Ethinylestradiol + norelgestromin: new preparation. Transdermal contraception: no tangible progress

Abstract

(1) The reference hormone-based contraceptive for women is an oral contraceptive combining ethinylestradiol (about 30 micrograms) and a well-known progestin such as levonorgestrel or norethisterone. (2) A transdermal contraceptive patch delivering 20 micrograms of ethinylestradiol and 150 micrograms of norelgestromin over 24 hours, and designed to be left in place for a whole week, three weeks a month, has recently been marketed in France. (3) Norelgestromin is the active metabolite of norgestimate, which is already available in combined contraceptives but is less well evaluated than some other progestins. Norelgestromin is metabolised by the liver, notably into norgestrel. (4) The clinical evaluation dossier of the new transdermal contraceptive contains data from two comparative unblinded trials, one versus a triphasic combination of oral ethinylestradiol + levonorgestrel, and the other versus oral ethinyl estradiol (20 micrograms) + desogestrel. A third, non comparative trial offers weaker evidence. These three trials included about 3300 women in total, and lasted between 6 and 13 cycles. The patch was about as effective as the comparator contraceptives. (5) In the three main clinical trials, 4.7% of patches had to be replaced because they became unstuck, either completely (1.8%) or partially (2.9%). (6) More women dropped out of the groups using patches (19.9% of the patch group compared with 14.5% of the group taking oral contraceptives in one trial, 29.6% versus 24.3% in the other trial). Women using the patch were more likely than other women to stop their treatment because of adverse events (about 12% versus 5%). (7) Breast discomfort, breast tenderness or pain were reported by 22% of women using the patches and by 9% and 6% of women in the two comparator groups. Women using the patches had slightly longer menstrual periods (5.6 days versus 4.7 days). Reactions at the patch site were reported by 17% of women. (8) There is no evidence that the patch is any less likely than reference oral contraceptives to cause thromboembolism. The true thromboembolic risk associated with the new patches is unknown. (9) Used patches still contain large amounts of active substances, and must be placed in sachets (provided in the packet) and taken to a pharmacy for disposal. (10) In practice, the reference combined contraceptive for women is still oral ethinylestradiol (about 30 micrograms) plus a well-known progestin such as levonorgestrel or norethisterone. Ethinylestradiol + norelgestromin patches offer women no real benefits: they are probably less convenient and may be less safe.