November 30, 1999
It is axiomatic in palliative care that suffering occurs in physical, emotional, practical, and spiritual domains and that each of these domains has an impact on any given symptom.1 Although in many ways these domains are more complicated in patients with substance use histories, the approach to palliative care for the substance user is fundamentally the same as for any other patient. Given the importance that substance use plays in the HIV epidemic, however, it is important that care providers explore, understand and address these complications. Clinicians can often become frustrated with and alienated from substance-using patients, in whom self-destructive behaviors and care providers' own negative attitudes can interfere with treatment success. However, by attending to the specific clinical issues pertaining to substance use and integrating these into a palliative care treatment plan, providers can effectively care for this challenging population.
If a patient has a history of or is currently using alcohol or illicit drugs, care providers must know. These issues should be, therefore, part of every history taken by members of the health care team and can be readily addressed in the routine primary care encounter (see Table 11-1, PDF).2 It is a mistake to raise issues of substance use only with patients who arouse suspicions or fit certain stereotypes. Care should be taken, however, to ensure that the patient or family members are not made to feel judged or guilty during these discussions.
It is often easiest to include questions regarding drug use among questions regarding smoking and alcohol use in a straightforward, matter-of-fact manner. Physical and laboratory examinations can also be helpful. Track marks, evidence of soft tissue infections, nasal septum erosion, liver function abnormalities, tremor, or asterixis can support a diagnosis of substance use.
Finally, a social history remarkable for repeated incarcerations, violence, inability to sustain long-term interpersonal relationships, sporadic employment and/or a family history of substance use should raise the provider's index of suspicion for substance use.
If a history of substance use is identified, further exploration is needed. It is important to be aware that poly-substance use is common. At a minimum, the type of substance(s), amount, route of administration, frequency of use, and medical complications, including signs of tolerance and dependence should be understood (see below). If a patient has been in substance use treatment, the palliative care team should know the approach that was used and its impact on the patient's drug use. In these circumstances, the palliative care team should include an expert in treating addictions.
General Medical Care
While this chapter does not attempt to review the myriad medical complications of substance use and HIV, it is important that the palliative care provider be aware of the scope of issues that he or she may face and be prepared to seek consultation when necessary.3, 4
Substance users can be at higher risk for diseases besides HIV/AIDS. Hepatitis B, C, and delta are transmitted parenterally, as are bacteria causing endocarditis, soft tissue infection and other infections. Tuberculosis and sexually transmitted diseases are more common in this population and must be ruled out. Chronic lung disease associated with exposure to substances used to "cut" cocaine and heroin and chronic liver disease associated with alcohol can make provision of palliative care medically complex.
Active drug users are at risk for withdrawal (from opiates, alcohol, barbiturates and benzodiazepines), which can be a life-threatening emergency. Cocaine, particularly when injected or smoked, can cause cardiac arrhythmias, hypertension, hyperpyrexia, rhabdomyolysis, and cerebral or coronary artery vasospasm. Substances that suppress consciousness and respiration can induce coma and death. Opiates, in addition, can cause non-cardiogenic pulmonary edema.
Pain is often poorly managed in the substance-abusing patient or in the patient with a history of substance use.5 This can be because pain is not recognized as such and is interpreted as manipulation or "drug-seeking;" because unique predispositions to pain are not understood; or because of ignorance of basic principles of addiction and/or pain management. To manage pain appropriately, providers need a systematic and thoughtful approach.
Substance Use and Pain
It must first be understood and accepted that a history of substance use does not preclude someone from having real pain. In many cases, in fact, substance use may predispose a patient to experience physical pain (secondary to trauma, chronic venous insufficiency, infections, alcoholic or nutritional neuropathies, etc.) or to have pain that is difficult to control for a variety of reasons. Patients who have developed tolerance to opiates may require doses of narcotic medications considerably higher than non-tolerant patients, and this may make some providers uncomfortable. Additionally, it has been shown that some substance users treated with methadone may have a lower pain threshold than others.6 Finally, the profound emotional, practical, and even spiritual complications of substance use contribute to pain symptoms and must be addressed to manage pain successfully.
