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

A Clinical Guide to Supportive and Palliative Care for HIV/AIDS • Chapter 4: PainCorticosteroidsCorticosteroid drugs have analgesic potential in a variety of chronic pain syndromes, includingneuropathic26 picaspains and pain syndromes resulting from inflammatory processes. 111 Like other adjuvantanalgesics, corticosteroids are usually added to an opioid regimen. In patients with advanceddisease, these drugs may also improve appetite, decrease nausea and malaise, and improve the overallquality of life. Adverse effects include neuropsychiatric syndromes, gastrointestinal disturbancesand immunosuppression.BaclofenBaclofen is a GABA-agonist that has proven efficacy in the treatment of trigeminal neuralgia. 122 Onthis basis, a trial of this drug is commonly employed in the management of paroxysmal neuropathicpains of any type. Dosing is generally undertaken in a manner similar to the use of the drug for itsprimary indication, spasticity. A starting dose of 5 mg two to three times per day is gradually escalatedto 30-90 mg per day, and sometimes higher if side effects do not occur. The most common adverseeffects are sedation and confusion.Oral Local AnestheticsLocal anesthetic drugs may be useful in the management of neuropathic pains characterized byeither continuous or lancinating dysesthesias. Controlled trials have demonstrated the efficacy oftocainide and mexiletine and clinical evidence suggests similar effects from flecainide and subcutaneouslidocaine. 123, 124, 125, 126 It is reasonable to undertake a trial with oral local anesthetic inpatients with continuous dysesthesias who fail to respond adequately to, or who cannot tolerate, thetricyclic antidepressants, and with patients with lancinating pains refractory to trials of anticonvulsantdrugs and baclofen.Mexiletine is preferred in the U.S. 111 Paice and colleagues in 2000 studied twenty-six subjects inorder to test the efficacy of topical capsaicin in the management of HIV-associated pain. 127 Resultssuggest that capsaicin was ineffective in relieving pain with HIV-associated distal symmetrical peripheralneuropathy (DSPN). However capsaicin has been shown to be effective in relieving painassociated with other neuropathic pain syndromes. 127Drug Interactions: Analgesics and Anti-HIV Drug TherapiesMany of the available anti-HIV drugs have the potential to interact with other medications prescribedfor pain, depression, anxiety or other medical conditions. These drug interactions can bedangerous, resulting in drug toxicities due to elevated levels of medication, or drug ineffectivenessdue to lower drug levels in the serum. Opioid analgesics can interact with certain anti-HIV drugtherapies and these interactions should be kept in mind when prescribing opioids.The protease inhibitor ritonavir (Norvir) can increase the levels of several opioid drugs includingcodeine, hydrocodone, oxycodone, methadone, and fentanyl. Patients on ritonavir should not beprescribed meperidine or propoxyphene because of increased risk of serious toxicity. Antidepressantand anticonvulsant analgesics can also interact primarily with ritonavir. Ritonavir can increase theserum levels of bupropion (Wellbutrin, Zyban), fluoxetine, trazodone, and desipramine, resulting inincreased drug toxicities (e.g., seizures with bupropion). Both ritonavir and saquinavir (Invirase)may increase levels of anticonvulsants such as phenobarbital, phenytoin, carbamazepine andclonazepam.114U.S. Department of Health and Human Services • Health Resources and Services Administration • HIV/AIDS Bureau