Pharmacokinetic interaction between nevirapine and ethinyl estradiol/norethindrone when administered concurrently to HIV-infected women.

Objective: To determine the effects of nevirapine (NVP), a nonnucleoside reverse-transcriptase inhibitor of HIV-1 and P450 inducer, on the pharmacokinetics (PK) of ethinyl estradiol (EE)/norethindrone (NET), a widely used oral contraceptive, and to assess the effects of EE/NET on the steady-state PK of NVP.

Methods: Ten HIV-1-infected women underwent intensive PK sampling after single-dose administration of EE/NET (days 0-1). Oral NVP 200 mg once daily (days 2-15), followed by 200 mg twice daily (days 16-29), was added to background potent antiretroviral therapy.