Routes of administration

Sven O. Skouby

Dept. OB/GYN, Frederiksberg Hospital, University of Copenhagen, Denmark

Women who want safe, effective contraception have many more options than they did only a few years ago. Each option must be weighed carefully according to the needs and lifestyle of each particular woman. Combined oral contraceptives (OCs) are still the preferred choice for the majority of European women although the once daily administration result in fluctuation of hormone plasma levels that may increase the incidence of side effects.

The only contraceptive patch marketed, Evra®, delivers norelgestromin and ethinyl estradiol (EE) transdermally. The patch is applied once a week. Pharmacokinetic studies have shown that the concentrations of norelgestromin and EE are within the ranges seen with OCs containing norgestimate 250 µg and EE 35 µg, but without the peaks and the absorption avoids the first-pass metabolism. The drug levels have been noted to remain unaffected during conditions of heat, humidity, and exercise. The method failure Pearl index is 0.7 and the incidence of adverse similar to that observed during use of OCs. However, the patch seems to have a higher adherence rate for younger users. A month's supply is more expensive compared to OCs but may show cost saving attributed to reduced costs of pregnancy.

The Nuva® vaginal ring is a soft, flexible, transparent polymer and delivers etonogestrel and ethinyl estradiol The hormonal dose is comparable to a pill containing 150 µg desogestrel and 30 µg EE. The advantage of the ring is once-a-month insertion. However, if the ring is out of the vagina for more than 3 hours, a back-up method is needed. When compared to OCs, the incidence of irregular bleeding appears similar. Users of the ring group report higher incidence of vaginal discomfort, but few feel the ring during intercourse.

The contraceptive patch and the vaginal ring offer additional choice for women who wish to use a combined hormonal method of contraception