Cited by 100Reproductive Health and ContraceptionEstrogen and related hormone effectsEffects and risks of endocrine disrupting chemicals

Formation of Ethinyl Estradiol in Women during Treatment with Norethindrone Acetate

Chu, Micheline C., Zhang, Xiaohua, Gentzschein, Elisabet, Stanczyk, Frank Z., Lobo, Rogerio A.·2007·The Journal of Clinical Endocrinology & Metabolism

Abstract

CONTEXT: The significance of the conversion of norethindrone acetate (NET-A), a commonly prescribed, synthetic, oral progestogen, to ethinyl estradiol (EE(2)) is controversial. OBJECTIVE: We sought to determine accurately the extent to which NET-A may be converted to EE(2), and if so, whether circulating levels of EE(2) would be of clinical significance. DESIGN, SUBJECTS, AND INTERVENTIONS: We administered NET-A 10, 20, or 40 mg once daily for 7 d to 20 regularly menstruating premenopausal women and measured NET-A and EE(2) levels before drug intake; at 1, 2, 4, 8, and 24 h after the first dose; and 2 h after the seventh dose. RESULTS: The mean EE(2) maximum serum concentration obtained from the 10-, 20-, and 40-mg doses of NET-A in this study is 58, 178, and 231 pg/ml, respectively. The conversion ratio of NET-A to EE(2) ranged from 0.20 to 0.33% for the different doses. CONCLUSIONS: NET-A is converted to EE(2), and although the conversion rate is relatively small, higher doses of NET-A, as used clinically, give rise to substantial levels of EE(2).

Integrity signals

Registry

Crossref · 10.1210/jc.2007-0044

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Authors
Chu, M. C., Zhang, X., Gentzschein, E., Stanczyk, F. Z., & Lobo, R. A.
Affiliations
  • Columbia University (US)
  • University of Southern California (US)
Venue
The Journal of Clinical Endocrinology & Metabolism
Published
2007-06
Volume
92
Issue
6
Pages
2205-2207
ISSN
  • 0021-972X (ISSN-L)
  • 1945-7197
OpenAlex
W2054703956
Cited by
100
References
9
Citations by year
2026: 5 · 2025: 7 · 2024: 7 · 2023: 8 · 2022: 10 · 2021: 6 · 2020: 8 · 2019: 3 · 2018: 6 · 2017: 4 · 2016: 5 · 2015: 6 · 2014: 1 · 2013: 2 · 2012: 6
FWCI
3.78
Type
journal article
Language
en
Open access
closed
Locations
  • The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Reproductive Health and Contraception
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Estrogen and related hormone effects
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Effects and risks of endocrine disrupting chemicals
Keywords
norethindrone acetate, ethinyl estradiol, oral contraceptives, premenopausal women, serum estradiol levels
MeSH terms
Norethindrone Acetate, Adult, Contraceptives, Oral, Synthetic, Ethinyl Estradiol, Female, Humans, Norethindrone, Premenopause, Area Under Curve

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