Print this page    •   Back to Web version of article

Quad Reduces Levels of Oral Contraceptives

May/June 2011

This open-label fixed-sequence study investigated the pharmacokinetics of a combined oral contraceptive containing 25 µg ethinylestradiol and norgestimate with a fixed dose combination tablet containing elvitegravir, cobicistat, FTC and TDF ("Quad").


Steady-concentrations of ethinylestradiol, norelgestromin (the active metabolite of norgestimate), EVG and cobicistat were determined in 15 HIV-negative women receiving the oral contraceptive alone or with the "quad" tablet. Coadministration decreased the AUC of ethinylestradiol by #&126;25% and increased the AUC of norelgestromin by #&126;2-fold. Concentrations of elvitegravir and cobicistat were within the range of values observed in previous studies. Changes in progesterone and FSH were similar in both treatment phases, but changes in LH were greater in the combination phase.

In light of the decrease in ethinylestradiol, it is recommended that when coadministered with the "Quad" tablet, oral contraceptives should contain at least 30 µg ethinylestradiol.


  1. German P et al. EVG/cobicistat/FTC/TDF and oral contraceptives Pharmacokinetic interaction between norgestimate/ethinyl estradiol and EVG/COBI/FTC/TDF single tablet regimen. Oral abstract: O_17.

Provided by

This article was provided by HIV i-Base. It is a part of the publication HIV Treatment Bulletin. You can find this article online by typing this address into your Web browser:

General Disclaimer: is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, consult your health care provider.