
H.R., and Meyer, R.E.
An
open trial of buspirone in alcoholics. Journal of Clinical
Psychopharmacology 9(5):379-380, 1989.
Kranzler,
H.R.; Tennen, H.; Penta, C.; and Bohn, M.J.
Targeted
naltrexone treatment of early problem drinkers. Addictive
Behavior 22(3):431-436, 1997.
Kuhar, M.J.
Basic
Neurobiological Research: 1989-1991. Drug Abuse and Drug Abuse
Research: Fourth Triennial Report to Congress from the
Secretary, Department of Health and Human Services. Rockville,
MD: National Institute on Drug Abuse, 1991 (unpublished
document).
Le, A.D.,
and Sellers, E.M.
Interaction
between opiate and 5-HT3 receptor antagonists in the regulation
of alcohol intake. Alcohol and Alcoholism 29(suppl. 2):545-549,
1994.
LeMarquand,
D.; Pihl, R.O.; and Benkelfat, C.
Serotonin
and alcohol intake, abuse, and dependence: Clinical evidence.
Biological Psychiatry 36(5):326-337, 1994.
Leshner,
A.I.
Addiction
is a brain disease, and it matters. Science 278(5335):45-47,
1997.
Li, X.-W.;
Li, T.-K.; and Froehlich, J.C.
Alcohol
alters preproenkephal in mRNA content in the shell and the core
of the nucleus accumbens. Alcoholism: Clinical and Experimental
Research 20:53A, 1996.
Liljequest,
Liljequist S., and Engel, J.
Effects
of GABAergic agonists and antagonists on various ethanol-induced
behavioral changes. Psychopharmacology 78:71-75, 1982.
Litten,
R.Z.; Allen, J.; and Fertig, J.
Pharmacotherapies
for alcohol problems: A review of research with focus on
developments since 1991. Alcoholism: Clinical and Experimental
Research 20:859-876, 1996.
Little,
H.J.
Mechanisms
that may underlie the behavioral effects of ethanol. Progress in
Neurobiology 36:171-194, 1991.
Lozano
Polo, J.L.; Gutierrez Mora, E.; Martinez Perez, V.; Santamaria
Gutierrez, J.; Vada Sanchez, J.; and Vallejo Correas, J.A.
[Effect
of methadone or naltrexone on the course of transaminase[s] in
parenteral drug users with hepatitis C virus infection.] Revista
Clinica Espanola 197(7):479-483, 1997.
Malec, T.S.;
Malec, E.A.; and Doniger, M.
Efficacy
of buspirone in alcohol dependence: A review. Alcoholism:
Clinical and Experimental Research 20(5):853-858, 1996.
Mason, B.J.
Dosing
issues in the pharmacotherapy of alcoholism. Alcohol: Clinical
and Experimental Research 20(suppl. 7):10A-16A, 1996.
Mason, B.J.;
Kocsis, J.H.; Ritvo, E.C.; and Cutler, R.B.
A
double-blind, placebo-controlled trial of desipramine for
primary alcohol dependence stratified on the presence or absence
of major depression. Journal of the American Medical Association
275:761-767, 1996.
Mason, B.J.;
Ritvo, E.C.; Morgan, R.O.; Salvato, F.R.; Goldberg, G.; Welch,
B.; and Mantero-Atienza, E.
A
double-blind, placebo-controlled pilot study to evaluate the
efficacy and safety of oral nalmefene HCl for alcohol
dependence. Alcohol: Clinical and Experimental Research
18(5):1162-1167, 1994.
Maxwell,
S., and Shinderman, M.
Naltrexone
in the Treatment of Alcohol-Dependent, Mentally Ill Patients: A
Retrospective Analysis of 83 Cases. Paper presented at the
annual meeting of the American Society of Addiction Medicine,
San Diego, California, April 1997.
McBride,
W.J.; Murphy, J.M.; Yoshimoto, K.; Lumeng, L.; and Li, T.-K.
Serotonin
mechanisms in alcohol drinking behavior. Drug Development
Research 30:170-177, 1993.
McCaul,
M.E.
Efficacy
of naltrexone for alcoholics with and without comorbid opiate or
cocaine dependence. In: Litten, R.Z., and Fertig, J., Chairs.
International Update: New Findings on Promising Medications.
Alcoholism: Clinical and Experimental Research
20(suppl.):216A-218A, 1996.
McGrath,
P.J.; Nunes, E.V.; Stewart, J.W.; Goldman, D.; Agosti, V.;
Ocepek-Welikson, K.; and Quitkin, F.M.
Imipramine
treatment of alcoholics with primary depression: A
placebo-controlled clinical trial. Archives of General
Psychiatry 53(3):232-240, 1996.
Mello, N.K.;
Mendelson, J.H.; Kuehnle, J.C.; and Sellers, M.S.
Operant
analysis of human heroin self-administration and the effects of
naltrexone. Journal of Pharmacology and Experimental
Therapeutics 216:45-54, 1981.
Mihic, S.J.,
and Harris, R.A.
GABA
and the GABAA receptor. Alcohol Health and Research World
21(2):127-131, 1997.
Miller,
W.R., and Hester, R.K.
Inpatient
alcoholism treatment: Who benefits? American Psychologist
41(7):794-805, 1986.
Naranjo,
C.A.; Kadlec, K.E.; Sanhueza, P.; Woodley-Remus, D.; and
Sellers, E.M.
Fluoxetine
differentially alters alcohol intake and other consummatory
behaviors in problem drinkers. Clinical Pharmacology and
Therapeutics 47:490-498, 1990.
Naranjo,
C.A.; Sellers, E.M.; Roach, C.A.; Woodley, D.V.; Sanchez-Craig,
M.; and Sykora, K.
Zimelidine-induced
variations in alcohol intake in non-depressed heavy drinkers.
Clinical Pharmacology and Therapeutics 35:374-381, 1984.
Naranjo,
C.A.; Sellers, E.M.; Sullivan, J.T.; Woodley, D.V.; Kadlec, K.;
and Sykora, K.
The
serotonin uptake inhibitor citalopram attenuates ethanol intake.
Clinical Pharmacology and Therapeutics 41:266-274, 1987.
Naranjo,
C.A.; Sullivan, J.T.; Kadlec, K.E.; Woodley-Remus, D.V.;
Kennedy, G.; and Sellers, E.M.
Differential
effects of viqualine on alcohol intake and other consummatory
behaviors. Clinical Pharmacology and Therapeutics 46:301-309,
1989.
Nash, J.M.
Addicted.
Time 149(18):69-76, 1997.
National
Institute on Alcohol Abuse and Alcoholism (NIAAA).
Eighth
Special Report to the U.S. Congress on Alcohol and Health From
the Secretary of Health and Human Services, September 1993. NIH
Pub. No. 94-3699. Bethesda, MD: National Institutes of Health,
1994.
National
Institute on Alcohol Abuse and Alcoholism (NIAAA).
Neuroscience
research and medications development. Alcohol Alert No. 33 (PH
366), July 1996.
O'Brien,
C.P.; Volpicelli, L.A.; and Volpicelli, J.R.
