What are contraceptive transdermal patches?

Updated: Oct 16, 2019
  • Author: Frances E Casey, MD, MPH; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Answer

Available in the United States since 2001, the contraceptive transdermal patch releases estrogen and progesterone directly into the skin (Ortho Evra, Ortho-McNeil Pharmaceutical; Raritan, NJ). Each patch contains a 1-week supply of hormones of both norelgestromin and ethinyl estradiol. It releases a sustained low daily dose of steroids equivalent to the lowest-dose oral contraceptive. In August 2002, the FDA listed a failure rate for the patch of 1 pregnancy per 100 women per year, similar to that of other combination methods. Advantages include greater compliance and decreased adverse effects, such as nausea and vomiting, due to the avoidance of the first-pass effect. However, the patch may cause skin irritation, and, if it is removed unnoticed, such as from showering, this may compromise efficacy. Disadvantages and contraindications are similar to those of combination oral contraceptives. It may be less effective for women who weigh more than 198 pounds.

Ortho Women's Health, a unit of Ortho-McNeil Pharmaceutical Inc, updated the warnings section of the prescribing information for the Ortho Evra patch after new studies revealed that its pharmacokinetic profile differs from the pharmacokinetic profile for combination oral contraceptives. Findings noted a higher steady state concentration and lower peak concentrations in the patch as compared with combination oral contraceptives. Average concentrations at steady state for ethinyl estradiol are approximately 60% higher in women using Ortho Evra and peak concentrations are approximately 25% lower in women using Ortho Evra.

This led to a "black box" warning from the FDA in November, 2005. This announcement warned about higher exposure to estrogen for women using the weekly patch compared with those taking a daily combination oral contraceptive containing 35 mcg of estrogen. The new bolded warning specifically states that women who use Ortho Evra are exposed to about 60% more total estrogen in the blood than if they were taking a typical combination oral contraceptive containing 35 mcg of estrogen. Again, peak blood levels of estrogen are about 25% lower with Ortho Evra than with combination oral contraceptive. While the estrogen level with the patch remains constant for 1 week until the patch is removed, the peak blood levels with a daily combination oral contraceptive rapidly decline to levels that are lower than the Ortho Evra levels. The increased estrogen exposure may increase the risk of side effects, such as a thromboembolic event.

These data contrast with those of another study, conducted by the Boston Collaborative Drug Surveillance Program, which looked at the risk of heart attack, stroke, and venous thromboembolic events in first-time users of the patch. In this study, published online in the journal Contraception, the authors found that "the risk of nonfatal venous thromboembolic events for the contraceptive patch is similar to the risk for oral contraceptives containing 35 mcg of ethinyl estradiol and norgestimate." [15] In 2006, the FDA announced that it plans to closely watch the conflicting preliminary data on the risk of thrombosis for women who use Ortho Evra compared with those who take a combination oral contraceptive.


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