Aspirin vs. Warfarin Debate Ends in a Draw

WEDNESDAY, Nov. 14, 2001 (HealthDayNews) -- Plain over-the-counter aspirin is just as good as the prescription drug warfarin in preventing second strokes for patients at risk because of fat-clogged blood vessels, a study finds.

"The two medications didn't differentiate from one another in any significant way," says lead investigator Dr. J. P. Mohr, director of the stroke unit at Columbia University.

The seven-year study included more than 2,200 people who had had strokes because of blockages in arteries leading to the brain. There was no difference in how well the two treatments worked or in their side effects, says a report in the latest issue of The New England Journal of Medicine.

"Most doctors have taken the view that warfarin is the stronger and more dangerous drug that they can fall back on if aspirin is not effective. The study proved them wrong on both counts," Mohr says.

While aspirin and warfarin are "therapeutic alternatives" in terms of safety and effectiveness, he says, "There is no question that lower cost and convenience favor the use of aspirin. For those who do not want to take warfarin, the benefits of aspirin are so clear that they can switch."

The dose of warfarin, sold as Coumadin by DuPont Pharmaceuticals, must be carefully controlled. Patients must take blood tests, usually every three to four weeks, to avoid problems. Aspirin has no such requirement.

Side effects for aspirin include stomach irritation and, at high doses, dizziness, ringing in the ear and even vomiting. Side effects for warfarin include bleeding in tissue and organs.

An earlier study of patients at high risk of stroke because of the irregular heartbeat called atrial fibrillation showed a distinct benefit of warfarin over aspirin. But atrial fibrillation is involved in only about 15 percent of strokes. The new study was undertaken because the great majority of strokes are due to blood vessel problems.

The finding appears to resolve a debate that has run for decades, says Dr. Robert G. Hart, professor of medicine at the University of Texas, in San Antonio, and an advisor to the National Institute of Neurological Diseases and Stroke, which sponsored the study.

"For 50 years, there has been a debate about the value of warfarin for stroke prevention. A clinical trial was long overdue," Hart says.

The benefits of aspirin in preventing stroke became known in the 1970s, but a trial comparing it with warfarin could not be held until standardized methods of monitoring warfarin were put into place by laboratories all across the country, he says.

The results show "aspirin probably is the first line of treatment, but this gives an alternative to aspirin for people who can't take it for one reason or another," Hart says.

The aspirin vs. warfarin story is not yet complete, he says. Studies are underway to see whether one drug is better than the other for subgroups of patients with specific risk factors. One study involves patients whose risk arises from blockage of arteries within the brain.

What To Do

Anyone at increased risk of a stroke should consult a doctor about the best medication to take and preventive lifestyle measures like exercise and diet.

To learn about stroke risk factors and prevention, go to the American Stroke Association or the National Institute of Neurological Disorders and Stroke.

And here's a site from the Aspirin Foundation of America detailing how that pain reliever works.