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IN REVERSE CHRONOLOGICAL ORDER (emphasis mine):
Brewer C; Wong VS
Naltrexone: report of lack of hepatotoxicity in acute viral hepatitis, with a
review of the literature
Addict Biol; 9(1):81-87; 2004
Many clinicians appear to be concerned about the
potential hepatotoxicity of the opiate antagonist naltrexone (NTX) and this may
be one reason why it is not used more widely in treating both heroin and alcohol
abusers. Some much-quoted early studies noted abnormalities in liver function
tests (LFTs) in very obese patients taking high doses, although there was no
evidence of clinically significant liver dysfunction. These concerns may be
reinforced by advice in the UK product information sheet to perform LFTs before
and during treatment, by high infection rates with hepatitis C virus (HCV) among
injecting heroin addicts and by the frequency of abnormal LFTs in alcohol
abusers. We describe a heroin abuser in whom clinical and laboratory
manifestations of acute hepatitis B and C appeared a few days after the
insertion of a subcutaneous naltrexone implant. A decision was made not to
remove the implant but the hepatitis resolved completely and uneventfully well
within the normal time-scale. A review of the literature indicates that even
when given at much higher doses than are needed for treating heroin or alcohol
abusers, there is no evidence that NTX causes clinically significant liver
disease or exacerbates, even at high doses, serious pre-existing liver disease.
During the past decade, NTX has been shown to be safe and effective in the
treatment of pruritus associated with severe jaundice caused by severe and
sometimes life-threatening cirrhosis and other liver diseases. Its safety, even
in these extreme conditions, is particularly reassuring. We suggest that it may
be more appropriate and economical to advise patients to report promptly any
suspected side effects than to perform regular LFTs, which may be misleading
Lieber CS
Hepatic, metabolic, and nutritional disorders of alcoholism: from
pathogenesis to therapy
Crit Rev Clin Lab Sci; 37(6); 551-584; 2000
Much progress has been made in the understanding of the
pathogenesis of alcoholic liver disease, resulting in an improvement
in treatment. Nutritional deficiencies should be corrected when
present but, because of the alcohol-induced disease process, some of
the nutritional requirements change. For instance, methionine, one of
the essential amino acids for humans, must be activated to S-adenosylmethionine
(SAMe), but, in severe liver disease, the activity of the
corresponding enzyme is depressed. Therefore, the resulting
deficiencies and associated pathology can be attenuated by the
administration of SAMe, but not by methionine. Similarly,
phosphatidylethanolamine methyltransferase (PEMT) activity, which is
important for hepatic phosphatidylcholine (PC) synthesis, is also
depressed in alcoholic liver disease, therefore calling for the
administration of the products of the reaction. Inasmuch as free
radical generation by the ethanol- induced CYP2E1 plays a key role in
the oxidative stress, inhibitors of this enzyme have great promise and PPC, which is presently being evaluated clinically, is particularly
interesting because of its innocuity. In view of the striking negative
interaction between alcoholic liver injury and hepatitis C, an
antiviral agent is eagerly awaited that, unlike Interferon, is not
contraindicated in the alcoholic. Antiinflamatory agents may also be
useful. In addition to steroids, down-regulators of cytokines and
endotoxin are being considered. Finally, anticraving agents such as
naltrexone or acamprosate should be incorporated into any contemplated
therapeutic cocktail
Walsh K; Alexander G
Alcoholic liver disease
Postgrad Med J;76(895); 280-286; 2000
Alcohol is a major cause of liver cirrhosis in the Western world
and accounts for the majority of cases of liver cirrhosis seen in
district general hospitals in the UK. The three most widely recognized
forms of alcoholic liver disease are alcoholic fatty liver (steatosis),
acute alcoholic hepatitis, and alcoholic cirrhosis. The exact
pathogenesis of alcoholic liver injury is still not clear but immune
mediated and free radical hepatic injury are thought to be important.
There is increasing interest in genetic factors predisposing to
hepatic injury in susceptible individuals. Diagnosis is based on
accurate history, raised serum markers such as gamma-glutamyltransferase,
mean corpuscular volume, and IgA and liver histology when obtainable.
Abstinence is the most important aspect of treatment. Newer drugs such
as acamprosate and naltrexone are used to reduce alcohol craving.
Vitamin supplements and nutrition are vital while corticosteroids have
a role in acute alcoholic hepatitis where there is no evidence of
gastrointestinal haemorrhage or sepsis. Liver transplantation has
excellent results in abstinent patients with end stage liver disease
but there are concerns about recidivism after transplant
Kim SW
Opioid antagonists in the treatment of impulse-control disorders
J Clin Psychiatry; 59(4); 159-164; 1998
BACKGROUND: Symptoms of impulse-control disorders are generally
refractory to psychotherapeutic or pharmacologic treatments. Recent
study results suggest that opioid antagonists may reduce human urges,
one of the core symptoms of impulse-control disorders. The author
discusses the rationale for and the potential utility of the opioid
antagonists in the treatment of impulse-control disorders.
