Doctors have been warned of the increased risk of bleeding episodes in heart attack patients that are given certain combinations of clot-busting drugs.
Research carried out by doctors from Copenhagen University Hospital found that a combination of the anti-clotting treatments aspirin, clopidogrel and vitamin K antagonists such as warfarin tripled, or even quadrupled, the risk of a patient suffering from bleeding.
The study looked at more than 40,000 heart attack patients over a 16-month period who had been given varying clot-busting treatments. In comparison with aspirin alone, clopidogrel increased the risk of bleeding by 1.3 times and vitamin K antagonists 1.2 times. Combinations of aspirin plus clopidogrel raised the risk 1.5-fold, and when aspirin and vitamin K antagonists were combined the risk almost doubled. A combination of clopidogrel and vitamin K antagonists led to a 3.5-fold increase in risk, while a triple therapy involving all three drugs quadrupled the risk.
The research authors have warned doctors of the need to carry out suitable assessments of patients before considering a combination of the drugs.
Dr Rikke Sorensen, who led the study, said: “‘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.”
June Davison, cardiac nurse at the British Heart Foundation pointed out that while aspirin and clopidogrel were routinely prescribed to treat heart attack patients in the UK, vitamin K antagonists were not.