Efavirenz, in contrast to nevirapine, is associated with unfavorable progesterone and antiretroviral levels when coadministered with combined oral contraceptives.

Landolt NK, Phanuphak N, Ubolyam S, Pinyakorn S, Kriengsinyot R, Ahluwalia J, Thongpaeng P, Gorowara M, Thammajaruk N, Chaithongwongwatthana S, Lange JM, Ananworanich J.

J Acquir Immune Defic Syndr. 2013 Apr 15;62(5):534-9. doi: 10.1097/QAI.0b013e31827e8f98.

BACKGROUND: Effective contraception has been widely promoted for HIV-positive women. However, there are limited data on the interactions between combined hormonal contraceptives and nonnucleoside reverse transcriptase inhibitors . METHODS: This study assessed the steady-state contraceptive effectiveness and safety of combined oral contraceptive (COC) containing 0.150 mg desogestrel /0.030 mg ethinyl estradiol with either nevirapine (NVP) or efavirenz (EFV) in 34 HIV-positive women. The targeted level for contraceptive effectiveness was endogenous progesterone level < 3.0 ng/mL. We measured NVP/EFV plasma concentrations 12 hours after administration (C12) with and without COC. The desired therapeutic levels were >3.1 mg/L for NVP and 1.0-4.0 mg/L for EFV, respectively. RESULTS: All 18 subjects in the NVP group had serum progesterone <1.0 ng/mL. Four of 16 subjects (25%) in the EFV group had serum progesterone >1.0 ng/mL, including 3 subjects with >3.0 ng/mL (might indicate ovulation). The difference in progesterone levels between the 2 groups was statistically significant (P = 0.04). The median C12 of NVP increased insignificantly by 17% with COC; the median C12 of EFV decreased significantly (P = 0.02) by 22%. In 3 of 16 subjects (19%) in the EFV group, C12 of EFV dropped below 1.0 mg/L. CONCLUSIONS: In contrast to NVP, coadministrating desogestrel/ethinyl estradiol containing COC with EFV was associated with unfavorable progesterone and antiretroviral levels. Our results suggest that NVP may be superior to EFV when used with COC in HIV-positive women.

PMID: 23187949

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.