Yasmin: Update on risk of venous thromboembolism

It has long been recognised that all combined hormonal contraceptives, including Yasmin, are associated with a small increase in the risk of venous thromboembolism (VTE), including deep venous thrombosis and pulmonary embolism, compared with no use. For a given dose of oestrogen, the absolute incidence of VTE varies according to the type of progestogen but is, for all combined oral contraceptives (COCs), very small. With all COCs the risk is greatest in the first year of use.

Yasmin contains drospirenone, a relatively new progestogen. Yasmin was first licensed in 2000 and became available for use in the UK in April 2002. In England it is estimated that Yasmin accounts for about 11% of prescriptions dispensed for all combined oral contraceptives in 2008/09.The NHS Information Centre for Health and Social Care. Prescription Cost Analysis 2008. Published April 21, 2009. See www.ic.nhs.uk. It is estimated that about 19% of prescriptions for Yasmin are for first-time use. Data derived from IMS Health Disease Analyzer - Mediplus. October 2008–September 2009, by the MHRA.

The incidence of VTE in association with the use of levonorgestrel, desogestrel and gestodene-containing pills has been studied extensively. Overall, these studies have shown that women who use desogestrel or gestodene-containing pills have a slightly higher risk of developing VTE than those who use levonorgestrel-containing pills. Because Yasmin was licensed relatively recently, fewer studies on its associated risk have been carried out.

In 2006, the results from two large prospective cohort studies (EURAS and Ingenix)Dinger JC, et al. Contraception 2007; 75:344–54.Seeger JD, et al. Obstet Gynecol 2007; 110: 587–93. suggested that the risk of VTE in Yasmin users is comparable with that for other contraceptives that contain a similar level of oestrogen, including those containing levonorgestrel. More recently, the results from a Danish cohort studyLidegaard Ø, et al. BMJ 2009; 339: b2890 and a Dutch case-control studyvan Hylckama Vileg A, et al. BMJ 2009; 339: b2921. have suggested that this risk may be slightly higher than previously estimated and somewhere between the risk associated with levonorgestrel-containing pills and with desogestrel or gestodene-containing pills (relative risks for the comparison of Yasmin with levonorgestrel-containing pills: 1·64; 95% CI 1·27–2·10 and 1·7; 0·7–3·9, respectively).

Because of some limitations in the methodology of these recent studies, further analyses are needed before any firm conclusions can be drawn. In the meantime, when jointly discussing the choice of contraceptive with an individual woman, prescribers should be aware of the new evidence and take into consideration her medical history and any contraindications.

All hormonal contraceptives are highly effective and safe, and have important health benefits, including those from avoiding unplanned pregnancy. The risk of a venous thrombosis in women who use Yasmin, as for all combined oral contraceptive pills, is smaller than the risk of VTE associated with pregnancy.

Product information for Yasmin, as for all COCs, already contains extensive warnings about the risk of VTE and these will be updated to reflect the new data.

See also the European Pharmacovigilance Working Party (PhVWP) monthly report, March 2010.

Article citation: Drug Safety Update April 2010, vol 3 issue 9: 2.