Pain Specialists and Addiction Medicine Specialists Unite to Address Critical Issues

Russell K. Portenoy, MD

American Pain Society Bulletin; March/April 1999; Vol. 9; Num. 2
URL: http://www.ampainsoc.org/pub/bulletin/mar99/president.htm 

The leadership of the American Pain Society, the American Academy of Pain Medicine, and the American Society of Addiction Medicine has now formally recognized the need for this dialogue and for joint action on critical issues. At a preconference meeting initiated by the American Society of Addiction Medicine, the decision was made to explore development of a coalition, the goal of which will be to prioritize and begin implementing projects that will have a direct impact on the members of all three organizations and their constituencies.

All pain specialists should be familiar with the rapidly evolving linkages between pain and chemical dependency. They touch on an extraordinarily broad range of matters, including advances in neurobiology, the undertreatment of pain (particularly in special populations like the chemically dependent), the clinical use of opioid drugs for pain management or the treatment of addiction, the potential therapeutic use of other abusable drugs such as psychostimulants, concerns about education and professional training, and the impact of laws and regulations on patient care. Scientific exploration of the neurobiological substrates of pain and chemical dependency exposes remarkable parallels. Studies of opioid systems that focus on physical dependence, tolerance, and nonanalgesic effects are directly relevant to both fields, as are studies of other neural systems, such as the adrenergic and cannabinoid systems. New investigative tools are driving progress. These include molecular biological techniques, functional neuroimaging, and a variety of new experimental models that evaluate craving, tolerance, and other relevant phenomena. Advances will accelerate as basic scientists identified for their work in the area of pain mechanisms interact with those identified for work in the addictions.

On the clinical side, the issue that probably brings these fields together in the most profound way is the undertreatment of pain. To the extent that undertreatment involves the inadequate use of opioid drugs, it is sustained in part by stigma, ignorance, and fear of phenomena associated with chemical dependency. Opioids are underused even in those conditions—cancer pain, pain related to AIDS, and pain in the dying—for which there is widespread consensus that aggressive opioid pharmacotherapy is the best approach. Studies reveal that cancer and AIDS patients with histories of chemical dependency are relatively more likely to be undertreated than those without this history.

The professional communities involved in pain management and the addictions are slowly coming to realize that they face common barriers to optimal pain management. The proper use of opioid drugs is an organizing principle. With opioid therapy complicated in both fields by misapprehensions and myths, there is an abiding need to disseminate information about opioid-related phenomena and to define the necessary terms in a manner that will not isolate pain management from addiction or contribute to the stigmatization of either the drugs or the populations requiring them.

Four types of phenomena exemplify the accommodations that must be made to further these goals (Portenoy & Payne, 1997):

