Combining certain blood-thinning drugs can quadruple the risk of potentially fatal bleeding for heart-attack patients, according to research published in The Lancet medical journal.
After comparing combinations of aspirin, clopidogrel and vitamin K antagonists such as warfarin, the authors warn that great care should be taken when prescribing such treatments.
Compared with aspirin alone, clopidogrel increased the risk of bleeding 1.3 times, vitamin K antagonists 1.2 times, aspirin plus clopidogrel 1.5 times and aspirin and vitamin K antagonists 2 times.
Worst cases were clopidogrel and vitamin K antagonists, which increased the risk 3.5-fold, and triple therapy involving all three drugs quadrupled the risk.
The researchers, led by Dr Rikke Sorensen, from Copenhagen University Hospital, conclude: “We propose that treatment with triple therapy or dual therapy with clopidogrel plus vitamin K antagonist should be prescribed only after thorough individual risk assessment and careful consideration of the risk-benefit ratio.”
Copyright Press Association 2009