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Pharmacokinetic Interaction Between Nevirapine and Ethinyl Estradiol/Norethindrone When Administered Concurrently to HIV-Infected Women

Mildvan Donna; Yarrish, Robert; Marshak, Ann; Hutman, Herbert W.; McDonough, Marita; Lamson, Michael; Robinson, Patrick
JAIDS Journal of Acquired Immune Deficiency Syndromes: April 15th, 2002
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Objective:To determine the effects of nevirapine (NVP), a nonnucleoside reversetranscriptase 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. On day 30, intensive PK sampling was performed after concurrent administration of NVP 200 mg and a single dose of EE/NET.

Results:Concomitant administration of NVP at steady state with EE/NET resulted in a significant (29%) median reduction in the area under the plasma concentration time curve (AUC∞) and a significant reduction in mean residence time (MRT) and half-life (t1/2) of EE. There was a significant (18%) median reduction in the AUC∞ for NET that was not associated with a detectable change in NET Cmax, MRT, or t1/2.

Conclusion:Oral contraceptives should not be the primary method of birth control in women of child-bearing potential who are treated with NVP.

Address correspondence and reprint requests to Donna Mildvan, Beth Israel Medical Center, Division of Infectious Diseases, First Avenue at 16th Street, New York, NY 10003; e-mail:mildvan@ix.netcom.com

Manuscript received August 31, 2001; accepted January 25, 2002.

© 2002 by Lippincott Williams & Wilkins