A Review of Transdermal Hormonal Contraception

Imperfect use of contraceptive methods notably increases the likelihood of pregnancy. One means of improving user adherence with hormonal contraception is to minimize the dosing schedule. Two forms of hormonal contraceptive have currently achieved this goal: the transdermal patch and the vaginal ring. The first and only transdermal contraceptive patch to receive worldwide regulatory approval (ethinylestradiol/norelgestromin) is a convenient approach to contraception that has a similar efficacy to oral contraceptives (OCs), but with the benefit of once-weekly administration. In addition, transdermal delivery of contraceptive hormones eliminates variability in gastrointestinal absorption, avoids hepatic first-pass metabolism, and prevents the peaks and troughs in serum concentrations that are seen with OCs. Norelgestromin, the progestin contained in the patch, is the active metabolite of norgestimate and is structurally related to 19-nortestosterone. Norgestimate and norelgestromin mimic the physiologic effects of progesterone at the progesterone receptor; however, norelgestromin has negligible direct or indirect androgenic activity, suggesting that it may be suitable for women with disorders related to androgen excess (such as hirsutism, acne, and lipid disorders). Contraceptive effectiveness is usually a function of the efficacy of a contraceptive in combination with compliance with its dosing regimen. The efficacy of the contraceptive patch has been clearly demonstrated in three phase III trials, two of which were randomized comparisons with an OC. The likelihood of pregnancy was similar between these contraceptive methods; however, compliance with the patch was notably better, particularly in younger women. The safety and tolerability profile of the patch was similar to that of the OC. A cost-effectiveness analysis has suggested that the contraceptive patch is more cost effective than the OC, due to decreased costs related to unwanted pregnancy.