After a review of recent epidemiologic studies, the US Food and Drug Administration (FDA) concluded that there is a higher risk of blood clots in women taking drospirenone-containing oral contraceptives (OCs) than in women taking other progestin-containing OCs.
The FDA now requires that manufacturers add this information to the labels of drospirenone-containing OCs.
Before prescribing these drugs, health-care professionals are strongly advised to weigh the risks and benefits of drospirenone-containing OCs against a woman’s other risk factors for developing a blood clot.
Oral contraceptives that contain drospirenone/ethinyl estradiol are Beyaz, Gianvi, Loryna, Ocella, Safyral, Syeda, Yasmin, Yaz, and Zarah.
Inconsistent results
The studies reviewed by the FDA did not provide consistent estimates of the comparative risk of blood clots associated with various oral contraceptives that did or did not contain drospirenone. Nor did they account for patient characteristics that may influence prescribing and that likely affect the risk of blood clots. For these reasons, it is unclear whether the increased risk of blood clots seen in some of the studies is actually due to drospirenone-containing OCs.
Bayer, the manufacturer of Beyaz, Safyral, Yasmin, and Yaz, will report that some epidemiologic studies reported as high as a three-fold increase in the risk of blood clots for drospirenone-containing products, compared with products containing levonorgestrel or some other progestinsâ€"whereas other epidemiologic studies found no additional risk of blood clots. The labels will include a summary of the previously released results of an FDA-funded study of the blood clot risk.
Risk is still lower than in pregnancy and postpartum
The FDA notes: "To put the risk of developing a blood clot from a birth control pill into perspective: The risk of blood clots is higher when using any birth control pills than not using them, but still remains lower than the risk of developing blood clots in pregnancy and in the postpartum period."1
The likelihood of developing a blood clot is greatest (40 to 65 cases for every 10,000 women) during the postpartum period; moderately risky (5 to 20 for every 10,000) during pregnancy; less risky (3 to 9 for every 10,000) in combination oral contraceptive users; and least risky (1 to 5 for every 10,000) for nonpregnant, noncombination oral contraceptive users.1
For the US FDA Drug Safety Communication published on April 10, 2012, click here.
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