Clinicians should recognize that virtually any drug acting on the central nervous system or any route of drug administration can be abused. The effective management of patients with substance abuse histories requires a comprehensive approach that accounts for the biological, chemical, social, and psychiatric aspects of substance abuse and addiction. This approach goes beyond simply avoiding certain drugs or routes of administration and provides practical means to manage risk during cancer treatment.
Although the most difficult issues in cancer care typically arise in those who are actively abusing alcohol(Drug information on alcohol) or other drugs, the following principles can also apply to patients who are in drug-free recovery and those who are in methadone(Drug information on methadone) maintenance programs. The guidelines below are likely to be most helpful in the management of the active drug abuser. The management, recognition, and documentation of addiction-related outcomes may be helpful and necessary at various times in all pain treatments.
Recommendations for the long-term administration of potentially abusable drugs, such as opioids, to patients with a history of substance abuse are based solely on clinical experience. Studies are needed to determine the most effective strategies and to empirically define patient subgroups who may be most amenable to different approaches. The following guidelines broadly reflect the types of interventions that may be considered in this clinical context (Table 1).
Involve a Multidisciplinary TeamIn the population of patients with cancer and substance abuse, pain and symptom management often is complicated by multiple medical, psychosocial, and administrative problems. A team approach can be very useful in addressing these problems and avoiding provider burn-out. The most effective team may consist of an oncologist, a physician with expertise in pain/palliative care, nurses, social workers, and, if possible, a mental health professional with expertise in addiction medicine.
Set Realistic Goals for TherapyThere is a high recurrence rate for drug abuse and addiction. The risk of relapse is higher because of the stress associated with cancer and the ready availability of centrally acting drugs. Complete prevention of relapses may be impossible in such a setting. If there is a general understanding that compliance and abstinence are not realistic, conflicts with staff in terms of management goals may be reduced. Rather, the goal of team management might be the creation of a structure for therapy that includes sufficient social/emotional support and limit-setting to contain the harm done by relapses and to render them less frequent.
Severe substance-use disorder and comorbid psychiatric diagnoses may prevent a small subgroup of patients from complying with the requirements of oncologic therapy. In such circumstances, clinicians must reestablish limits on multiple occasions and attempt to develop an increasing variety and intensity of supports. Frequent team meetings and consultations with other clinicians may be needed. Ultimately, appropriate expectations must be clarified and failing therapy modified.
Evaluate and Treat Comorbid Psychiatric DisordersThe comorbidity of personality disorder, depression, and anxiety disorders in alcoholics and other patients with substance-abuse histories is extremely high. The treatment of anxiety and depression can increase patient comfort and possibly diminish the likelihood of relapse or aberrant drug-taking.
Prevent or Minimize Withdrawal SymptomsMany patients with a history of drug abuse consume multiple drugs, and therefore a complete drug-use history must be elicited to prepare for the possibility of withdrawal. Delayed abstinence syndromes, such as may occur following abuse of some benzodiazepine drugs, may pose a particular diagnostic challenge. Clinicians must be familiar with the signs and symptoms associated with withdrawal from opioids and other drugs.
Consider the Therapeutic Impact of ToleranceAs mentioned in part 1 of this article (April 1998, p 517), tolerance is a complex phenomenon,[2,3] and its impact on clinical management in this context is likely to be highly variable. Patients who are actively abusing drugs may have sufficient drug tolerance to influence the use of prescription drugs subsequently administered for an appropriate medical indication.
It is possible that exposure to a drug of abuse will induce sufficient tolerance to the desired therapeutic effects and make pain management more difficult. A survey of hospitalized patients on methodone maintenance failed to identify any difference in the need for postoperative analgesics between those with and without a substance abuse history. However, anecdotal experience suggests that some actively abusing patients who develop a therapeutic need for an opioid or a sedative-hypnotic drug do require relatively high initial doses or need rapid dose escalation to establish or retain therapeutic effects.
Similarly, clinical observation suggests that some patients receiving methadone maintenance require relatively higher opioid doses to treat acute pain and relatively rapid dose escalation at the start of therapy to identify a useful dose for chronic cancer pain management. From a practical perspective, the clinician must not only be cautious in estimating the degree to which tolerance may be operating but also remain cognizant of the potential need for relatively higher doses. The starting dose of a therapeutic drug should be conservative, and rapid dose titration with careful monitoring should be available.
