Novel Contraceptive Methods Offer New Options for Women

In May, the FDA approved 2 new birth control pills that use novel methods to reduce the hormonal fluctuations common with traditional regimens. Two other products that are in the final stages of development may be on the road to approval.

Improved Side-Effect Profile

Extended regimen. The first extended-regimen oral contraceptive that replaces placebo with low-dose estrogen (Seasonique; Barr Pharmaceuticals) consists of 84 active tablets (0.15 mg levo-norgestrel/0.03 mg ethinyl estradiol) and 7 low-dose (0.01 mg) estrogen tablets. Substituting low-dose estrogen for placebo minimizes the occurrence of hormonal fluctuations, bloating, and breakthrough bleeding often associated with other oral contraceptives. FDA approval was based on efficacy and safety data from 2 randomized, open-label trials involving 2500 women aged 18 to 40 years.

Monophasic agent. The first monophasic product to contain the new pro-gestin drospirenone (Yaz; Berlex) consists of 24 days of active hormone therapy and 4 days of placebo pills. Combined with the long, 30-hour half-life of drospirenone, the 24-day regimen helps mitigate some of the monthly hormonal fluctuations seen with the traditional 21 days of active therapy/7 days of placebo regimen. In a clinical trial involving 1027 women who completed 11,480 treatment cycles, Yaz was 99% effective in preventing pregnancy. Because drospirenone can increase the risk for hyperkalemia, this agent is contraindicated in women with renal or adrenal insufficiency or hepatic dysfunction. Serum potassium levels should be monitored in women taking medications that have potassium-increasing effects.

On the Horizon

Contraception

Eur J Contracept Reprod Health Care

Implantable contraceptive. Last year the FDA sent an approvable letter to the manufacturer of Implanon (Organon), an implant that provides up to 3 years of protection against pregnancy. It could become the first implantable contraceptive available to US women since Norplant was taken off the market in 2002. Studies have found it to be safe, effective, and readily reversible (. 2005;71: 319-326), although up to 20% of women have the implant removed because of side effects, primarily bleeding disturbances (. 2004; 9:278-284).

Noncyclic contraceptive. The results of 2 clinical studies presented at this year’s American College of Obstetricians and Gynecologists annual meeting suggest that an investigational, low-dose noncyclic contraceptive (Lybrel; Wyeth Pharmaceuticals) is as safe as traditional 21-day regimens and that up to 99% of women return to menses after discontinuing use (Obstet Gynecol. 2006;107[suppl]:S3). If approved Lybrel (90 µg levonorgestrel/ 20 µg ethinyl estradiol) could be the only combination agent that is taken 365 days a year without a placebo or pill-free interval.