FDA Evaluates New Studies on Risk of Birth Control Medications Like Yaz

June 9, 2011

Birth control medications that contain drospirenone, such as widely-used brands Yasmin and Yaz, have yet to be officially recalled, but given mounting scientific evidence, it appears the U.S. Food and Drug Administration is carefully weighing the matter.

The studies, published in the British Journal of Medicine in April, reported there was two to three times more risk associated with taking drospirenone than for levonorgestrel-based medications.

Two newly published British studies examined the risk for venous thromboembolism (VTE) or blood clots in women ages 15 to 44 who use birth control pills containing drospirenone versus those who took birth control using a different form of progestin. Progestin is a synthetic female sex hormone typically used in oral contraceptives.

The studies, published in the British Journal of Medicine in April, reported there was two to three times more risk associated with taking drospirenone than for levonorgestrel-based medications.

European regulators are revising prescribing information to reflect these new findings. The European Medicines Agency said the risk of developing blood clots from taking oral contraceptives containing drospirenone was greater than that with pills containing levonorgestrel, but it also said the risk for any type of birth control pill was small.

The FDA released a safety alert stating that it is “currently evaluating the conflicting results from these studies and will look at all currently available information to fully assess the risks and benefits of drospirenone-containing birth control pills.” The agency is not suggesting that women stop taking these drugs without first consulting their physician, but does advise that those taking these types of birth control watch for symptoms of blood clots, which include persistent leg pain, severe chest pain, or sudden shortness of breath.

Health Canada is also reportedly reviewing these studies.

Drospirenone-containing drugs on the market in the United States include Yaz and its generic formulations Gianvi and Loryna; Yasmin and its generic formulations — Ocella, Syeda, and Zarah –; Beyaz; and Safyral. Bayer AG is the leading maker of these drugs.

Birth control pills typically contain both estrogen and progestin; they are able to prevent ovulation and other functions that enable a woman to become pregnant. When these newly formulated drugs were first released on the market, it was thought drospirenone would be less likely to cause dangerous blood clots than existing medications.

NPR reports that four of six studies conducted to date have raised concerns about drospirenone-based contraception. The other two studies, reportedly underwritten by Bayer, found no increased risk.

Susan Jick, director of the Boston Collaborative Drug Research Program and a co-author of the most recent studies, told NPR that the previous studies failed to distinguish between those women taking contraceptives who suffered blood clots from other causes and those who had suffered clots with no obvious cause that might have been caused by birth control.

“If you limit your study to women who have no other cause for their blood clot — they didn’t have a recent surgery or pregnancy or recent injury — you can see the differential effect of blood clots,” she says. Jick also reportedly doesn’t think drospirenone-containing contraceptives will or should be taken off the market.

“Different women react differently to different contraceptives,” Jick says. “There are different kinds of side effects — bloating and other types of things, and certain women feel much better taking one particular kind of pill compared to another, and that has to be taken into consideration as well. So there’s the risk and there’s the benefit and it’s a very personal decision.”

Although blood clots are an extremely rare occurrence in healthy young women, Jick says she would still advise them that “given there is what I could consider strong evidence that the drospirenone pills do increase the risk of blood clots, they should take the older contraceptives that have been shown to have a lower risk.”

The Wall Street Journal reports that sales of Yaz have continued to decline since concerns about drospirenone were first raised in 2009. Bayer AG, the maker of the drug, claims competition in the U.S. from generics is to blame. The publication states that sales of Yaz dropped 13% in 2010 followed by a 16% loss in Q1 2011 to €242 million.

An FDA-commissioned study exploring the association of blood clots with hormonal contraception should be released later this summer.

Linda Dailey Paulson is a freelance journalist for Providian Medical, a leading seller of refurbished ultrasound equipment specializing in OB/GYN systems. Providian has helped hospitals and clinics around the world save thousands of dollars on expensive medical equipment. You can find out more at ProvidianMedical.com. Photo by gnarlsmonkey on Flickr.

Were you affected? Click Here for a free case evaluation!