|December 2002 · Vol. 14, No. 12
Transdermal contraception: update on clinical management
With efficacy rates at least as high as those of the pill, and even greater patient compliance, the patch significantly broadens the contraceptive armamentarium.
Dr. Zieman is associate professor and director of family planning, department of OBG, Emory University School of Medicine, Atlanta, Ga.
The transdermal contraceptive system is a combination hormonal patch that contains 6 mg norelgestromin and 0.75 mg ethinyl estradiol (EE2) in a stable adhesive, and delivers a daily dose of 150 μg norelgestromin and 20 μg EE2to the bloodstream.
Three large contraceptive trials, in which 3,319 women used the contraceptive patch worldwide, reported low pregnancy rates, with an overall Pearl index of 0.88.
The primary goals of management are increasing correct and consistent use and effectively counseling and educating women about adverse effects, thereby enhancing continuation rates.
In studies involving more than 70,000 patches, only 4.7% were replaced because of partial or complete detachment. In 1 health-club study, with physical exertion and variable temperature and humidity, only 1 of 87 patches became completely detached.
Treatment-limiting events were reported in 1% to 2.4% of women in clinical trials and included nausea and/or vomiting, application-site reaction, breast symptoms, headache, and emotional lability.
The delivery of hormones via a transdermal patch is not a new development. Estrogen and estrogen-progestin transdermal systems have been used for a number of years to treat the symptoms of menopause.1-3 However, until now, no patch-delivery system was able to administer sufficient hormones to prevent pregnancy.
Transdermal delivery systems are warranted for drugs that are highly potent and lipophilic.4 Published studies demonstrate some patient preference for transdermal systems over oral dosing, particularly drug-in-adhesive transdermal systems (as opposed to first-generation reservoir systems).5,6 In 1 study, drug-in-adhesive systems were rated as having better cosmetic appearance, better skin adhesion, greater comfort, and less skin irritation.6 These traits also apply to the contraceptive patch. In clinical studies, the transdermal contraceptive system was shown to have statistically better patient compliance than oral contraceptives (OCs); in 1 trial, compliance was better across all age groups (FIGURE 1).7 This may be due in part to the weekly, rather than daily, dosing regimen.