London: Aspirin and warfarin, a drug also used as rat poison, are equally effective in preventing heart strokes, a new study says.

However, aspirin was safer because fewer patients suffered bleeding brought on by side-effects such as excessive blood thinning.

The study, coordinated by Columbia University Medical Centre, New York, concluded that for most patients with heart failure, who do not have other problems such as irregular beats or narrowing of the arteries, aspirin would be a better choice.

Warfarin is difficult to take because it interacts with other drugs and some foods, necessitating regular monitoring of patients to check that their blood is not thinning or remaining too sticky, the New England Journal of Medicine reports.

In England in 2010 there were more than eight million prescriptions dispensed for warfarin, according to the Telegraph.

During the study, 2,305 patients in their 60s were randomly assigned to receive either warfarin or 325 mg of aspirin daily and were followed up after an average of six years.

Researchers found that there was no significant difference in the rate of stroke, brain bleed and death, when added together as one outcome, between those on aspirin or warfarin.

The number of strokes in the warfarin group was almost half that of the aspirin group but this was offset by a doubling of major bleeds compared with aspirin, a researcher said.

Shunichi Homma, professor of medicine at Columbia, said: "Since the overall risks and benefits are similar for aspirin and warfarin, the patient and his or her doctor are free to choose the treatment that best meets their particular medical needs. "However, given the convenience and low cost of aspirin, many may go this route."