Hormonal contraceptives have always carried a warning that they increase the risk of blood clots. It now appears that oral contraceptives containing the progestin drospirenone may increase that risk more than oral contraceptives containing another progestin, levonorgestrel. The Food and Drug Administration (FDA) reviewed several observational studies examining the risk of blood clots in women using these contraceptives, including one that the FDA funded. Although the results of the studies weren't consistent (some found no increase), the FDA has concluded that there is an increased risk of blood clots if the contraceptive contains drospirenone; the increased risk may be as much as three times higher. The drug labels for Beyaz, Safyral, Yasmin, and Yaz now include reports of these studies.

The FDA emphasizes that the risk of blood clots from oral contraceptives is still small, even with the extra increase in risk conferred by drospirenone. Women who become pregnant or deliver a baby actually have a higher risk of developing blood clots than women who use contraceptives.

Nurses should discuss this risk with patients receiving oral contraceptives, and they should also reassure them that drospirenone-containing contraceptives are still safe and effective. Women over 35 years of age who smoke shouldn't take any combination birth control product, whether it contains drospirenone or levonorgestrel. Women who have a history of blood clots, myocardial infarction, or stroke also shouldn't take combination oral contraceptives. Unlike other progestins, drospirenone can increase serum potassium levels, and products with drospirenone should therefore not be used by women with renal or adrenal disease. To read the FDA Drug Safety Communication regarding this issue, go to http://1.usa.gov/Hyl1tu.