METHOD:
Work by preclinical and clinical investigators on the subject of
motivation and its contextually relevant behavior is reviewed. The
review includes the pharmacologic modulation of the motivation or
drive and subsequent changes in behavior in animals and humans. On the
basis of these reviews, the author prescribed naltrexone for up to 9
months to 15 patients who had impulse-control disorder, and 3 select
cases are reported.
RESULTS: Naltrexone was generally well tolerated,
and there were no hepatic side effects. Naltrexone appears to reduce
urge-related symptoms and decreases the problematic behaviors such as
pathological gambling. The effect appears to be sustained. In general,
50 mg/day of naltrexone was not effective. Most patients required
higher doses. Results were similar in the 12 other cases not reported
here.
CONCLUSION: Naltrexone may be of use in select impulse-control
disorder patients. Other opioid antagonists such as nalmefene also
need to be tested. Until controlled study data become available, the
present report should be viewed as preliminary
Bertolotti M, Ferrari A, Vitale G, et. al.
Effect of liver cirrhosis on the systemic availability of
naltrexone in humans
J Hepatol; 27(3); 505-511; 1997
BACKGROUND/AIMS:
Naltrexone is a competitive opiate antagonist with high hepatic extraction.
It is used for detoxification treatment for heroin addicts and has been proposed
as a possible treatment of pruritus in cholestasis. Such patients are likely to have impaired
liver function, underscoring the need to understand the
pharmacokinetic behavior of naltrexone in liver disease. These studies
were undertaken to evaluate the effect of liver cirrhosis on the
plasma time-course of naltrexone.
METHODS: A total of 18 patients were
investigated: seven migraine patients with normal liver function
regarded as controls and 11 patients with liver cirrhosis (six with decompensated disease and five with preserved liver function). A bolus
of 100 mg of naltrexone was administered orally in the morning, after
an overnight fast. Blood samples were taken in basal conditions and at
fixed intervals, up to 24 h after administration. Serum levels of
naltrexone and of its major active metabolite, 6 beta-naltrexol, were
assayed by reversed-phase HPLC analysis.
RESULTS: In control subjects,
circulating concentrations of naltrexone were always much lower than
those of 6 beta-naltrexol (area under the curve: naltrexone, 200 +/-
97 ng/ml x 24 h; 6 beta- naltrexol, 2467 +/- 730 ng/ml x 24 h, p <
0.01). In severe cirrhosis serum levels of 6 beta-naltrexol increased
more slowly, so that circulating levels of naltrexone during the first
2-4 h after drug intake were higher than those of 6 beta-naltrexol (6
beta- naltrexol/naltrexone ratio at 2 h: controls, 10.91 +/- 4.80;
cirrhosis, 0.39 +/- 0.18, p < 0.01). The area under the curve for
naltrexone (1610 +/- 629 ng/ml x 24 h) was significantly greater than
in controls, whereas that for 6 beta-naltrexol (2021 +/- 955 ng/ml x
24 h) was not significantly different. Patients with compensated
cirrhosis showed an intermediate pattern. No differences in
elimination half-life of the two drugs were detected among the groups.
CONCLUSIONS:
Our data suggest the occurrence of important changes in
the systemic availability of naltrexone and 6 beta-naltrexol in liver
cirrhosis; such alterations are consistent with lesser reduction of
naltrexone to 6 beta-naltrexol and appear to be related to the
severity of liver disease. This must be considered when administering
naltrexone in conditions of liver insufficiency
Sax DS, Kornetsky C, Kim A
Lack of hepatotoxicity with naltrexone treatment
J Clin Pharmacol;34(9); 898-901; 1994
Naltrexone, a specific opiate receptor antagonist, is used
clinically in the treatment of heroin addiction and more recently, for
the treatment of dyskinesia associated with Huntington's disease (HD).