The substance-using patient may contribute to the difficulty of treating pain by his or her own behavior. Trust between clinician and provider is fundamental to mobilizing an effective treatment regimen. If the patient has lied, manipulated, sold prescription drugs or otherwise created cause for mistrust, such a negative atmosphere is not easily overcome. In these instances, the provider should discuss the situation directly and frankly with the patient, articulate reasonable limits, develop a written contract and move on. Such a contract should stipulate the following:
While these efforts can be very effective in helping to prevent manipulation and abuse of prescribed narcotics, abuse can sometimes still occur. It is important for providers to recognize the types of behaviors suggestive of abuse, in order to be able to prevent and address these problems (Table 11-3, PDF).5
While patients' own behaviors can damage trust, a provider can also unintentionally damage trust in his or her relationship with the patient. A provider who does not take a complaint of pain seriously simply because of a patient's socioeconomic status, race or history of substance use is violating the implicit trust that the patient places in his or her hands. Several studies have demonstrated that nonwhite patients are more likely to have pain underdiagnosed and undertreated than white patients.7 It has also been shown that pharmacies in poor minority neighborhoods may not stock narcotic medications and thus make access to pain treatment more difficult.8 As will be discussed below, substance-using patients often have long histories of negative interactions with the health care system. Provider prejudices, when brought to the palliative care of an HIV-infected patient, can inflict further damage precisely at a time when trust and healing are most needed.
Pharmacologic Properties and Physiologic Impact of Substances
Providers must know what substance(s) the patient is using, the pharmacologic properties, and the physiologic impact. A patient with a chronic addiction to alcohol will have different physiologic response to a given dose of an opiate than someone who has become tolerant to heroin. Similarly, someone with alcohol-related peripheral nerve damage might experience HIVrelated neuropathy more severely than a cocaine user.
Care must be taken to precisely describe the patient's use of the substance. Tables 11-4 (PDF) and 11-5 (PDF) provide definitions of commonly used terms in this regard.5, 9-11 Proper use of these terms allows clear communication among all members of the palliative care team (including addiction specialists) and forms the basis of an explicit clinical rationale for both pain and addiction treatment decisions.
Table 11-6 (PDF) presents particular issues that arise in the care of patients being treated in methadone maintenance programs. It is always best to keep pain management and addiction treatments as separate items on the problem list with distinct strategies and approaches.12 However, at the same time, both pain management and addiction treatment must be integrated into an overall plan of care.
The baseline methadone dose should never be assumed to be sufficient to treat pain. Furthermore, increasing a patient's daily methadone dosage for purposes of treating pain has serious drawbacks, as follows:
Near the end of life, inpatient or home-bound patients on methadone maintenance may benefit from a less rigid approach. A total daily opiate dose (e.g., morphine, hydromorphone) can be given via continuous intravenous or subcutaneous infusion pump.
General Pain Management Issues
In patients with substance use histories, as with other patients, the provider must develop an understanding of the pathophysiology of the pain in question and a rational, incremental approach to its pharmacological management. (See Chapter 4: Pain.) After taking a careful history of the pain complaint (site; quality; exacerbating and relieving factors; temporal quality; onset; associated symptoms and signs; impact on life and psychology; and effect of current treatments), the provider can determine whether the pain is of nociceptive or neuropathic origin. This distinction is important as it can have treatment implications. Nociceptive pain results from stimulation of afferent receptors and can cause myriad painful sensations: localized or diffuse; somatic (involving skin, muscle, bone and soft tissue) or visceral; mild to severe. Neuropathic pain derives from damaged or otherwise compromised nerves and tends to result in shooting, stabbing, burning, electric shock-like pain, or discomfort that is caused by minimal stimulation to the skin (allodynia).
As is true in any patient, effective pain management in the substance-using patient involves multiple modalities and usually requires contributions from all members of the palliative care team. The pharmacological approach is best guided by the World Health Organization (WHO) three-tiered ladder -- starting with non-narcotic analgesics (step one); followed by weak narcotics (step two); and finally moving to strong opioids (step three). (See Figure 4-1 in Chapter 4: Pain.) Adjuvant analgesics can be added at any step (e.g., for neuropathic pain). It is important to be aware, however, that in a patient who has developed tolerance to narcotics, strong opiates (step three) may be needed sooner, at greater frequency, and at higher doses, than would otherwise be expected. It is better for the primary care provider to work and be comfortable with one or two drugs in each class (doses, pharmacokinetics, conversions, side effects, interactions etc.) than to have only a superficial knowledge of all of them. As a general rule, it is best to push lower level treatment to the maximum before advancing to the next level. In cases of moderate to severe pain, therapy can rightly begin at step two.
