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Review article| Volume 87, ISSUE 6, P706-727, June 2013

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Ethinyl estradiol and 17��-estradiol in combined oral contraceptives: pharmacokinetics, pharmacodynamics and risk assessment

  • Frank Z. Stanczyk
    Correspondence
    Corresponding author. USC Keck School of Medicine, Reproductive Research Laboratory, Livingston Research Building, 1321 North Mission Road, Los Angeles, CA 90033, USA. Tel.: +1 323 226 3220; fax: +1 323 226 2850.
    Affiliations
    Departments of Obstetrics and Gynecology and Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
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  • David F. Archer
    Affiliations
    Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA 23507, USA
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  • Bhagu R. Bhavnani
    Affiliations
    Department of Obstetrics and Gynecology, University of Toronto, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada
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      Abstract

      The need to seek improved combined oral contraceptive (COC) efficacy, with fewer health risks and better acceptability, has been ongoing since the introduction of COCs more than 50 years ago. New progestin formulations combined with lower doses of ethinyl estradiol (EE), the predominant estrogenic component of COCs, have reduced the incidence of venous thromboembolism and other negative outcomes of COC treatment. Previous attempts to use endogenous 17��-estradiol (E2) instead of EE were limited primarily by poor cycle control. The recent introduction of E2-based formulations has renewed interest to determine if there are potential benefits of using E2 in COCs. These formulations have been shown to have similar efficacy and cycle control as EE-based COCs. This review provides a brief summary of the pharmacology of EE and E2, including metabolism, pharmacokinetics and pharmacodynamics, as well as adverse effects of these estrogens.

      Keywords

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