Naltrexone
in the treatment of alcoholism: A clinical review. Alcohol
13(1):35-39, 1996.
O'Connor,
P.G.; Farren, C.K.; Rounsaville, B.J.; and O'Malley, S.S.
A
preliminary investigation of the management of alcohol
dependence with naltrexone by primary care providers. American
Journal of Medicine 103(6):477B482, 1997.
O'Connor,
P.G., and Kosten, T.R.
Rapid
and ultrarapid opioid detoxification techniques. Journal of the
American Medical Association 279(3):229B234, 1998.
O'Malley,
S.S.; Croop, R.S.; Wroblewski, J.M.; Labriola, D.F.; and
Volpicelli, J.R.
Naltrexone
in the treatment of alcohol dependence: A combined analysis of
two trials. Psychiatric Annals 25:681-688, 1995.
O'Malley,
S.S.; Jaffe, A.J.; Chang, G.; Rode, S.; Schottenfeld, R.S.;
Meyer, R.E.; and Rounsaville, B.
Six
month follow-up of naltrexone and psychotherapy for alcohol
dependence. Archives of General Psychiatry 53:217-224, 1996a.
O'Malley,
S.S.; Jaffe, A.J.; Chang, G.; Schottenfeld, R.S.; Meyer, R.E.;
and Rounsaville, B.
Naltrexone
and coping skills therapy for alcohol dependence: A controlled
study. Archives of General Psychiatry 49:881-887, 1992.
O'Malley,
S.S.; Jaffe, A.J.; Rode, S.; and Rounsaville, B.J.
Experience
of a "slip" among alcoholics treated with naltrexone
or placebo. American Journal of Psychiatry 153: 281-283, 1996b.
O'Malley,
S.S.; Krishnan-Sarin, S.; Farren, C.K.; O'Connor, P.G.;
Golubchikov, V.; and Rounsaville, B.J.
Predictors
of naltrexone-induced nausea in alcohol-dependent subjects.
Alcoholism: Clinical and Experimental Research 20:91A, 1996c.
Oslin, D.;
Liberto, J.; O'Brien, C.P.; Krois, S.; and Norbeck, J.
Naltrexone
as an adjunctive treatment for older patients with alcohol
dependence. American Journal of Geriatric Psychiatry 5:324-332,
1997.
Pettinati,
H.M.
Use
of serotonin selective pharmacotherapy in the treatment of
alcohol dependence. Alcoholism: Clinical and Experimental
Research 20(7):23A-29A, 1996.
Physicians
Desk Reference (PDR), 51st ed.
Montvale,
NJ: Medical Economics, 1997.
Pickens,
R.W.; Svikis, D.S.; McGue, M.; Lykken, D.T.; Heston, L.L.; and
Clayton, P.J.
Heterogeneity
in the inheritance of alcoholism. Archives of General Psychiatry
48:19-28, 1991.
Regier,
D.A.; Farmer, M.E.; Rae, D.S.; Locke, B.Z.; Keith, S.I.; Judd,
L.L.; and Goodwin, F.K.
Comorbidity
of mental disorders with alcohol and other drug use: Results
from the epidemiologic catchment area (ECA) study. Journal of
the American Medical Association 264:2511-2518, 1990.
Reid, L.D.;
Delconte, J.D.; Nichols, M.L.; Bailey, E.J.; and Hubbard, C.J.
Tests
of opioid deficiency hypothesis hypotheses of alcoholism.
Alcohol 8:247-257, 1991.
Reid, L.D.;
Gardel, Gardell, L.R.; Chattopadyay, S.; and Hubbell, C.L.
Periodic
naltrexone and propensity to take alcoholic beverage. Alcohol
Clinical and Experimental Research 20:1329-1334, 1996.
Research
Institute on Addictions.
New
drug approved for alcoholism treatment: RIA study plays role in
approval. Research in Brief May 1995.
Restak,
R.R.
The
Mind. New York: Bantam Books, 1988.
Rice, D.P.;
Kelma, S.; Miller, L.S.; and Dunmeyer, S.
The
Economic Costs to Society of Alcohol and Drug Abuse and Mental
Illness: 1985. DHHS Publication No. (ADM) 90-1694. Rockville,
MD: U.S. Department of Health and Human Services, Public Health
Service, Alcohol, Drug Abuse, and Mental Health Administration,
1990.
Salloum,
I.M.; Cornelius, J.R.; Thase, M.E.; Daley, D.C.; Kirisci, L.;
and Spotts, C.
Naltrexone
utility in depressed alcoholics. Psychopharmacology Bulletin
34(1):111-115, 1998.
Sax, D.S.;
Kornetsky, C.; and Kim, A.
Lack
of hepatotoxicity with naltrexone treatment. Journal of Clinical
Pharmacology 34(9):898-901, 1994.
Schurman,
R.A.; Kramer, P.D.; and Mitchell, J.B.
The
hidden mental health network: Treatment of mental illness by
nonpsychiatric physicians. Archives of General Psychiatry
42:89-94, 1985.
Shapiro,
S.; Skinner, E.A.; Kessler, L.G.
Utilization
of health and mental health services: Three epidemiological
catchment area sites. Archives of General Psychiatry 41:971-978,
1984.
Siegel, S.
Alcohol
and opiate dependence: Reevaluation of the Victorian
perspective. In: Cappell, H.D.; Glaser, F.B.; and Israel, Y., et
al., eds. Research Advances in Alcohol and Drug Problems, Volume
9. New York: Plenum Press, 1986. pp. 279-314.
Sinclair,
J.D.
Morphine
suppresses alcohol drinking regardless of prior alcohol access
duration. Pharmacology, Biochemistry and Behavior 2:409-412,
1974.
Substance
Abuse and Mental Health Services Administration (SAMHSA), Office
of Applied Studies.
National
Household Survey on Drug Abuse Advance Report No. 18. Rockville,
MD: Substance Abuse and Mental Health Services Administration,
1996. http://www.health.org/pubs/nhsda/96hhs/rtst1012.htm#E9E12
[Accessed Nov. 6, 1997].
Suzdak,
P.D.; Schwarz, Schwartz, R.D.; Skolnick, P.; and Paul, S.M.
Ethanol
stimulates gamma-aminobutyric acid receptor-mediated chloride
transport in rat brain synaptoneurosomes. Proceedings of the
National Academy of Sciences 83:4071-4075, 1986.
Swift, R.M.
Effect
of naltrexone on human alcohol consumption. Journal of Clinical
Psychiatry 56(suppl. 7):24-29, 1995.
Swift, R.M.;
Whelihan, W.; Kuznetsov, O.; Buongiorno, G.; and Hsuing, H.
Naltrexone-induced
alterations in human ethanol intoxication. American Journal of
Psychiatry 151:1463-1467, 1994.
Thiagarajan,
A.B.; Mefford, I.N.; and Eskay, R.L.
Single-dose
ethanol administration activates the hypothalamic-pituitary
axis: Exploration of the mechanism of action. Neuroendocrinology
50:427-432, 1989.
Ulm, R.R.;
Volpicelli, J.R.; and Volpicelli, L.A.
Opiates
and alcohol self-administration in animals. Journal of Clinical
Psychiatry 56(suppl. 7):5-14, 1995.