While taking reports of pain seriously, providers should also act to minimize the likelihood of abuse. This often means opting for the alternative that is least tempting to the patient, avoiding use of a stronger, more readily abused drug for mild to moderate pain if an alternative is available that is less likely to be abused. For example, codeine is weaker, less euphorigenic, more constipating, and of lower "street value" than oxycodone, morphine, or hydromorphone. Although this is not a firm rule, long-acting drugs tend to be less likely to be abused than short-acting ones, and certain formulations (e.g., the transdermal fentanyl patch) may be less prone to abuse than others (e.g., brand-name oxycodone pills, which have a higher "street value" than generic oxycodone).
As noted above, the concepts of tolerance and dependence are very important in assessing and treating pain in substance users. (See Tables 11-4, PDF and 11-5, PDF.) Because of tolerance, patients will have higher narcotic requirements than patients who are opioid-naive, meaning that opioids will have to be prescribed at higher dosages and more frequently. This is sometimes counterintuitive to providers who are reluctant to prescribe opioids to patients with histories of opioid abuse. However, unless the provider accounts for the patient's actual dosage needs, the treatment will be guaranteed to fail. Moreover, a common scenario which then unfolds is that providers may interpret patients' requests for higher doses or early prescription refills as signs of drug-seeking, thus confirming their prejudices about manipulative behavior in substance users, when in fact this patient response is entirely predictable based on the pharmacology of opioid medications.
The concept of dependence is important in that the symptoms of drug withdrawal (which may include malaise, musculoskeletal pain, and abdominal pain) may need to be distinguished from the underlying pain disorder in patients who become opioid-dependent and may require additional intervention (e.g., use of longer-acting drugs) to ensure a steady-state over the 24-hour dosing period.
When switching between opioids and analgesics clinicians must be familiar with conversions between different drugs in order to maintain a constant level of analgesia and avoid side effects. (See Chapter 4: Pain.) As cross-tolerance between opioids is not always complete, however, the initial dose of a new opioid should be about half of the calculated dose and the patient observed for side effects. Rapid scale-up of the medication can follow.
Meperidine (which has long-acting metabolites) and mixed agonist-antagonist agents that can precipitate withdrawal such as pentazocine and butorphanol should generally be avoided. Providers should also be careful when prescribing narcotic combinations that include potentially hepatotoxic agents like acetaminophen (e.g., fixed-combination oxycodone or codeine plus acetaminophen). In many cases, the dose-ceiling for these drugs is due to the acetaminophen (for which the daily dose should not exceed 4 gm/day and in some patients even less), and not the opioid itself. This is particularly true in a drug-using population with HIV already at high risk for hepatitis.
Neuropathic pain also can be pharmacologically managed using the WHO ladder. Effective management, however, often involves more aggressive use of adjuvant treatments, particularly those known to act on the central nervous system: anti-depressants, anti-convulsants, and others. (See Chapter 4: Pain.)
Route of administration of opiates is also an important issue in this population. Some patients whose substance use is in remission may strongly object to administration of any drug using a needle and be much more comfortable with oral or transdermal preparations. In other cases, when there is concern that medications may be sold on the street (either by the patient or household members), long-acting, transdermal, and generic formulations are best, even though misuse can still occur with all of these options. Indwelling catheters pose particular problems in that they can be, and are, misused by some patients. In these cases, a percutaneous infusion pump may be a better option.
Physicians often fear that they are being manipulated to over-prescribe controlled substances. Alternatively, they may be concerned that they will create or re-establish an addiction. There are no easy answers to these dilemmas. Both are real dangers. However, if decisions are informed by a solid understanding of the precise nature of the patient's substance use as outlined above, the chances of such bad outcomes are lessened.
That said, the fear of over-prescribing should not prevent effective pain management. Surgical teaching on treatment of appendicitis holds that:
Accuracy of preoperative diagnosis should be about 85%. If it is considerably less, some unnecessary operations are probably being done, and a more rigorous pre-operative differential diagnosis is in order. On the other hand, an accuracy consistently greater than 90 percent should also cause concern, since this may mean that some patients with atypical but bona fide acute appendicitis are being "observed" when they should have prompt surgical intervention.13
A similar line of thought might well be applied to the use of controlled pain medications. It is better to tolerate a degree of manipulation and drug-seeking behavior in a population of patients than to allow a high prevalence of un- or undertreated pain. This is especially true in the case of the patients who are the concern of this book -- those living with HIV/AIDS who need palliation and end-of-life care.
Symptoms other than pain are managed much the same in the substance-using population as in other groups. It should be remembered, however, that pain (physical, psychic or spiritual) can and will exacerbate suffering associated with a variety of symptoms. If, therefore, pain is not appropriately managed in the substance user, it is less likely that other symptoms will resolve either.