Warfarin seen as treatment of choice to cut stroke risk
Warfarin, an anti-clotting drug, is the best treatment to prevent stroke in patients with an abnormal heart rhythm despite side effects such as risk of bleeding, researchers said on Friday.
A trial of patients with the disorder known as atrial fibrillation uncovered evidence that warfarin was superior to the combined treatment of the blood-thinner Plavix plus aspirin in reducing strokes.
Plavix, or clopidogrel, is sold by Sanofi-Aventis and Bristol-Myers Squibb Corp in the United States.
"Oral anticoagulants such as warfarin remain the treatment of choice for preventing stroke in patients with atrial fibrillation,” Dr Stuart Connolly, of McMaster University in Hamilton, Ontario said in an interview.
Atrial fibrillation is a condition that affects more than one percent of the population. Patients have a five times higher risk of suffering from a stroke than other people.
Warfarin, which is also sold under the brand name Coumadin, can reduce the risk of stroke by two-thirds but it is linked with an increased risk of major bleeding. Patients must be monitored and should avoid certain foods.
The study was designed to see if Plavix plus aspirin, which acts through different mechanisms in the body, would be a safe and effective alternative to warfarin.
“It turned out not to be in this study,” said Connolly.
More than 6,700 patients with atrial fibrillation who signed up for the four-year trial were given warfarin or the combined treatment of Plavix and aspirin.
After two years, the study was halted when the researchers found the risk of a stroke was 3.9 percent in the warfarin patients and 5.6 percent in the combined treatment group.
“There was no point going on. It was considered unsafe for patients to remain on clopidogrel plus aspirin,” said Connolly.
He added that most people in the study had already been taking warfarin. They either remained on the drug or were switched to the combined treatment.
“It’s likely that those people who were used to warfarin did better on it than you might expect from the average person who has not been exposed to it before,” Connolly added.
In a commentary in the journal Freek Verheugt, of the University Medical Centre St Radboud, in Nijmegen in the Netherlands, said there is no indication to change the current standard treatment of warfarin in atrial fibrillation patients.
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