Lack of an effect of atazanavir on steady-state pharmacokinetics of methadone in patients chronically treated for opiate addiction.

Background: Effective antiretroviral treatment of opiate-addicted drug users with HIV infection often requires concomitant substance abuse treatment, commonly with methadone. Pharmacological interactions between antiretroviral drugs and methadone may result in opiate withdrawal or increased side effects.

Objectives: To determine if atazanavir, a once-daily protease inhibitor and moderate inhibitor of P450 CYP3A4, exhibited pharmacokinetic interactions with (R)-methadone.