NONANALGESIC OPIOID EFFECTS. There continues to be widespread confusion about the nature of opioid-related nonanalgesic CNS effects. It is widely acknowledged that opioids may alter consciousness, cognition (e.g., memory and attention), perception, and mood. Uninformed expectations about these effects can contribute to stigma and negatively influence attitudes about therapeutic potential. For inexperienced clinicians and the public at large (whose frame of reference is often derived from the media), the expected response to an opioid is impaired consciousness, impaired cognition, variable changes in perception, and euphoric mood (i.e., the "rush"). For the clinician whose frame of reference is short-term opioid dosing for acute pain, the expectation is that the drug will impair consciousness, impair cognitive ability, produce variable changes in perception, and yield mood effects that may be described as contentment, no change, or actual dysphoria. Remarkably, specialists in addiction medicine and pain specialists have an entirely different expectation for opioid therapy, derived from experience in methadone maintenance or long-term opioid therapy for pain, respectively. Specifically, it is expected that the nonanalgesic CNS effects during chronic dosing will be clinically inapparent. If the therapy is working as it should, the patient appears normal. Those who work in pain and those who work in addiction must emphasize this reality. PHYSICAL DEPENDENCE. Physical dependence is a pharmacological effect of a drug defined by the occurrence of an abstinence syndrome following administration of an antagonist drug or abrupt dose reduction or discontinuation. The conventional wisdom among those in addiction medicine is that physical dependence is important in the pathogenesis of addiction because individuals who use opioid drugs undergo a transition from seeking a "high" to both seeking a high and avoiding withdrawal. Many clinicians who treat patients with pain also perceive physical dependence to be a problem. They assume that the phenomenon could contribute to aberrant drug-related behavior or could possibly sustain pain or disability. There is another perspective, however, which is now shared by many pain specialists and addiction specialists. Physical dependence is usually clinically unimportant as long as abstinence is avoided, and, in fact, the major problem with this phenomenon is its mislabeling by clinicians. The term addiction should never be applied solely to the perceived capacity for abstinence. This serious error stigmatizes the patient and the therapy. The capacity for withdrawal should always be labeled physical dependence. Pain specialists and addictionists alike must work to clarify this nomenclature. TOLERANCE. Tolerance is the diminution of drug effect over time as a consequence of exposure to the drug. It can refer to any drug effect and may be related to any number of diverse processes, including learning (so-called associative tolerance), changes in drug concentration (pharmacokinetic or dispositional tolerance), or changes in receptors and postreceptor processing (pharmacodynamic tolerance). For many in the addiction community, tolerance is viewed as a major problem that drives addiction by producing a need for progressively higher doses to achieve desired psychic effects. Interestingly, addictionists implicitly recognize the complexity of the phenomenon by acknowledging that tolerance to the "blockade" effects of methadone does not appear to occur during methadone maintenance. Many clinicians, including some who specialize in pain management, also assume that tolerance is a common problem during long-term opioid therapy for painful disorders and that it precludes successful treatment for many patients. To clarify the nature of the phenomenon, pain specialists and addictionists must begin to describe tolerance as a complex process that may or may not be clinically desirable. During opioid therapy for pain, tolerance to side effects is beneficial and is presumably the reason that patients can function normally. Tolerance to analgesia would be a problem, but fortunately this process seldom appears to be the driving force for dose escalation. In stable disease, opioid doses typically plateau for prolonged periods. Moreover, there is no evidence in pain populations that the occurrence of tolerance drives the development of addiction. Tolerance is a concern in patients with addictive disease, whose drug use is driven by the need to achieve some psychic effect other than analgesia, and it could be an issue for some opioid-treated pain patients whose need for higher doses cannot be explained by progressive pain. Nonetheless, the phenomenon is actually highly complex, and the dangers associated with it have been overstated. ADDICTION. The definition and description of the term addiction must be carefully considered. This is one of the most significant challenges for specialists in pain or chemical dependency. Published definitions of the term are inadequate when applied to populations with pain. Addiction is best defined as a behavioral pattern characterized as loss of control over drug use, compulsive drug use, and continued use of a drug despite harm. Drug-related behaviors must continually be evaluated for evidence that suggests the occurrence of these outcomes. It is clear that aberrant drug-related behaviors exist on a spectrum ranging from egregious behavior (e.g., injecting an oral formulation or concurrently using illicit drugs) to behavior that is more difficult to interpret in a clinical context (e.g., aggressive complaining about the need for higher doses or unsanctioned dose escalation once or twice in the setting of uncontrolled pain). In pain management, aberrant drug-related behavior has an important differential diagnosis, which certainly includes not only addiction, but also so-called pseudoaddiction (first described by Weissman and Haddox [1989] in the cancer population), other psychiatric conditions, family problems, criminal intent, and other events. Given the existence of this differential diagnosis, addiction may not be easily diagnosed in patients with or without histories of chemical dependency when unrelieved pain interacts with clinical decision making during therapeutic administration of an opioid. Pain specialists and addictionists must coalesce around a practical and clinically appropriate definition of addiction and must help promulgate it to clinicians and nonclinicians alike. As noted, other critical issues further define the linkage between pain and chemical dependency. With increases in the therapeutic use of nonopioid drugs having the potential for abuse, including psychostimulants, benzodiazepines, barbiturates, cannabinoids, antidepressants, and antihistamines, the issues highlighted by the opioids will extend beyond opioid therapy. A very controversial issue—the potential therapeutic role of marijuana—underscores the need for professional collaboration in addressing these issues. Pain specialists and addictionists also share profound concerns about education, training, and policy. At the present time, pain specialists know little about addiction medicine, addiction medicine specialists know little about pain, and nonspecialists know little about either. The success of a conference on pain and chemical dependency demonstrates the need for information sharing among professionals. Finding additional venues for education and training will be a focus of the coalition that develops among the American Pain Society, the American Academy of Pain Medicine, and the American Society of Addiction Medicine.

This coalition may also choose to address the ongoing concern that laws and regulations intended to stem abuse may actually impede the legitimate medical use of potentially abusable drugs in either pain management or the treatment of addiction. It is critical that those who treat patients with pain, patients with addictive disease, or patients with both pain and chemical dependency continue a dialogue with those in the regulatory community or law enforcement. This will help in the process of destigmatization and, it is hoped, lead to regulations and laws that reduce diversion and abuse but do not inadvertently cause inappropriate undertreatment of pain or addiction.

References

Portenoy, R.K., & Payne, R. (1997). Acute and chronic pain. In J.H. Lowenson, P. Ruiz, & R.B. Millman (Eds.), Comprehensive textbook of substance abuse (3rd ed., pp. 563-590). Baltimore: Williams & Wilkins.

Weissman, D.F., & Haddox, J.D. (1989). Opioid pseudoaddiction: An iatrogenic syndrome. Pain, 36, 363-366.