Treating heart attack patients with the anti-clotting drug clopidogrel as well as aspirin could prevent thousands of deaths worldwide, claim researchers.

"If early clopidogrel therapy was given in hospital to just one million of the 10 million patients who have a heart attack every year then it would, on present evidence, prevent about 5000 deaths and 5000 non-fatal reinfarctions [heart attacks] and strokes," said lead researcher Dr Zhengming Chen from the University of Oxford in the UK.

Dr Chen and colleagues studied almost 46,000 patients admitted to one of 1250 hospitals in China with suspected heart attacks. Participants were randomly assigned to receive 75 mg/day clopidogrel or a dummy medication (placebo) in addition to standard aspirin treatment until they had spent 4 weeks in hospital or were discharged.

The team found that, compared with aspirin alone, the combination of aspirin and clopidogrel reduced the risk of death, recurrent heart attacks, or stroke during the study period by an additional 9% and led to a further 7% reduction in deaths.

People in the UK with angina are already given clopidogrel to reduce their risk of heart attacks, but doctors have been wary of prescribing the drug to heart attack patients because of fears over an increased risk of major bleeding.

However, Dr Chen and his team say clopidogrel should now be considered as standard emergency treatment for heart attack patients.

Commenting on the study, published in The Lancet, Professor Jeremy Pearson, associate medical director of the British Heart Foundation, said: "This is the most recent of several studies that have shown that clopidogrel has benefits for patients with vascular disease.

"Its use is already well established for patients with unstable angina and this study confirms that it is safe and effective also in heart attacks."