Recent Advances in Oral and Transdermal Contraception

Peggy Piascik, PhD

Disclosures

US Pharmacist. 2008;33(9):19-23. 

In This Article

Emergency Contraception and Summary

In August 2006, Plan B was approved for OTC sale to women aged 18 years and older. Plan B contains two tablets of 0.75 mg levonorgestrel. The product labeling states that the tablets are to be taken 12 hours apart starting within 72 hours of unprotected sex. Recent findings suggest that the regimen is equally effective if the tablets are taken as one dose.[29] Additional evidence suggests that Plan B may be effective taken up to five days after intercourse; however, this use is not approved.[30] Women may purchase Plan B to keep for future use; this concept, called advance provision, is recommended by many HCPs because it eliminates delays in starting therapy. Concerns that widespread availability of Plan B would increase sexual risk-taking behavior have not been borne out in clinical studies.[27]

COCs may be used for emergency contraception also. Two to five tablets of a COC that contains levonorgestrel as the progestin are used in the Yuzpe regimen, which comprises 100 mcg to 120 mcg ethinyl estradiol combined with 0.5 mg to 0.6 mg levonorgestrel. Plan B is preferred to the Yuzpe regimen because it has fewer adverse effects, particularly nausea and vomiting, that may decrease the regimen's effectiveness.[32]

The copper IUD can be used in women who want emergency as well as regular contraception. The proposed mechanism of action is to impair fertilization, alter sperm motility, and impede implantation.[32] The IUD may be inserted up to five days after unprotected sex. IUD use is contraindicated in cases of sexual assault where there is a high risk of sexually transmitted disease.[32]

Mifepristone, used in the U.S. as an abortifacient since 2000, has been examined for emergency contraception. It has multiple mechanisms of action, depending on when in the menstrual cycle it is administered. A single dose of 10 mg to 50 mg has been shown to be highly effective for preventing pregnancy.[32] The dose is effective up to five days after unprotected sex. Impediments to the drug's use are that the only dose available in the U.S. is a 200-mg tablet; prescriber availability is limited to physicians who have registered with the FDA to obtain access; and the drug is likely to delay the onset of menstrual bleeding versus other methods of emergency contraception.[29]

A number of new contraceptive methods have been introduced in the U.S. These methods are safe and effective for contraception. They also decrease adverse effects and confer some noncontraceptive benefits.

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