Drospirenone-containing contraceptives pills, such as Yasmin, are associated with a significantly higher risk of deep vein thrombosis and pulmonary embolism than older-generation medicines, new research finds.
The Israeli study showed a 43% increased risk of venous blood clots with drospirenone compared with third-generation contraceptives and a 65% increased risk compared with second-generation drugs.
The risk of venous clots was found to be highest in the early months of use, but there was no increase in arterial blood clots or of transient ischemic attack or stroke.
Medicines regulators, including most recently the US Food and Drug Administration, have warned of the risk of blood clots with drospirenone-containing oral contraceptives, but the researchers said information on adverse events had been conflicting.
Study leader Dr Naomi Gronich, a clinical researcher in the Department of Community Medicine and Epidemiology in Tel Aviv, said: ‘With the increasing use of drospirenone-containing contraceptives, it is important to raise awareness of the increased, albeit small, risk of venous thromboembolism relative to third-generation pills, especially among those who are older or obese.'
According to a rapid review issued in May by the National Prescribing Centre around 17% of all standard strength combined oral contraception prescription items dispensed are for the more expensive Yasmin.
Canadian Medical Association Journal 2011, online 7 November
