Combination Pain Therapy in HIV Neuropathy

Peripheral neuropathy is now recognized as the most common neurological complication of HIV disease and its treatment. Before highly active antiretroviral therapy (HAART) was introduced, the prevalence of HIV-associated distal sensory polyneuropathy (DSP) was already estimated to be 35%, mostly contained to populations with moderate to advanced immunosuppression. Now, since the advent of HAART, the prevalence of HIV-associated neuropathy has increased to 52%, possibly due to a combination of antiretroviral toxic neuropathy (ATN), decreased mortality, and accumulated medical comorbidities. Successful treatment of neuropathic pain is inherently difficult, and treatment of HIV-associated neuropathic pain is particularly complicated. To date, evidence supporting effective therapies for neuropathic HIV-associated pain is lacking, despite several types and classes of drugs having been evaluated in clinical trials. This study will evaluate the safety and efficacy of duloxetine, methadone, and the combination of duloxetine and methadone in painful HIV-associated neuropathy. Both of these drugs are approved by the Food and Drug Administration (FDA) but for purposes unrelated to HIV-associated neuropathy, and no previous studies have utilized these two treatments for this purpose. For this study, 120 participants with painful HIV-associated neuropathy will be recruited. The trial will last for approximately 23 weeks. Each participant will receive a total of 4 study treatments. The following treatment pairings will be given in a sequence determined by randomization: 1. duloxetine and methadone placebo 2. methadone and duloxetine placebo 3. duloxetine and methadone 4. duloxetine placebo and methadone placebo Each treatment period will last 4 weeks and will be followed by a 1-week combined taper and washout. People wishing to enroll in this study will have a screening visit that will last about 3 hours. During this visit, participants will have an HIV test, physical exam, neurologic exam, blood drawn, electrocardiogram (EKG), and a pregnancy test, if applicable. Participants will also be asked about their current health and any medications they may be taking. They will also be asked about their mood and be given the results of tests performed at the screening visit. If screening qualifies participants for the study, they will return for a pre-entry visit lasting 2 hours. During this visit, participants will have a limited physical exam and be asked about changes in their health or medicines since screening. Participants will also be given a pain diary with instructions to record neuropathy pain every day for each of the 7 days before beginning the study and throughout the study. After beginning the study, participants will return to the clinic for another 8 visits. These visits are at the end of each 4-week treatment period and at the end of each 1-week crossover period. At each visit, there will be a limited physical exam and participants will answer questions about their health and medications. Participants will also be told the results of routine lab tests and pregnancy tests performed during the study.