Verebey,
K.; De Pace, A.; Jukofsky, D.; Volabka, J.V.; and Mule, S.J.
Quantitative
determination of 2-hydroxy-3-methoxy-6 beta-naltrexol (HMN),
naltrexone, and 6 beta-naltrexol in human plasma, red blood
cells, saliva, and urine by has liquid chromatography. Journal
of Analytical Toxicology 4(1):33-37, 1980.
Verebey,
K.; Volavka, J.; Mule, S.J.; and Resnick, R.B.
Naltrexone:
Disposition, metabolism, and effects after acute and chronic
dosing. Clinical Pharmacology and Therapeutics 20: 315-328,
1976.
Volpicelli,
J.R.
Medical
Treatments for Alcohol Dependence. Speech delivered by satellite
broadcast to Veterans' Affairs hospitals in the United States
and reported by the Treatment Research Center, on November 30,
1995.
Volpicelli,
J.R., and O'Brien, C.P.
Introduction:
Opioid involvement in alcohol dependence. Journal of Clinical
Psychiatry 56(suppl. 7):3-4, 1995.
Volpicelli,
J.R.; Alterman, A.I.; Hayashida, M.; and O'Brien, C.P.
Naltrexone
in the treatment of alcohol dependence. Archives of General
Psychiatry 49:876-880, 1992.
Volpicelli,
J.R.; Clay, K.L.; Watson, N.T.; and O'Brien, C.P.
Naltrexone
in the treatment of alcoholism: Predicting response to
naltrexone. Journal of Clinical Psychiatry 56(suppl. 7):39-44,
1995a.
Volpicelli,
J.R.; Clay, K.L.; Watson, N.T.; and Volpicelli, L.A.
Naltrexone
and the treatment of alcohol dependence. Alcohol Health and
Research World 18:272-278, 1994.
Volpicelli,
J.R.; Rhines, K.C.; Rhines, J.S.; Volpicelli, L.A.; and O'Brien,
C.P.
Naltrexone
and alcohol dependence: Role of subject compliance. Archives of
General Psychiatry 54:737-743, 1997.
Volpicelli,
J.R.; Ulm, R.R.; and Hopson, N.
Alcohol
drinking in rats during and following morphine injections.
Alcohol 8:289-292, 1991.
Volpicelli,
J.R.; Volpicelli, L.A.; and O'Brien, C.P.
Medical
management of alcohol dependence: Clinical use and limitations
of naltrexone treatment. Alcohol and Alcoholism 30:789-798,
1995b.
Wikler,
W.A.
Recent
progress in research on the neurophysical basis of morphine
addiction. American Journal of Psychiatry 105:328-338, 1948.
Wikler,
W.A., and Pescor, F.T.
Classical
conditioning of a morphine abstinence phenomenon, reinforcement
of opioid drinking behavior and "relapse" in morphine
addicted rats. Psychopharmacologia 10:255-284, 1967.
Wilde, M.I.,
and Wagstaff, A.J.
Acamprosate:
A review of its pharmacology and clinical potential in the
management of alcohol dependence after detoxification. Drugs
53(6):1038-1053, 1997.
Wise, R.A.
Neuroleptics
and operant behavior: The anhedonia hypothesis. Behavioral and
Brain Science 5:39-87, 1982.
Zink, R.W.;
Rohrbach, K.; and Froehlich, J.C.
Naltrexone
and fluoxetine act synergistically to decrease alcohol intake.
Alcoholism: Clinical and Experimental Research 21(5):104A, 1997.
In
many health care settings, naltrexone may not be on the
formulary. This appendix provides substance abuse counselors and
treatment providers who are interested in making naltrexone
available for their patients with a greater understanding of the
formulary system.
Getting Naltrexone on the Formulary: Strategies for Substance
Abuse Treatment Providers
In
addition to treatment providers becoming familiar with
therapeutic and cost issues related to the use of naltrexone,
the Consensus Panel recommends that they employ strategies such
as the following:
-
Keep informed of State and local policies. The health
care environment is changing, and practices differ from
State to State and from organization to organization.
Substance abuse treatment providers must not only inform
themselves of existing policies, but must also keep an eye
on the horizon for possible changes and provide input when
there are opportunities to do so.
-
Keep abreast of research. In addition to keeping up with
literature in peer-reviewed journals, substance abuse
treatment providers should explore other sources. This can
be done through networking and informed use of data
available on the Internet. (See Figure
B-2 for a listing of Federal and private Web
sites that may be useful.) Staff of programs affiliated with
an academic health center may wish to explore information
available through the University Hospital Consortium, a
membership organization. It sponsors a Technology Assessment
Group that provides objective evaluations of new drugs and
equipment.
-
Make strategic allies. Treatment providers can forge
alliances with three key groups: pharmacists, physicians,
and fiscal analysts. Each brings special value to the
drug-approval and drug-use processes:
Pharmacists
are medication use experts. As part of the practice of
pharmaceutical care, more and more pharmacists interact daily
with physicians, other health professionals, and patients and
their families in ambulatory, community, and inpatient settings.
Substance abuse treatment providers in need of sound information
can turn to pharmacists for advice about naltrexone. Other
counselors and health care providers who are already well versed
in the use of this drug may take a proactive role in sparking
pharmacist interest in naltrexone. Pharmacists, in turn, can
share their insights with prescribers.
-
Physician support is essential.
-
Fiscal analysts who have the ability to take a systemwide
perspective on drug costs can be strategic partners in
efforts to secure approval of naltrexone. Once informed of
the clinical and financial implications of sobriety, they
can help devise ways of documenting its cost-effectiveness
on large scales.
Conclusion
Regardless
of its importance, getting naltrexone on the formulary, one
Panelist observed, is a "smaller piece of the
problem." Ensuring that naltrexone is appropriately used in
the treatment of alcohol dependence may be even more
challenging. Achieving this goal requires educational efforts
directed at policy makers, prescribers, pharmacists, health
administrators, patients, and the public at large. Use of this
TIP can facilitate that educational effort and improve patient
access to naltrexone for the treatment of alcohol dependence.
Why Isn't Naltrexone More
Widely Used?
Naltrexone
has demonstrated efficacy as an important adjunct to the
treatment of alcohol dependence, and it is available for general
practitioners to prescribe. Yet it has not been widely accepted
or tried. The media promoted naltrexone (ReVia®) intensively
when it was initially approved by the Food and Drug
Administration for use in the treatment of alcoholism, and the
pharmaceutical company that manufactures and distributes
naltrexone used standard, but limited, marketing techniques to
publicize the drug. Yet the field has been slow to adopt the use
of naltrexone.
