fosamprenavir + ritonavir + methadone

Fosamprenavir is a prodrug of amprenavir and acts as an HIV-1 protease inhibitor. It is used in combination with other antiretroviral agents for the treatment of human immunodeficiency virus (HIV-1) infection. Ritonavir is also an HIV-1 protease inhibitor but is primarily used at low doses to boost the plasma levels of other protease inhibitors by inhibiting cytochrome P450 3A4 (CYP3A4). Methadone is a synthetic opioid agonist used for pain management and as maintenance therapy in opioid dependence. When co-administered, both fosamprenavir/ritonavir can decrease plasma concentrations of methadone due to induction or modulation of CYP3A-mediated metabolism and possibly increased clearance via other pathways. This interaction may lead to symptoms of opiate withdrawal in patients maintained on methadone[6][1][8]. The combination regimen's primary indication remains HIV-1 infection; however, careful monitoring for drug-drug interactions with methadone is required.

Other names

amprenavir prodrug (for fosamprenavir)