Pharmacokinetics of the contraceptive steroids levonorgestrel and gestodene after single and multiple oral administration to women
Article Abstract:
Oral contraceptives contain derivatives of two female reproductive steroid hormones, estrogen and progesterone. Ethinyl estradiol (EE2) is commonly used to provide the estrogen, while levonorgestrel (LNG) and gestodene (GEST) can provide the progesterone component. LNG has been available for many years, while GEST has only recently been available, and accordingly, the pharmacokinetics of LNG is better studied than that of GEST. Frequently, the effects of only single doses of these compounds have been studied, rather than the consequences of treatment through an entire monthly cycle. The pharmacokinetics of either single doses or full-cycle treatment with oral contraceptives containing EE2 and LNG or GEST was evaluated in a study of 15 Japanese women and 10 white women. Levels of LNG and GEST were very similar during treatment cycles. Blood levels of LNG became steady after 16 days of treatment. LNG levels following full-cycle treatment were about three times higher than anticipated from calculations from single-dose studies, and similar findings for GEST were observed. This was related to single-dose calculations not taking into account any changes in liver metabolism and levels of steroid-transporting proteins that follow treatment with contraceptive steroids. The study indicates that while single-dose studies can not entirely predict the pharmacokinetic behavior of LNG or GEST, computer modeling that takes into account EE2-related changes in steroid-transporting protein can provide an estimate of trends in blood concentrations of these progesterone-related drugs. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1990
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Metabolic and endocrine effects of the desogestrel-containing oral contraceptive Mircette
Article Abstract:
The oral contraceptive Mircette appears to have few serious metabolic side effects. Mircette is a new oral contraceptive containing low levels of estrogen and desogestrel. Blood levels of various chemicals including cholesterol, blood sugar and insulin were measured in women taking Mircette. The drug had a favorable effect on cholesterol levels because it raised high-density lipoprotein, or 'good' cholesterol levels and did not substantially raise low-density lipoprotein, or 'bad' cholesterol levels. The drug did not substantially affect blood sugar or insulin levels.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1998
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