There may be several reasons for this. First, because the
initial studies were relatively small and ongoing research was
pending, some practitioners have adopted a wait-and-see
approach. The additional costs associated with naltrexone may
also serve to limit its use. Finally, the fact that there is
typically a long lag between an invention or a new research
finding and its adoption and widespread use by individual
practitioners or programs and organizations in the field has
been extensively documented (National Institute of Mental
Health [NIMH], 1971; Backer,
1991). Even though the Federal Government spends
millions of dollars annually to support carefully selected
research and service demonstrations as well as medications
development, many practical, effective, and innovative new
technologies and procedures languish in published articles in
scientific journals without further application. The reasons for
this apparent gap between research and its application have also
been extensively studied with increasing intensity following the
implementation of Great Society programs and the War on Poverty
during the 1960s and 1970s. In fact, knowledge development and
application has become a professional field with its own
scholarly journals, bibliographies, and government-supported or
nonprofit research institutes and university-based programs.
These activities are known under various rubrics as technology
transfer, information dissemination, research utilization,
diffusion of innovation, policy research, and organizational
change efforts (Backer, 1991).
Some of the general tenets of this field that seem applicable to
the planned use of naltrexone as a new tool for the treatment of
alcohol dependence are summarized in the paragraphs that follow.
Investigators have identified a number of reasons why research
findings and innovative technologies are not readily adopted in
the field. Among the most commonly cited causes are the
inadequate strategies used for disseminating new knowledge and
the different perspectives of researchers and practitioners.
Not only does publication of research findings take an excessive
amount of time, but the journals in which articles appear are
seldom read by more than a few interested professionals and not
regularly by those practitioners most likely to benefit from the
results (NIMH,
1971). Moreover, research findings are not usually
packaged in readily understandable language with clearly
specified recommendations that practitioners can replicate in
their own programs. Scholarly articles often contain extensive
details that are of little interest to busy practitioners (Backer, 1991).
Other frequently cited reasons for the failure to apply research
findings or adopt innovations include the threats that change
poses to an organization and its staff, the lack of readily
available resources needed to implement the change, and the
uncertainty about whether the innovation will actually work as
well in another setting or with a different target population
than the one used for the original research (NIMH,
1971; Backer, 1991).
Figure
C-1 lists four critical challenges to the effective
use of research findings identified by one investigator in this
area.
Strategies That Encourage
Technology Transfer and Research Utilization
Researchers
have noted that certain characteristics of both the innovation
and the organizations and professionals that are considering its
adoption affect the probability that a new, but tested,
methodology or procedure will be successfully incorporated into
routine practice (NIMH, 1971).
Some of these characteristics are summarized in Figure
C-2.
Strategies Specific to
Naltrexone Pharmacotherapy
Although
patients and family members may be stimulated by media publicity
about naltrexone to ask questions of their treatment providers
or physicians, they do not have the necessary influence and
authority to actually get a prescription if their inquiries are
met with indifference or overt rejection. Because incorporation
of naltrexone into the alcohol dependence treatment spectrum is
not an automatic response--even though the medication's safety
and efficacy have been demonstrated--programs that want to adopt
its use may need a planned strategy. The following steps should
be considered in applying the research findings on the use of
naltrexone. The steps may be conducted in any order or
simultaneously:
-
Disseminate information about naltrexone to all levels of
the health care organization, including treatment providers,
ancillary staff, and patients who need to become aware of
the drug, its demonstrated efficacy in the treatment of
alcohol dependence, and its safety. Start by conveying basic
information. Information can be presented in printed
materials but is more likely to be assimilated if delivered
through in-service training, media presentations, or
conferences. Make certain that information is translated
into language the audience understands and that the content
is targeted to the audience's needs.
-
Identify advocates and build alliances among them to
ensure a climate of acceptance and support for use of the
medication. Advocates can also be used as potential
consultants or facilitators of the change process. Potential
resources include the following:
-
State
substance abuse authority
-
American
Council on Alcoholism
-
State
psychological associations
-
National
Alliance for the Mentally Ill (NAMI)
-
Washington
Alliance for the Mentally Ill (WAMI)
-
Researchers
who have investigated naltrexone
-
State
medical society members
-
American
Society of Addiction Medicine (ASAM) members
-
National
Association of Alcohol and Drug Abuse Counselors
-
Staff
and directors of existing treatment programs that show
success in using naltrexone
-
Representatives
from Employee Assistance Programs (EAPs), criminal justice
system offices of probation and parole, or other health
care providers who have witnessed positive responses to
naltrexone as an adjunct to the treatment of alcohol
dependence
-
Consumers
and family members who can move prescribers to try the
drug
-
Enlist the support of influential administrators and
organizational leaders whose endorsement will be necessary
for incorporating naltrexone into the treatment protocol.
The probability that this medication will be used
appropriately is increased dramatically if leaders express
enthusiasm for its adoption or actively assist with its
introduction (e.g., by issuing directives, by making funding
and other necessary resources available).
-
Determine which perceived needs and problems of the
organization and consumers could be alleviated by the
introduction of naltrexone. Motivation to introduce change
is enhanced by heightened sensitivity to specific problems
such as high rates of relapse or early treatment termination
among alcohol-dependent patients in the treatment program or
among specific subsets of this population (e.g., patients
with dual disorders). Pressure for change can come from
patients and families who experience repeated treatment
failures with the current protocols or from staff members
who are dissatisfied with patients' progress.
-
Arrange personal contacts between staff members of the
organization that is considering naltrexone and persons who
have first-hand knowledge of its safety and utility, which
might include the form of consultation provided by outside
experts.
-
Acquire direct experience with naltrexone by setting up a
small pilot demonstration or an open-label trial for
approximately 20 to 50 appropriately selected patients to
see how they respond compared with baseline functioning
after 3 to 6 months on naltrexone as an adjunct to standard
treatment. This is ultimately the most convincing evidence
that the medication is appropriate for the population of
patients served by the provider or program. It is also a
useful way to discover resistance to the use of naltrexone
or other unanticipated administrative problems. If
naltrexone is not already on the formulary or covered by
patients' insurance, the pharmaceutical company that
distributes naltrexone is often willing to make the drug
available for a limited period of time for indigent patients
who cannot afford to pay for it. Because many physicians are
only comfortable prescribing drugs with which they have
become familiar and are reluctant to try new ones without
backup, a pilot demonstration that includes an experienced
medical consultant and necessary laboratory resources may be
a useful mechanism for introducing the drug into practice.
-
Recognize and overcome resistance that can undermine
innovation. In the case of naltrexone, resistance is likely
to come from several sources: (1) opposition to any type of
pharmacotherapeutic support as part of "drug-free"
treatment, (2) the incremental costs added to an already
overburdened treatment system by the expenses incurred in
prescribing naltrexone and providing for laboratory
monitoring of liver functioning, (3) difficulties in
coordinating medical services with appropriate psychosocial
supports in systems that have not relied heavily on
physician involvement, (4) threats to the job security of
nonmedically trained counselors, and (5) lack of a basic
understanding of the brain mechanisms of addiction.
Some
staff members and patients in alcohol treatment programs with an
Alcoholics Anonymous (AA)-type orientation and philosophy may
resist the introduction of any type of pharmacotherapy because
they view this as a "crutch" substituted for personal
responsibility and the support of peers in self-help groups.
Staff members may also believe that immediate discharge is
necessary if abstinence is not maintained from the point of
treatment entry. However, naltrexone may help prevent relapse
among those who slip. Some AA and Narcotics Anonymous (NA)
groups and outpatient "drug-free" treatment programs
have come to accept concurrent pharmacotherapy for depression or
other mental disorders and even methadone-maintained patients.
