Formulations with drospirenone linked to higher risk of clots than those with levonorgestrel
FRIDAY, April 22 (HealthDay News) -- Oral contraceptives containing drospirenone appear to be associated with a higher risk of non-fatal venous thromboembolism than formulations containing levonorgestrel, according to two studies published online April 21 in BMJ.
Susan S. Jick, D.Sc., of the Boston University School of Medicine, and colleagues compared the risk of non-fatal venous thromboembolism in women who received oral contraceptives containing drospirenone with that of women who received oral contraceptives containing levonorgestrel. After adjusting for potential confounders and prescribing biases, the investigators found that the risk of non-fatal venous thromboembolism among users of oral contraceptives containing drospirenone was approximately twice that of those using formulations containing levonorgestrel (odds ratio [OR], 2.3).
In another study, Lianne Parkin, Ph.D., of the University of Otago in Dunedin, New Zealand, and colleagues compared the risk of non-fatal idiopathic venous thromboembolism in current users of a combined oral contraceptive containing drospirenone and current users of oral contraceptives containing levonorgestrel. The investigators found that the risk of non-fatal idiopathic venous thromboembolism was three-fold higher among women who used a combined oral contraceptive containing drospirenone as compared to those using formulations containing levonorgestrel (OR adjusted for body mass index, 3.3).
"This study adds to emerging evidence that use of the oral contraceptive containing drospirenone is associated with a higher risk of venous thromboembolism than are preparations containing levonorgestrel," Parkin and colleagues write.
Abstract - Jick
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Abstract - Parkin
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