Naltrexone may act as a potential hepatotoxin, as reflected in the
elevation of transaminase levels. However, one study concluded that,
for a brief treatment period of 12 weeks, there is no contraindication
to naltrexone treatment based solely on increased hepatic enzyme
values. This study monitored liver transaminase levels, in ten HD
patients receiving daily doses, between 50 mg/day and 300 mg/day, of
naltrexone for periods of 10 to 36 months. Serum glutamic oxalacetic
transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT)
levels were obtained before treatment and at intervals of 1 to 4
months during treatment. Only one of the ten patients treated with
naltrexone had increased levels of both SGOT and SGPT, whereas one
other patient showed elevated levels of SGPT. These elevations, which
initially appeared dose related decreased to normal limits with
continued treatment. Because many of the patients were receiving other
medications, a combination of drugs with naltrexone may contribute to
the increased transaminase levels seen in two of the patients. In
summary, 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
Bryant HU, Kuta CC. Story JA, Yim GK
Stress- and morphine-induced elevations of plasma and tissue cholesterol in
mice: reversal by naltrexone
Biochem Pharmacol; 37(19); 3777-3780; 1988
Our earlier studies indicated that stress-induced facilitation of
gallstone formation could be prevented by the opiate antagonist
naltrexone. In view of the possible link between gallstone formation
and atherosclerosis, the present study examined the possibility that
endogenous opioids might also mediate stress-induced hypercholesterolemia. A 28-day immobilization stress schedule was used
to induce increases in plasma, aortic and liver cholesterol of mice
maintained on a high cholesterol diet. These stress-induced increases
in plasma, hepatic and aortic cholesterol were reversed by
pretreatment with the opiate antagonist, naltrexone (1 mg/kg). Exposure of mice to morphine (0.1% in the drinking water for 28 days)
resulted in elevations of plasma, liver, and aortic cholesterol
levels, similar to those observed following immobilization. In
contrast, chronic exposure to the peripherally restricted opiate
agonist, loperamide (0.1% in the drinking water for 28 days), was
ineffective. The antagonism by naltrexone and duplication by morphine
but not loperamide suggest that stress-induced hypercholesterolemia
may require the activation of central endogenous opioid systems
Brahen LS, Capone TJ, Capone DM
Naltrexone: lack of effect on hepatic enzymes
J Clin Pharmacol;28(1); 64-70; 1988
A number of studies have established the clinical efficacy of
naltrexone in the treatment of opiate addiction. However, questions
have been raised regarding its hepatotoxic potential and warnings have
been given prominence in the package insert regarding its use for
those with even less severe liver disease. The current study monitored
53 male patients receiving naltrexone 350 mg weekly for 12 weeks. The
lactic acid dehydrogenase (LDH) and serum glutamic oxalacetic
transaminase (SGOT) levels were determined at pretreatment and at
monthly intervals thereafter for three months. LDH and SGOT were found
to drop significantly from baseline over this three-month period. This
decrease appeared most notable for those with pretreatment hepatic
enzyme levels exceeding the normal range. Moreover, changes in hepatic
enzyme levels were not consistently correlated with the patients use
of illicit drugs such as opioids, benzodiazepines, cocaine,
barbiturates, and amphetamines. Based on these data, we have concluded
that contrary to cautions implied in the naltrexone package insert,
the benefit of admitting patients with the sole problem of elevated
hepatic enzymes generally exceeds the risk
Mitchell JE; Morley JE; Levine AS; Hatsukami
D; Gannon M; Pfohl D
High-dose naltrexone therapy and dietary counseling for obesity
Biol Psychiatry;22(1); 35-42; 1987
There is considerable evidence that
antagonism of the endogenous opioids will suppress food intake in a variety of
animal species. The authors report a double-blind, placebo-controlled trial of
the long-acting, orally active narcotic antagonist naltrexone in the promotion
of weight loss in obese male subjects who were also undergoing dietary
counseling for weight reduction. Subjects received medication (naltrexone,
300 mg/day or placebo) for 8 weeks following an initial 2-week single-blind
placebo phase. The results failed to demonstrate an advantage for the active
drug. However, the naltrexone was associated with [reversible] hepatotoxicity
when used at this dosage in this population
James RC; Goodman DR; Harbison RD
Hepatic glutathione and hepatotoxicity: changes induced by selected narcotics
J Pharmacol Exp Ther; 221(3;:708-714; 1982
Propoxyphene and morphine lowered hepatic glutathione and increased serum
glutamic-pyruvic transaminase (SGPT) activity when administered to male mice.
Maximal changes were seen at 3 to 6 hr after administration, but the effects
lasted for as long as 18 hr. Morphine-induced hepatic changes potentiated both
acetaminophen and cocaine-induced hepatotoxicity. Naltrexone, a narcotic
antagonist, abolished the glutathione depletion produced by both propoxyphene
and morphine, but did not alter the propoxyphene-induced elevations of SGPT.
Naltrexone also was tested against other narcotic agonists we have previously
demonstrated to be hepatotoxic. Naltrexone pretreatment of antagonized L-alpha-acetylmethadol
(LAAM)-induced depletion of glutathione and elevations of SGPT. Similarly,
naltrexone antagonized norLAAM-induced depletion of glutathione and elevations
of SGPT, but only lessened the magnitude of the changes induced by SKF525-A. The
narcotic agonists morphine, LAAM, norLAAM and propoxyphene lower hepatic
glutathione and induce hepatocellular damage, but these two effects appear to be
unrelated
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