Educating staff and patients in these treatment systems about
the biochemical changes in the brain that alcohol and other drug
dependence cause may be useful. It should be emphasized that
such changes are treatable and often reversible with
pharmacotherapeutic agents that help reestablish normality of
brain functions and behaviors so that rehabilitation can take
place through counseling and other therapeutic services (National
Institute on Drug Abuse, 1996). Naltrexone may be
more readily accepted by mental health systems and their
patients or opioid treatment programs that already rely on
pharmacotherapy as an appropriate treatment adjunct.
Another point of resistance may be the incremental costs added
per patient to the treatment of alcohol dependence. In such
situations, the arguments of experts will need to be carefully
tailored to the realities that programs face. Unfortunately,
studies on the cost-effectiveness of naltrexone have not yet
been completed. As a result, potential cost offsets can only be
suggested.
Some persuasive points may be that naltrexone is becoming an
appropriate standard of care for refractory alcohol-dependent
patients and that naltrexone is not very costly compared with
other drugs prescribed for chronic medical illnesses. The use of
naltrexone may lead to cost savings elsewhere in the health care
system (e.g., hospital care, detoxification services, domestic
violence reduction). For example, if serious relapse is
prevented, then there may be reductions in the use of hospital
care detoxification services or prevention/reduction of medical
illnesses. The largest cost savings may be among high and
chronic users of the physical health and mental health systems
(e.g., patients with serious medical illnesses that are
exacerbated by drinking, patients with dual disorders), although
no data have yet been compiled to confirm this effect.
Ethnicity and culture may play important roles in the
acceptability of naltrexone by patients as well as by health
care system representatives. Language issues are always
important, as are different cultural attitudes toward the use of
medications and psychosocial therapies. Cultural sensitivity is
essential in establishing an appropriate treatment program
environment.
Problems may also be posed and resistance encountered because
naltrexone requires coordination of medical and psychosocial
approaches that are not always well integrated in current
substance abuse treatment modalities. These difficulties are
best addressed by careful, but flexible, planning. The case
studies that are presented in this appendix offer examples of
how naltrexone can be effectively incorporated into a community
mental health center program and into a State-certified
substance abuse treatment program.
Preparing the System for
Using Naltrexone as a Treatment Adjunct
A
carefully developed plan for adopting an innovation to a new
setting is essential for its success. All staff members who will
be involved in using naltrexone should be included in planning
for its introduction so that their needs are considered and they
develop some "ownership" of the process, thereby
decreasing resistance to the change (Backer,
1991). The following steps should be completed before
naltrexone is introduced:
-
Identify the prescriber before introducing naltrexone.
The system or program should make certain this person is
fully educated about the appropriate use of this
pharmacotherapy and is convinced that naltrexone can be an
effective adjunct to the treatment of alcohol dependence for
well-selected patients.
-
Educate all members of the system/program about
naltrexone at the level of knowledge necessary for their
assigned roles. Some resources are available from the
pharmaceutical company for this purpose. DuPont Merck has
publications directed to physicians, counselors, and
patients.
-
Educate and/or train treatment program admissions
coordinators about naltrexone and have coordinators identify
naltrexone candidates at the time of intake.
-
Make certain that naltrexone is available on the Medicaid
formulary or through insurance reimbursement and special
programs for indigent patients (see
Appendix B).
-
Ensure coordination with appropriate psychosocial
components that are already available as standard care or
that are specially developed or enhanced. As part of a
comprehensive treatment program, refer to 12-Step programs
such as AA, NA, or other groups that are known to accept
patients who are using prescribed drugs.
-
Develop and disseminate a formal protocol that includes
criteria and procedures for screening and admitting
patients; conducting the initial and followup physical
evaluations; referring patients for additional medical
services and psychosocial therapy; discharging, extending,
and terminating patients from naltrexone treatment and the
addictions program; handling any emergencies that may occur;
and evaluating the effectiveness of the program.
Case Study 1: Starting a
Naltrexone Treatment Program in a Community Mental Health Center
An
urban community mental health center (CMHC) in Illinois
successfully integrated naltrexone treatment into available
services for indigent patients with dual disorders. The CMHC
instituted a flexible approach to coordinated care and enlisted
the vital support of its medical director. Although an
addictions treatment program was associated with the CMHC, its
staffing, administration, and protocols were different and
separate from the psychological and psychiatric services.
Moreover, it was the policy of the addictions treatment
component to discharge any patient immediately who relapsed into
drinking (or drug using) and to terminate all contact with the
CMHC, even if the patient was receiving pharmacotherapy for a
mental disorder. This problem was addressed by simultaneously
enrolling patients with dual disorders into both the addictions
treatment and the medical services components so they could
continue to have physician appointments after compulsory
discharge from the addictions treatment program.
Because the CMHC administered different services (such as
psychotherapy, group therapy, case management) under different
programs, coordination of care was administratively complex. A
nurse from the CMHC's medical services program was assigned
responsibility for coordinating care for all patients who were
taking naltrexone regardless of program. In addition to
physician visits for prescription of naltrexone, patients
continued their participation in whatever psychosocial
treatments were appropriate for their particular psychiatric
illness. Patients were not required to participate in
traditional addictions treatment, primarily because most of the
patients were unwilling or inappropriate for such programs. In
practice, this individualized psychosocial treatment was more
effective than previously fixed programmatic requirements,
especially for patients who were unable to achieve abstinence
immediately. Patients could also receive naltrexone at no cost
through the pharmaceutical company's special program for
indigent patients.
The coordinated and individualized approach exposed many staff
members in a variety of service components to patients who were
taking and responding to naltrexone. The improvements in
patients taking naltrexone quickly stimulated the interest of
these treatment providers and generated patient referrals. These
patients were being followed in psychological support programs
but had either refused or failed treatment in the addictions
program. Individualized psychosocial care for patients with dual
disorders who were taking naltrexone was particularly effective.
The clinical records of 72 patients with dual disorders who were
treated with naltrexone were reviewed. Diagnoses included
-
Major depression (n = 37)
-
Schizophrenia (n = 17)
-
Bipolar illness (n = 11)
-
Schizoaffective disorder (n = 7)
-
Transsexualism (n = 4)
Concurrent
psychotropic medications included antidepressants, neuroleptics,
lithium, divalproex, benzodiazepines, disulfiram, atypical
antipsychotics, and estrogens.
Although common adverse effects (mostly nausea) during the first
2 weeks were noted in 26 percent of the patients who began
taking naltrexone, only 11 percent found the effects severe
enough to discontinue the medication. The response to naltrexone
among these patients with coexisting disorders was impressive,
with 59 patients (82 percent) achieving at least a 75-percent
reduction in alcohol intake and only 2 patients (2.8 percent)
having less than a 25-percent reduction in their alcohol
consumption.
