[New gestagens--advantages and disadvantages]

Due to their high oral bioavailability synthetic progestagens are used for therapy, hormone replacement therapy and contraception There are different types of progestogens. There are progesterone derivatives, nortestosterone derivatives (13-methyl-gonanes and 13-ethyl-gonanes), spirolactone derivatives and norpregnance derivatives which differ in their efficacy and hormonal profile. All progestagens show antiestrogenic activities, inhibit the estrogen-induced proliferation of the endometrium and, hence, decrease the risk of endometrial hyperplasia. With the exception of Dienogest, the derivatives of 19-nortestosterone are characterized by a 17-alpha-ethynyl group and show slight androgenic properties which may antagonise some estrogen-dependent alterations of hepatic serum parameters. Tibolone which is a derivative of norethynodel also belongs to this group. Among the nortestosterone derivatives, there are the so-called "Prodrugs". Prodrugs are rapidly transformed after intake to the active progestagens. Progesterone derivatives partly exert moderate androgenic or antiandrogenic effects, while the spirolactone derivative Drospirenone shows antimineralocorticoid and antiandrogenic activities. The progesterone derivatives as well as Gestodene and Desogestrel have certain glucocorticoid activities which, at the doses used, are not clinically relevant, but possibly may influence vascular function. The effects of 19-norpregnane derivatives are comparable with those of progesterone derivatives. According to their different hormonal profiles and activities, the various available progestogens allow the choice of preparations which are best suitable for the individual woman for contraception or hormone replacement therapy.