New progestins--clinical experiences: gestodene

Gestodene, one of three new gonane progestins, is the most potent on a per weight basis in regard to progestational effects and has little or no estrogenic effect. In in vivo animal studies, gestodene also has less androgenic activity compared with progestins found in older combination oral contraceptive formulations. It binds to mineralocorticoid receptors and consequently is a competitive aldosterone inhibitor, leading to speculation that it may be beneficial in hypertensive patients. Numerous large clinical trials have shown that the combination of gestodene and ethinyl estradiol is as effective in preventing pregnancies as other oral contraceptives presently on the market. Irregular bleeding and spotting rates appear to be at least as good as older formulations. In general, studies show that the incidence of side effects associated with the progestin and estrogen components tends to be low, with very little impact on lipid and carbohydrate metabolism. Gestodene-containing oral contraceptives have been associated with small increases in clotting factors, generally because of the estrogen component, with compensatory changes in the fibrinolytic system. Although gestodene-containing oral contraceptives have been used in Europe since 1987, they have not been available in the United States except for use in clinical trials. At present, a triphasic formulation containing 50 to 100 micrograms of gestodene plus 30 to 40 micrograms of ethinyl estradiol is awaiting approval by the Food and Drug Administration.