This CMHC concluded that the following factors were most helpful
in the successful introduction of naltrexone treatment into the
organization:
-
Administrative support at the top level, in this case by
the CMHC's medical director
-
Coordination by a single person or service given the time
and authority to schedule patients across services for
needed psychosocial and medical care
-
Flexibility in arranging services so that psychosocial
components were individualized for the different and
changing needs of the patients
-
Allowing patients treated with naltrexone to continue in
various psychosocial interventions with assorted agency
staff so that patients' actual positive responses to
naltrexone and their success in avoiding relapse were more
persuasive and convincing than words or in-service training.
In fact, formal education about naltrexone was most
effective after staff members had already been convinced of
the drug's efficacy by contact with successful patients.
Case Study 2: Use of
Naltrexone as a Treatment Supplement for Patients In Publicly
Funded Treatment Programs
The
Washington State agency for alcohol and substance abuse used a
small and informal pilot project to demonstrate the
effectiveness of naltrexone as a supplemental adjunct in the
standard treatment of alcohol dependence. The results of the
pilot project, together with the already available research
literature, were sufficiently convincing for the State Medical
Assistance Administration to add naltrexone to the State's
formulary for qualified patients in publicly supported alcohol-
and opioid-dependence treatment programs. These patients must be
enrolled in State-certified substance abuse treatment programs
that have been authorized to use naltrexone. The patients must
get the prescription from a physician and must have a current
medical identification card that is not restricted to emergency
care, family planning services, or other specified limitations.
A protocol and forms were designed so that counselors in the
substance abuse treatment programs could recommend naltrexone,
obtain consent from patients to add the medication to the
treatment plan, and issue naltrexone authorization cards that
would allow patients to receive (and pharmacies to be reimbursed
for) naltrexone capsules for a 3-month period (12 weeks). The
protocol included three prescriptions of a 34-day supply,
provided that no more than two unauthorized breaks in treatment
would occur. The authorization cards required patient consent
for disclosure of confidential information for 90 days to the
patient's private physician and a designated pharmacy.
Counselors were also instructed to confer with and regularly
record the reactions and treatment progress of patients who
agreed to use naltrexone. It was also recommended that issues
pertaining to naltrexone use be discussed in individual
counseling sessions rather than in groups where any reports of
early common adverse effects might deter other patients from
considering the use of naltrexone. Counselors were encouraged to
incorporate naltrexone into the treatment regimen; to inform
themselves about its efficacy; to educate patients about the
medication, using materials available from the pharmaceutical
company that supplies naltrexone; and most important, to
"pass this information on to all physicians [they] may have
contact with."
During 1995, the pilot project enrolled a total of 50 patients
with alcohol dependence from two outpatient substance abuse
treatment programs in Seattle, Washington, with the following
results:
-
42 percent (n = 21) completed 90 days of treatment while
taking naltrexone.
-
10 percent (n = 5) relapsed to drinking and stopped
taking naltrexone.
-
15 percent (n = 7) stopped taking naltrexone due to
reported common adverse effects, including nausea; feeling
wired, jittery, or restless; hot flashes; weight loss or a
decrease in appetite; or headache. Most common adverse
effects dissipated after 2 weeks, and physicians at the
participating facilities split doses or decreased them to
reduce patient-reported symptoms.
-
15 percent (n = 7) quit taking naltrexone because they
felt they did not need it and believed they could stay sober
on their own, using learned skills and other supports.
-
50 percent (n = 25) reported no alcohol consumption while
taking naltrexone.
-
72 percent (n = 36) reported a decrease in the craving
for alcohol while taking naltrexone.
-
72 percent of the patients who did resume drinking (n =
18 of 25) while taking naltrexone consumed less alcohol than
they usually did before starting the medication.
-
Women appeared to respond more readily to naltrexone than
did men, and the women showed better outcomes from use of
naltrexone.
-
Patients experienced some difficulty in making an initial
connection with the prescribing physician.
-
Patients required close monitoring for the first 2 weeks
that they took naltrexone. The recommended practice during
this time was to discuss medication issues in individual
counseling sessions, not in group therapy.
-
Naltrexone also appeared to have a positive effect on
concurrent use of other drugs in addition to alcohol, as
evidenced by a decrease in the number of positive urinalysis
results for other drugs.
References
Backer,
T.E.
Drug
Abuse Technology Transfer: Clinical Report Series. National
Institute on Drug Abuse. DHHS Pub. No. (ADM) 91-1764. Rockville,
MD: Department of Health and Human Services, 1991.
National
Institute on Drug Abuse.
Drug
Abuse and Drug Abuse Research: The Fifth Triennial Report to
Congress From the Secretary, Department of Health and Human
Services. Washington, DC: Department of Health and Human
Services, November 1996 (limited distribution publication).
National
Institute on Mental Health (NIMH).
Planning
for Creative Change in Mental Health Services: A Distillation of
Principles on Research Utilization--Volume I. DHEW Publication
No. (HSM) 73-9148. Washington, DC: Department of Health,
Education, and Welfare, 1971.
This
appendix includes
-
Alcohol Urge Questionnaire
-
Obsessive Compulsive Drinking Scale
Alcohol Urge Questionnaire
Listed
below are questions that ask about your feelings about drinking.
The words "drinking" and "have a drink"
refer to having a drink containing alcohol, such as beer, wine,
or liquor. Please indicate how much you agree or disagree with
each of the following statements by placing a single mark (like
this: X ) along each line between STRONGLY DISAGREE and STRONGLY
AGREE. The closer you place your mark to one end or the other
indicates the strength of your disagreement or agreement. Please
complete every item. We are interested in how you are thinking
or feeling right now as you are filling out the questionnaire.
|
RIGHT
NOW
|
-
All
I want to do now is have a drink.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
I
do not need to have a drink now.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
It
would be difficult to turn down a drink this minute.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
Having
a drink now would make things seem just perfect.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
I
want a drink so bad I can almost taste it.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
Nothing
would be better than having a drink right now.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
If
I had the chance to have a drink, I don't think I
would drink it.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
-
I
crave a drink right now.
STRONGLY
DISAGREE:______:______:______:______:______:______:______:STRONGLY
AGREE
Reprinted
with permission from Michael J. Bohn.
|
Obsessive Compulsive
Drinking Scale
Directions:
The questions below ask you about your drinking alcohol and your
attempts to control your drinking. Please circle the number next
to the statement that best applies to you.
-
How much of your time when you're not drinking is
occupied by ideas, thoughts, impulses, or images related to
drinking?
-
)None
-
)Less
than 1 hour a day
-
)1-3
hours a day
-
)4-8
hours a day
-
)Greater
than 8 hours a day
-
How frequently do these thoughts occur?
-
)Never
-
)
No more than 8 times a day
-
)More
than 8 times a day, but most hours of the day are free of
those thoughts
-
)More
than 8 times a day and during most hours of the day
-
)Thoughts
are too numerous to count, and an hour rarely passes
without several such thoughts occurring.
Insert
the Higher Score of Questions 1 or 2 here_____
-
How much do these ideas, thoughts, impulses, or images
related to drinking interfere with your social or work (or
role) functioning? Is there anything you don't or can't do
because of them? [If you are not currently working, how much
of your performance would be affected if you were working?]
-
)Thoughts
of drinking never interfere--I can function normally.
-
)Thoughts
of drinking slightly interfere with my social or
occupational activities, but my overall performance is not
impaired.
