Conflicting Study Data Drive FDA Review of Contraceptives Containing Drospirenone

The FDA announced this week that it is assessing two studies recently published in BMJ as part of the agency's ongoing safety review of birth control pills that contain drospirenone, such as the brand-name products Yaz and Yasmin.

A study conducted in the United States found that the risk of nonfatal venous thromboembolism among women using oral contraceptives containing drospirenone was twice that of women using products containing levonorgestrel. A study conducted in the United Kingdom found that the use of drospirenone was associated with a threefold higher risk for venous thrombolic events, or VTEs, compared with levonorgestrel.

Previous research had yielded conflicting results. Two studies published in BMJ in 2009 also found that drospirenone was associated with an increased risk for VTEs. However, two postmarketing studies required by regulatory agencies, including the FDA, did not report any difference in the risk of blood clots between drospirenone-containing products and products containing other progestins, including levonorgestrel. Current labeling of drospirenone products includes information about those conflicting studies.

The FDA said in a May 31 drug safety communication that the agency is reviewing the two most recent studies and all other available information to assess whether there is a greater risk of VTEs in women who use drospirenone products. Furthermore, findings from an FDA-commissioned study exploring the association of blood clots with use of hormonal contraceptives are being finalized and reviewed. The agency said results of that study, which involved more than 800,000 women, are expected later this summer.

For now, the agency has issued the following information for physicians:

Women using birth control that contains drospirenone should not stop taking it without first consulting their physician. A complete list of birth control pills that contain drospirenone is available online.

In addition to prevention of pregnancy, some contraceptives containing drospirenone are approved to treat symptoms of premenstrual dysphoric disorder or moderate acne, as well as to raise folate levels, in women who choose to use an oral contraceptive for birth control.