CYP2B6

Cytochrome P450 enzyme that metabolises efavirenz, bupropion, methadone and cyclophosphamide.

CYP2B6 induction (e.g. rifampicin, phenobarbital) lowers efavirenz and bupropion concentrations; inhibition increases exposure.

Relevant in antiretroviral therapy: rifampicin markedly lowers efavirenz concentrations.