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 17β-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.
Copyright © 2013 Elsevier Inc. All rights reserved.
MeSH terms
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Contraceptives, Oral, Combined / administration & dosage
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Contraceptives, Oral, Combined / adverse effects
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Contraceptives, Oral, Combined / pharmacokinetics*
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Contraceptives, Oral, Combined / pharmacology
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Dose-Response Relationship, Drug
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Drug Interactions
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Estradiol / administration & dosage
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Estradiol / adverse effects
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Estradiol / analogs & derivatives
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Estradiol / biosynthesis
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Estradiol / pharmacokinetics*
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Estradiol / pharmacology
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Estrogens / administration & dosage
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Estrogens / adverse effects
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Estrogens / pharmacokinetics
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Estrogens / pharmacology
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Ethinyl Estradiol / administration & dosage
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Ethinyl Estradiol / adverse effects
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Ethinyl Estradiol / pharmacokinetics*
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Ethinyl Estradiol / pharmacology
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Female
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Humans
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Menstrual Cycle / drug effects
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Menstrual Cycle / metabolism
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Progesterone / metabolism
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Progestins / administration & dosage
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Progestins / adverse effects
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Progestins / pharmacokinetics
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Progestins / pharmacology
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Risk Assessment
Substances
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Contraceptives, Oral, Combined
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Estrogens
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Progestins
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Ethinyl Estradiol
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Progesterone
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Estradiol