The Clinical Guide to Supportive and Palliative Care for HIV/AIDS

A Clinical Guide to Supportive and Palliative Care for HIV/AIDS • Chapter 11: Substance Use ProblemsThe concept of dependence is important in that the symptoms of drug withdrawal (which mayinclude malaise, musculoskeletal pain, and abdominal pain) may need to be distinguished fromthe underlying pain disorder in patients who become opioid-dependent and may require additional26interventionpicas(e.g., use of longer-acting drugs) to ensure a steady-state over the 24-hourdosing period.When switching between opioids and analgesics clinicians must be familiar with conversionsbetween 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, theinitial dose of a new opioid should be about half of the calculated dose and the patient observedfor side effects. Rapid scale-up of the medication can follow.Meperidine (which has long-acting metabolites) and mixed agonist-antagonist agents thatcan precipitate withdrawal such as pentazocine and butorphanol should generally be avoided.Providers should also be careful when prescribing narcotic combinations that include potentiallyhepatotoxic agents like acetaminophen (e.g., fixed-combination oxycodone or codeineplus 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 alreadyat 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 thoseknown 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 patientswhose substance use is in remission may strongly object to administration of any drug using aneedle 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 orhousehold members), long-acting, transdermal, and generic formulations are best, even thoughmisuse can still occur with all of these options. Indwelling catheters pose particular problems inthat they can be, and are, misused by some patients. In these cases, a percutaneous infusionpump 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. Thereare no easy answers to these dilemmas. Both are real dangers. However, if decisions are informedby a solid understanding of the precise nature of the patient’s substance use as outlinedabove, the chances of such bad outcomes are lessened.That said, the fear of over-prescribing should not prevent effective pain management. Surgicalteaching on treatment of appendicitis holds that:Accuracy of preoperative diagnosis should be about 85%. If it isconsiderably less, some unnecessary operations are probably beingdone, and a more rigorous pre-operative differential diagnosis is inorder. On the other hand, an accuracy consistently greater than 90percent should also cause concern, since this may mean that somepatients with atypical but bona fide acute appendicitis are being“observed” when they should have prompt surgical intervention. 13262U.S. Department of Health and Human Services • Health Resources and Services Administration • HIV/AIDS Bureau