Protease Inhibitors and Combined Oral Contraceptive Pharmacokinetics and Pharmacodynamics

Summary

The project is a two-arm prospective cohort and pharmacokinetic study comparing levonorgestrel and ethinyl estradiol pharmacokinetics in HIV-positive women taking antiretroviral regimens that include ritonavir to those in women who take regimens known not to interact with combined oral contraceptives. In addition, the prevalence of ovulation will be measured in each group. Participants will take a combined oral contraceptive containing levonorgestrel and ethinyl estradiol for 21 days, during which they will undergo twice-weekly serum progesterones. On the final day, they will complete a pharmacokinetic study. The investigators hypothesize that levonorgestrel levels, as measured by area-under-the-curve from 0 to 72 hours, will be increased in women on ritonavir, while ethinyl estradiol levels will be decreased and ovulation, defined by a serum progesterone of at least 3 ng/mL, will be unchanged. This study will be the first to evaluate the effects of ritonavir on the pharmacokinetics of a combined oral contraceptive containing the progestin levonorgestrel. In addition, no previous studies have rigorously assessed ovulation in women taking protease inhibitors and combined oral contraceptives. As a result, this study will provide new information correlating pharmacokinetic changes with effects on ovulation.

Timeline

Start

2015-08

Primary completion

2016-11

Completion

2016-11-01

Drugs

Indications