A study of male veterans has produced new evidence that an old and controversial drug appears highly effective in preventing strokes among elderly people with a common heart disorder, scientists said this week.
The research involving 525 older men with a condition called atrial fibrillation found that daily doses of the drug warfarin could reduce the stroke risk by 79 percent, said a team led by Dr. Michael Ezekowitz of Yale University and the Department of Veterans Affairs Medical Center in West Haven, Conn.It is the fourth study in four years to find that warfarin can reduce the rate of strokes among people with atrial fibrillation - a disorder that causes a malfunction in the upper chambers of the heart and thus, a tendency to form blood clots that can migrate to the brain, where they can cause strokes.
In the previous three studies, warfarin reduced the stroke risk from 67 percent to 89 percent. Researchers halted all four studies early after warfarin's effectiveness became apparent. A fifth trial by Canadian researchers was halted after the findings of the others became known.
On the basis of all the studies, Ezekowitz recommended that doctors use warfarin routinely to prevent strokes in people with the heart disorder. His report appeared in The New England Journal of Medicine.
Warfarin is an anti-coagulant, or blood-thinning, drug marketed in the United States since the mid-1950s. It is most commonly sold under the brand name Coumadin by E.I. duPont deMours & Co. of Wilmington, Del.
Despite its usefulness in preventing blood clots, doctors have been reluctant to prescribe the drug because of concern that warfarin could cause hemorrhaging.
But the researchers involved in the latest study said they were able to limit side effects by carefully controlling the dose. Among those given warfarin for nearly two years, only six experienced significant bleeding episodes - all involving the gastrointestinal tract.
Based on the findings, "we estimate that if patients were routinely treated with anti-coagulant therapy, the nation could save $2 billion in stroke-associated costs," said Ezekowitz.