-
)Thoughts
of drinking definitely interfere with my social or
occupational performance, but I can still manage.
-
)Thoughts
of drinking cause substantial impairment in my social or
occupational performance.
-
)Thoughts
of drinking interfere completely with my social or work
performance.
-
How much distress or disturbance do these ideas,
thoughts, impulses, or images related to drinking cause you
when you're not drinking?
-
)None
-
)Mild,
infrequent, and not too disturbing
-
)Moderate,
frequent, and disturbing, but still manageable
-
)Severe,
very frequent, and very disturbing
-
)Extreme,
nearly constant, and disabling distress
-
How much of an effort do you make to resist these
thoughts or try to disregard or turn your attention away
from these thoughts as they enter your mind when you're not
drinking? (Rate your efforts made to resist these thoughts,
not your success or failure in actually controlling them.)
-
)My
thoughts are so minimal, I don't need to actively resist.
If I have thoughts, I make an effort to always resist.
-
)I
try to resist most of the time.
-
)I
make some effort to resist.
-
)I
give in to all such thoughts without attempting to control
them, but I do so with some reluctance.
-
)I
completely and willingly give in to all such thoughts.
-
How successful are you in stopping or diverting these
thoughts when you're not drinking?
-
)I
am completely successful in stopping or diverting such
thoughts.
-
)I
am usually able to stop or divert such thoughts with some
effort and concentration.
-
)I
am sometimes able to stop or divert such thoughts.
-
)I
am rarely successful in stopping such thoughts and can
only divert such thoughts with difficulty.
-
)I
am rarely able to divert such thoughts even momentarily.
-
How many drinks do you drink each day?
-
)None
-
)Less
than 1 drink per day
-
)1-2
drinks per day
-
)3-7
drinks per day
-
)8
or more drinks per day
-
How many days each week do you drink?
-
)None
-
)No
more than 1 day per week
-
)2-3
days per week
-
)4-5
days per week
-
)6-7
days per week
Insert
the Higher Score of Questions 7 or 8 here____
-
How much does your drinking interfere with your work
functioning? Is there anything that you don't or can't do
because of your drinking? [If you are not currently working,
how much of your performance would be affected if you were
working?]
-
)Drinking
never interferes--I can function normally.
-
)Drinking
slightly interferes with my occupational activities, but
my overall performance is not impaired.
-
)Drinking
definitely interferes with my occupational performance,
but I can still manage.
-
)Drinking
causes substantial impairment in my occupational
performance.
-
)Drinking
problems interfere completely with my work performance.
-
How much does your drinking interfere with your social
functioning? Is there anything that you don't or can't do
because of your drinking?
-
)
Drinking never interferes--I can function normally.
-
)Drinking
slightly interferes with my social activities, but my
overall performance is not impaired.
-
)Drinking
definitely interferes with my social performance, but I
can still manage.
-
)Drinking
causes substantial impairment in my social performance.
-
)Drinking
problems interfere completely with my social performance.
Insert
the Higher Score of Questions 9 or 10 here____
-
If you were prevented from drinking alcohol when you
desired a drink, how anxious or upset would you become?
-
)I
would not experience any anxiety or irritation.
-
)I
would become only slightly anxious or irritated.
-
)The
anxiety or irritation would mount, but remain manageable.
-
)I
would experience a prominent and very disturbing increase
in anxiety or irritation.
-
)I
would experience incapacitating anxiety or irritation.
-
How much of an effort do you make to resist consumption
of alcoholic beverages? (Only rate your effort to resist,
not your success or failure in actually controlling the
drinking.)
-
)My
drinking is so minimal, I don't need to actively resist.
If I drink, I make an effort to always resist.
-
)I
try to resist most of the time.
-
)I
make some effort to resist.
-
)I
give in to almost all drinking without attempting to
control it, but I do so with some reluctance.
-
)I
completely and willingly give in to all drinking.
-
How strong is the drive to consume alcoholic beverages?
-
)No
drive
-
)Some
pressure to drink
-
)Strong
pressure to drink
-
)Very
strong drive to drink
-
)The
drive to drink is completely involuntary and overpowering.
-
How much control do you have over the drinking?
-
)I
have complete control.
-
)I
am usually able to exercise voluntary control over it.
-
)I
can control it only with difficulty.
-
)I
must drink and can only delay drinking with difficulty.
-
)I
am rarely able to delay drinking even momentarily.
Insert
the Higher Score of Questions 13 or 14 here____
Figure 2-1: Information on
Naltrexone for the Primary Health Care Provider
|
Figure
2-1
Information on Naltrexone for the Primary Health Care
Provider
|
-
Naltrexone
is an appropriate treatment for alcohol-dependent
patients, including binge drinkers.
-
The
only absolute medical contraindications are liver
failure, acute infectious hepatitis, and current
dependence on opioids or active opioid withdrawal.
Elevated bilirubin levels, pregnancy, breast feeding,
and use in adolescents are relative contraindications.
-
At
the currently recommended dose of 50 mg daily, hepatic
toxicity is very unlikely. Continued alcohol use is
more likely than naltrexone to cause liver damage.
-
Providers
should perform LFTs prior to treatment initiation and
periodically during treatment.
-
Abstinence
should be a desired goal for the patient; however,
reductions in drinking may be an acceptable
intermediate outcome. Failure to maintain complete
abstinence is not necessarily a failure of treatment
because there are many other areas of a patient's life
that can improve, such as job performance, social
relationships, and general physical health. This is
similar to the goal of reducing high blood pressure;
not all patients will have a total improvement of
hypertension.
-
Naltrexone
is likely to be most effective when used in
combination with other forms of treatment for
alcoholism, such as psychosocial interventions, and
when the patient complies with both.
|
Figure 2-2: Absolute and
Relative Contraindications for Naltrexone
|
Figure
2-2
Absolute and Relative Contraindications for Naltrexone
|
|
Absolute
|
Relative
|
-
Acute
hepatitis
-
Liver
failure
-
Chronic
opioid dependence or current opioid use, especially
methadone or LAAMa
-
Active
opioid withdrawal (Note: The naltrexone-clonidine
combination can be used in opioid withdrawal
procedures.)
|
-
Significant
hepatic dysfunction
-
Anticipated
need for opioids to treat an identified medical
problemb
-
Pregnancyc
-
Breast
feedingc
-
Use
in adolescentsc
|
|
aThis
includes not only illegal opiates such as morphine or
heroin, but also opioid-containing medications that are
prescribed for managing pain and treating serious medical
conditions such as heart disease, severe arthritis, sickle
cell anemia, and recurrent congestive heart failure.
bFor individuals who are taking naltrexone, prescription
or over-the-counter analgesics, cough medicines, and pain
medications that contain opioids--such as oxycodone
hydrochloride (e.g., Percodan), hydrocodone bitartrate
(e.g., Vicodin), and codeine (e.g., Robitussin A-C)--may
not be effective. Naltrexone does not affect nonsteroidal
anti-inflammatory drugs (e.g., Advil, Aleve), aspirin, or
acetaminophen (e.g., Tylenol). Naltrexone blocks the
effect of loperamide hydrochloride (Imodium) against
diarrhea. Bismuth compounds (Pepto-Bismol) may be used for
mild nausea or diarrhea, and octreotide acetate (Sandostatin)
may be used for severe diarrhea, and ondansetron
hydrochloride (Zofran) may be used for nausea and
vomiting, especially with accidental
naltrexone-precipitated opiate withdrawal.
