Atazanavir, with or without ritonavir, may increase buprenorphine and buprenorphine metabolites, requiring dose adjustment

This study examined the interaction between buprenorphine and atazanavir (400 mg once daily) or atazanavir/ritonavir (300/100 mg once daily) in opioid-dependent, buprenorphine/naloxone-maintained, HIV-negative volunteers. Pharmacokinetics of atazanavir and atazanavir/ritonavir were compared in subjects and matched, healthy controls (n=10 per group) to determine effects of buprenorphine. Objective opiate withdrawal scale scores and mini-mental state examination were determined prior to and following antiretroviral administration to examine pharmacodynamic effects.

When coadministered with atazanavir, buprenorphine AUC increased from 39.5 to 76.3 ng.h/ml; a similar increase was observed when coadministered with atazanavir/ritonavir (46.2 to 77.0 ng.h/ml). Concentrations of norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide also increased with both atazanavir and atazanavir/ritonavir. The likely complex mechanism is discussed. Buprenorphine did not significantly alter atazanavir or ritonavir concentrations. Three buprenorphine/naloxone-maintained participants reported increased sedation with atazanavir/ritonavir.

Atazanavir or atazanavir/ritonavir may increase buprenorphine and buprenorphine metabolite concentrations and might require a decreased buprenorphine dose.

McCance-Katz EF, Moody DE, Morse GD et al. Interaction between buprenorphine and atazanavir or atazanavir/ritonavir. Drug Alcohol Depend, 2007, 91(2-3): 269-278.