October 27, 2011 — The US Food and Drug Administration (FDA) today released the final report of an FDA-funded study looking into the risk for venous thromboembolism (VTE) in women taking oral contraceptives containing drospirenone.
As previously reported by Medscape Medical News, on September 26 the FDA said preliminary findings from the study indicate that women who use drospirenone-containing birth control pills have an approximately 1.5-fold increase in the risk of developing blood clots relative to women using other types of hormonal contraceptives. However, the agency said its review of the study was ongoing.
According to the report posted today, the final results add to the "increasing body of evidence" linking drospirenone/ethinyl estradiol (DRSP) tablets to increased risk for VTE relative to standard low-dose combined hormonal oral contraceptives.
In the study, "DRSP was associated with higher risk of [arterial thrombotic event] in new users overall with this finding restricted to women in the 35-55 years age group only," the agency notes.
According to the FDA, the findings also "add to the small body of literature" that shows that the norelgestromin/ethinyl estradiol (NGMN) transdermal patch is associated with higher risk for VTE compared with standard combined hormonal oral contraceptives.
The findings also point to an increased risk for VTE with the etonogestrel/ethinyl estradiol (ETON) vaginal ring relative to standard combined hormonal contraceptive pills. This finding, the agency says, is "new and raises concern but needs to be replicated in other studies."
The study was a retrospective cohort study using data from 4 geographically diverse health plans that included 835,826 women with 898,251 person-years of combined hormonal contraceptive use.
The final cohort included 189,210 person-years of exposure to DRSP, 67,865 person-years of exposure to NGMN, 23,910 person-years of exposure to ETON, and 617,265 person-years of exposure to the comparator (combined hormonal contraceptives).
In adjusted analyses, DRSP, NGMN, and ETON were associated with a significantly higher risk for VTE relative to low-estrogen comparators. Estimates of relative risk were 1.7 for DRSP, 1.5 for NGMN, and 1.6 for ETON, according to the report.
The FDA says the findings from the study will be presented and discussed at the joint meeting of the Reproductive Health Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee on December 8.
More information can be found on the FDA's Web site.
In a related finding, the results of a Danish study, published online October 25 in BMJ, suggest that women who use oral contraceptives containing drospirenone, desogestrel, or gestodene may double their risk for VTE compared with users of contraceptives containing levonorgestrel.
Medscape Medical News © 2011 WebMD, LLC
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Cite this: FDA Provides Update on Drospirenone VTE Risk - Medscape - Oct 27, 2011.