Interaction between fosamprenavir, with and without ritonavir, and nevirapine in human immunodeficiency virus-infected subjects.

Fosamprenavir (FPV) with and without ritonavir (RTV) was added to the antiretroviral regimens of human immunodeficiency virus-infected subjects receiving nevirapine (NVP) to evaluate this drug interaction. Significant reductions in plasma amprenavir exposure (25 to 35%) were observed following coadministration of 1,400 mg of FPV twice a day (BID) and 200 mg of NVP BID. A regimen of 700 mg of FPV BID plus 100 mg of RTV BID may be coadministered with NVP without dose adjustment.