The pharmacokinetics of buprenorphine and its metabolites were detemined in opioid-dependent, buprenorphine-naloxone-maintained, HIV-negative volunteers (n=10) before and after 15 days of fosamprenavir/ritonavir (1400/200 mg once daily) administration.  Amprenavir pharmacokinetics and adverse effects were compared between the buprenorphine-maintained participants and a control group of non-opioid-dependent subjects who received fosamprenavir/ritonavir (1400/200 mg once daily) alone.  Fosamprenavir-ritonavir did not significantly affect the pharmacokinetics of buprenorphine or norbuprenorphine, but did significantly increase the AUC of the inactive buprenorphine-3-glucuronide. No buprenorphine related side effects or withdrawal symptoms were observed.  Buprenorphine-naloxone had no significant effects on the pharmacokinetics of amprenavir with concentrations remaining within the therapeutic range during buprenorphine-naloxone treatment. Dose adjustments are not likely to be necessary when buprenorphine and fosamprenavir/ritonavir are coadministered.
Interactions between buprenorphine and the protease inhibitors darunavir-ritonavir and fosamprenavir-ritonavir. Gruber VA, Rainey PM, Moody DE, et al. Clin Infect Dis, 2012, 54(3): 414-23.