TIME Magazine, April 25, 2011
Newer Birth Control Pills Carry a Higher Risk of Blood Clots
Two studies published in the British Medical Journal confirm that birth control pills increase the risk of blood clots.
The two trials, one of which involved a U.S. population of women and the other a British cohort, found that women taking newer forms of oral contraceptives, which include drosperinone, a synthetic version of the hormone progesterone, increased their risk of developing a blood clot by two or three times over those taking older birth control pills that rely on a different form of the hormone known as levonorgestrel.
The blood clots were not fatal, and the absolute number of cases was small, but the results highlight what doctors have known ever since birth control pills were approved that the mix of hormones needed to prevent pregnancy also promote clotting factors.
Newer oral contraceptives include Yaz, Yasmin and Ocella, and their makers all include warnings about increased risk of blood clots on the drugs' labels. Bayer, which manufactures Yaz and Yasmin, said in a statement that the study had "significant flaws" and defended the safety of its product:
Given the already large and robust scientific body of evidence, in Bayer's opinion, these studies do not change the overall assessment about the safety of Bayer's oral contraceptives.
Dr. Grace Lau, an obstetrician and gynecologist at New York University Langone Medical Center, said that while the absolute risk of developing a blood clot on the newer contraceptives was small 30.8 per 100,000 women years compared with 12.5 events in the control group in the U.S. study there is still an increased risk. "If a woman has been on Yaz and has had no problems with it, then I don't have a problem continuing to write her prescriptions for it," she says. "But for someone who hasn't been on a contraceptive, as a provider I think about what would decrease their risk and I want the best for my patients. So this may not be the first thing I give them, since it may not be the best option they could possibly get."
However, Lau stresses that the absolute risk for individual women is still low, so each woman should decide for herself which option is right for her. Birth control pills can cause other side effects, from spotting to cramps, and some women may respond better to the newer pills. Taking birth control, however, is not indicated for women who have a history of blood clots or are over 35 and smoke, since smoking increases the risk of clots. By Alice Park
Pharmalot, April 25th, 2011
Newer Birth Control Pills Increase Blood Clot Risks
Trying to prevent one unwanted event may cause another. Women who use a newer type of birth control pill containing a hormone called drospirenone, such as Bayers Yaz and Yasmin, are more likely to develop blood clots than those who take an older oral contraceptive, according to a pair of studies published in BMJ. However, the overall risk of developing a clot in the lungs or legs was still low.
One study reviewed insurance data for US women aged 15 to 44 who took a contraceptive pill containing either drospirenone or levonorgestrel after January 2002, and compared 186 women who had had a blood clot with 681 who had not. Those taking the newer pill had a 2.3 times greater risk for a blood clot, although the absolute risk was small - 30.8 per 100,000 among those taking drospirenone, compared to 12.5 per 100,000 in women taking levonorgestrel (read the abstract here).
The findings “provide further evidence that levonorgestrel oral contraceptives appear to be a safer choice, says Susan Jick, a professor of epidemiology in the School of Public Health of Boston University and principal author of the study.
The other study, which reviewed use among similarly aged women in the UK, found a three-fold elevated risk for blood clots among women taking the newer version of the pill. That translated to 23 per 100,000 women in the drospirenone group and 9.1 per 100,000 women in the levonorgestrel group (here is the other abstract).
“Prescribing lower-risk levonorgestrel preparations as the first line choice in women wishing to take an oral contraceptive would seem prudent, says Lianne Parkin, a senior lecturer in the School of Medicine at the University of Otago in Dunedin, New Zealand and senior author of the second paper.
The results are not good news for Bayer, which faces numerous lawsuits over its contraceptives. Nearly 6,900 lawsuits are pending in the US over alleged injuries and deaths relating to Yaz and Yasmin, as well as generics. The lawsuits allege Yaz and Yasmin have risks beyond those of traditional birth control pills and Bayer too aggressively promoted the pills without disclosing higher risks. Bayer was warned by the FDA in 2008 that TV ads were misleading and did not disclose added risks (see here).
In a statement, Bayer questioned the methodology of the studies and contended the results do not offer any new insights. “Bayers assessment, based on its review to date, is that the manner in which the authors applied the study methodology reported in these two publications and the databases used provide less reliable conclusions than are available from existing scientific evidence around the risk of developing venous thromboembolism (VTE), or blood clots, with combination oral contraceptives (COCs). Given the already large and robust scientific body of evidence, in Bayers opinion, these studies do not change the overall assessment about the safety of Bayers oral contraceptives. By Ed Silverman
Why Bayer Will Likely Ignore Studies of Blood Clot Risks in Its Contraceptives
By Jim Edwards/BNET | April 25, 2011
Three new studies showing a higher risk of lethal blood clots or gallbladder disease in women using birth control pills like Yaz put contraceptive maker Bayer and the FDA on notice: new warnings may need to be added to the product. Whether either of them will actually do anything about it remains an open question.
The studies will hurt Bayer as it faces 6,850 lawsuits alleging that Yazs drospirenone ingredient is more dangerous than those used in competing pills. About 190 deaths from heart attack, stroke or pulmonary embolism have been associated with Yaz and similar pills.
Two of the studies looked at blood clots; the third looked at gall bladder disease:
· In the U.S., researchers looked at a database containing almost all women who took an oral contraceptive containing either drospirenone (Yaz) or levonorgestrel since 2002. It found a 2.3 times greater risk of blood clots with drospirenone.
· In the U.K., researchers found 3.3 times more blood clots in drospirenone users.
· And in Canada, researchers looking at U.S. data found “a small, statistically significant increase in the risk of gallbladder disease but they concluded it was “unlikely that these differences are clinically significant.
Contraceptive makers have historically been slow to act when faced with evidence that their products may be more dangerous than competitors. Johnson & Johnson (JNJ) settled hundreds of cases alleging its Ortho Evra patch carried a higher risk of blood clots in 2008. About 130 deaths are associated with that product. But the patch is still sold by J&J and an FDA “review of the product is in its third year.
The FDA does not require companies to wait until it asks for new risk warnings to be added, but it is rare for a company to voluntarily tighten the instructions for its drugs on their own. Doing so is an admission that the company knows there is a problem, and companies dont like making such admissions. Nonetheless, courts have not looked kindly on companies that failed to act after they learned of problems on their products.
It is unlikely that Bayer will do anything to alert doctors to think more carefully before prescribing Yaz and its sister brands (Yasmin, Beyaz, Natazia, Angeliq and Ocella). The company already sponsored guidelines to ob/gyns suggesting the drug is no more risky than others; previous studies have gotten contradictory results; and Yaz is Bayers second-biggest product by sales.