ABSTRACT
Etravirine (ETR) belongs to the family of non-nucleoside analogue reverse transcriptase inhibitors (NNRTIs), with antiviral activity in patients with resistance to first-generation NNRTIs. The drug interactions caused by ETR are due to its dual effect on the CYP450 system. ETR acts as an inducer of CYP3A4 and inhibitor of CYP2C9 and CYP2C19. This drug shows few clinically significant drug interactions, the most important of which involve the unboosted protease inhibitors, the NNRTIs efavirenz and nevirapine, full-dose ritonavir and tipranavir/ritonavir. Interaction with fosamprenavir/ritonavir is not clinically significant, although their plasma levels vary slightly when used in combination with ETR. ETR shows no interactions with darunavir/ritonavir.