cUntil further research is done, due to the effects of
naltrexone on hormonal status, especially growth hormone,
luteinizing hormone, and prolactin.
|
Figure 2-3: Elements of
Pretreatment Workup
|
Figure
2-3
Elements of Pretreatment Workup
|
-
Physical
examination of the liver and thorough laboratory
screening of liver function
-
Laboratory
tests including
-
Serum
aminotransferases
-
Total
bilirubin
-
Pregnancy
test (urine or blood)
-
Urine
toxicology screen
-
Complete/updated
medical history
-
Substance
use/abuse history combined with a screening for signs
and symptoms of recent narcotic use
-
Mental
health/psychiatric status screening with a focus on
anxiety, depression, psychosis, and level of cognitive
functioning
|
|
Figure 2-4: Dosing
Strategies for Starting Naltrexone Treatment a
|
Figure
2-4
Dosing Strategies for Starting Naltrexone Treatmenta
|
|
General
Approach
|
Specialized
Approach
|
-
For
most patients
-
50
mg/day
|
-
For
patients judged likely to be at risk for adverse
effects, such as younger patients and those with
shorter durations of abstinence.
-
12.5
mg/day or 25 mg/day for a few days, then gradually
increase to 50 mg daily. This dose can be divided into
two doses, each with a meal if desired.
|
|
Note:
If severe common adverse effects occur after the initial
dose, stop the medicine, then resume at a lower dose 1 or
2 days after the symptoms have subsided.
|
|
a
Treatment with naltrexone should be tailored to patient
needs. Dosing strategies described are examples of models
used by some programs; they do not represent definitive
guidelines.
|
Figure 2-5: Safety
Identification Card
|
Figure
2-5
Safety Identification Card
|
|
Side 1
TO
MEDICAL PERSONNEL TREATING ME IN AN EMERGENCY:
This
patient is taking the oral opioid antagonist reVia®,
formerly known as Trexan® (naltrexone hydrochloride).
In an emergency situation in patients receiving fully
blocking doses of reVia®,a suggested plan of management
is regional anesthesia, conscious sedation with a
benzodiapine, use of non-opioid analgesics, or general
anesthesia.
In a situation requiring opioid analgesia, the amount of
opioid required may be greater than usual, and the
resulting respiratory depression may be deeper and more
prolonged.
A rapidly acting opioid analgesic that minimizes the
curation of respiratory depression is preferred. The
amount of analgesia administered should be titrated to the
needs of the patient. Non-receptor mediated actions may
occur and should be expected (e.g., facial swelling,
itching, generalized erythemia, or bronchoconstriction),
presumably due to histamine release.
Irrespective of the drug chosen to reverse reVia ®
(naltrexone hydrochloride) blockade, the patient should be
monitored closely by appropriately trained personnel in a
setting equipped and staffed for cardiopulmonary
resuscitation.
For
medical emergencies, call your regional Poison Control
Center.
Further
information may be obtained by calling: 1-800-4PHARMA.
|
|
Side 2
The
name and telephone number of physician who prescribed
reVia® (naltrexone hydrochloride).
Physician's name:
___________________________________________________________________
Physician's telephone:
_______________________________________________________________
Patient's name:
_____________________________________________________________________
Patient's telephone:
_________________________________________________________________
Date treatment was initiated:
_________________________________________________________
|
Figure 3-3: Opiates Versus
Opioids
|
Figure
3-3
Opiates Versus Opioids
|
-
Opiates
such as morphine and heroin are derived from opium,
which is harvested from the opium poppy (Papaver
somiferum). Through their research on opiate
addiction, scientists discovered specific sites in the
central nervous system where opiates attach and exert
their effect. These sites are called opioid receptors.
Subsequent to this discovery, scientists were able to
identify the naturally occurring chemicals produced by
the body that also attach to opioid receptors.
-
In
this document, the term opiate refers to drugs like
morphine and heroin, whereas the term opioid refers to
naturally occurring chemicals such as enkephalins and
endorphins (endogenous opioids) that exert opiate-like
effects by interacting with central nervous system
opioid receptors.
|
Figure 4-1: Outcomes for
Naltrexone- and Placebo-Treated Subjects
|
Figure
4-1
Outcomes for Naltrexone- and Placebo-Treated Subjects
|
|
Outcome
|
Naltrexone
(n = 35)
|
Placebo
(n = 35)
|
|
Completion
rate
|
69%
|
60%
|
|
Sampled
alcohol
|
46%
|
57%
|
|
Drinking
days
|
1.6%
|
8.3%
|
|
Total
relapsing
|
23%
|
54%
|
|
Relapse
among those who "slipped"
|
50%
|
95%
|
|
Mean
craving score at termination (0-9)
|
1.41
|
3.42
|
|
Source:
Volpicelli et al., 1992.
|
Figure B-2: Federal and
Private Web Sites
|
Figure
B-2
Federal and Private Web Sites
|
|
Substance
Abuse and Mental Health Services Administration (SAMHSA)
Sites
|
|
Other
Federal Sites
Private
Sites
|
Figure C-1: Critical
Challenges to Effective Use of Research Findings
|
Figure
C-1
Critical Challenges to Effective Use of Research Findings
|
-
Lack
of awareness--potential users do not know about the
innovation.
-
Lack
of conviction--potential users are not certain that
the innovation will work in their setting without
unreasonable costs or adverse effects.
-
Lack
of resources--potential users may not have access to
needed funding, materials, or trained personnel for
adopting the innovation.
-
Lack
of preparation for change--which can be threatening to
staff and difficult to implement, particularly in
large and complex organizations.
Source:
Adapted from Backer, 1991.
|
Figure C-2: Characteristics
of an Organization That Is Likely to Adopt an Innovation
|
Figure
C-2
Characteristics of an Organization That Is Likely to Adopt
an Innovation
|
-
Organizational
climate that supports the concept of change,
creativity, and innovation through open communication
among personnel, with all levels participating in the
making of decisions; collegial endorsement of
help-seeking and problem-solving; available time for
consideration of innovation
-
Organizational
size and structure with some emphasis on
self-monitoring and assessment to detect troubles,
without being too big or too complex for rapid
assimilation of change or too bureaucratic,
complacent, or conforming to tradition
-
Organizational
affluence and capacity that is sufficient to risk
innovation and provide the resources for implementing
change
-
Leaders
in the organization who are attuned to change,
politically astute, and respectful of different
professional disciplines
-
Professionalism,
age, and security of staff members who look forward to
innovations; are not threatened by change; and are
willing to entertain, discuss, and attempt new
procedures or technologies
-
Relationship
to the community and the consumer constituency with a
demonstrated ability to lead and a capacity for
autonomy rather than vulnerability and immediate
capitulation to outmoded traditions
Source:
Adapted from National Institute of Mental Health, 1971.
[END]
|
|