Apply Appropriate Pharmacologic Principles to Treat Cancer PainTo optimize long-term opioid therapy, well-accepted guidelines for cancer pain management must be applied.[5,6] These guidelines emphasize the importance of patient self-report as the basis for dosing, individualization of therapy to identify a favorable balance between efficacy and side effects, and the value of monitoring over time. The concurrent treatment of side effects can optimize the balance between analgesic and adverse effects.
The most important guideline for long-term opioid therapy, individualization of the dose without regard to its size, can be problematic in populations with histories of substance abuse. Although it may be appropriate to exercise caution in prescribing potentially abusable drugs to these populations, the decision to forego the principle of dose individualization without regard to absolute dose may increase the likelihood of undertreatment.[8,9] The unrelieved pain that results can, in turn, lead to the development of aberrant drug-related behaviors. Although these behaviors might be best understood as pseudoaddiction (ie, distress and drug-seeking behavior in patients with unrelieved cancer pain), their occurrence confirms clinicians fears and encourages even greater caution in prescribing.
Given the dual role of methadone as a treatment for opioid addiction and as an analgesic, clinicians who manage patients with substance-abuse histories must understand the pharmacology of this drug. The differences in the dosing of methadone for its two indications are striking.
Abstinence can be avoided and opioid craving reduced with a single daily dose. This is consistent with the long elimination half-life of this drug. Analgesic effects after a dose, however, are usually much briefer than would be expected, given the drugs half-life. Indeed, one double-blind study demonstrated that the duration of analgesia after a single dose of methadone is comparable to that after morphine(Drug information on morphine), an opioid with a short half-life. Although there are exceptions, most patients appear to require a minimum of four doses of methadone per day to achieve sustained analgesia.
Patients who are receiving methadone maintenance as a treatment for opioid addiction can be administered methadone as an analgesic outside of the guidelines of the addiction treatment program. This typically requires a substantial change in therapy, including dose escalation and multiple daily doses.
Although the management of such a change does not pose difficult problems from a pharmacologic perspective, it can create considerable stress for the patient and the clinicians involved in the treatment of the addiction disorder. Some patients express a lack of faith in the analgesic efficacy of methadone because the drug has been labeled as addiction therapy, rather than a pain therapy. Others wish to continue the morning dose for addiction, even if treatment during the rest of the day uses the same drug at an equivalent or higher dose. Some physicians who work at methadone clinics are willing to stay involved and prescribe opioids, including methadone, outside of the program, and others wish to relinquish care.
Select Drugs and Administration Routes for the Symptom and SettingAs discussed previously, there is little reason to believe that the common clinical lore about the differences in addiction liability between short-acting and long-acting drugs or among different routes of administration are relevant to the management of palliative therapies in populations without substance abuse. In the population of known substance abusers, however, it may be prudent to consider these observations.
There is no disadvantage to the use of a long-acting preparation, and it is possible on theoretical grounds that the rapid onset and decline of effects associated with short-acting drugs could contribute to the development of aberrant drug-related behaviors. Accordingly, it is appropriate during opioid therapy to rely, if possible, on the use of long-acting drugs, such as oral methadone, oral controlled-release or sustained-release opioid formulations, and transdermal formulations.
Recognize Specific Drug Abuse BehaviorsAll patients who are prescribed potentially abusable drugs must be monitored over time for the development of aberrant drug-related behaviors. The need for this monitoring is especially strong in patients who have a remote or current history of substance abuse, including alcohol abuse. If there is a high level of concern about such behaviors, monitoring may require relatively frequent visits and regular assessment of significant others who can provide observations about patients drug use.
To facilitate the early recognition of aberrant drug-related behaviors in patients who have been actively abusing drugs in the recent past, regular screening of urine for illicit or licit but unprescribed drugs may be appropriate. The patient should be informed about this approach, which should be explained as a method of monitoring that can be reassuring to the clinician and provide a foundation for aggressive symptom-oriented treatments. Presented in this way, it is a technique that enhances rather than threatens the therapeutic alliance with the patient. Patients who protest excessively may be unwilling or unable to enter a collaborative relationship in which the clinician can be confident of responsible drug-taking by the patient. Without such confidence, the clinician is unlikely to respond to the patients unrelieved symptoms with aggressive therapies.
Utilize Nondrug Approaches as AppropriateA variety of nondrug interventions may be useful in helping patients cope with the cancer treatment. These include educational interventions designed to assist patients in communicating with the staff about pain and negotiating the complexities of the medical system, as well as numerous cognitive techniques that enhance relaxation and aid in coping. Nondrug interventions may be helpful adjunctive therapies but should not be seen as substitutes for drugs targeted to pain, depression, anxiety, or other physical or psychological symptoms.