Three new 19-nortestosterone progestogens, which are chemically related to levonorgestrel, are now clinically available in combination oral contraceptives in Europe. Desogestrel and norgestimate must be transformed to metabolites for all or part of their biologic activity; gestodene is active in its original form. Compared with present low-dose monophasic and triphasic levonorgestrel formulations, the new combinations appear to be equivalent in efficacy and type and frequency of side effects. Cycle control may be slightly improved with the gestodene preparation and somewhat poorer with the desogestrel regimen. As with the present triphasics, most changes reported in coagulation indexes for the new combinations remained within normal limits, as did changes in carbohydrate and lipid metabolism. There is no present evidence that either the norgestimate or aesogestrel formulation provides a clinical improvement over the levonorgestrel triphasic. In the gestodene combination, the progestogen's increased biologic activity allows further reduction of total steroid dose.
PIP: 3 new progestogens are now available in combination oral contraceptives (OCs) in Europe: desogestrel, gestodene, and norgestimate. All are 19-nortestosterone derivatives that are chemically and biologically related to levonorgestrel. Desogestrel and norgestimate must be transformed to metabolites for all or part of their biologic activity, while gestodene is active in its original form and can be administered in the lowest dose. Numerous studies have been carried out to determine whether these new progestogen compounds provide a clinical advantage over compounds presently available in the US such as Nordette and Triphasil. The new regimens appear to be equivalent in efficacy (use effectiveness rate of less than 1 pregnancy/100 woman-years) to current low-dose monophasic and triphasic combinations. Compared with levonorgestrel monophasic OC data, the gestodene compound appears to offer slightly better menstrual cycle control and the desogestrel compound somewhat less control. The type and frequency of side effects seem to be the same as those commonly seen with low-dose monophasic and triphasic OCs. As with the present triphasics, most changes in coagulation indexes for the new combinations remain within normal limits, as do changes in carbohydrate and lipid metabolism. Overall, there is as yet no evidence that either the norgestimate or the desogestrel formulation offers any significant improvements over the levonorgestrel triphasic. On the other hand, gestodene has the advantage of allowing a further reduction of the total steroid dose.