Baby Aspirin May Not Prevent Stroke

Coated Aspirin Particularly Lacks Blood-Thinning Effect

From the WebMD Archives

Feb. 14, 2003 (Phoenix) -- Taking a daily aspirin is an easy and well-known way to reduce the chances of having a heart attack and stroke, but new research suggests that a "one-size-fits-all" approach to aspirin therapy may not protect your heart or your brain.

"We noticed that a lot of people who have strokes or heart attacks are taking daily aspirin. So we decided to look at why aspirin failed to protect them," says Mark Alberts, MD, director of the stroke program at Northwestern Memorial Hospital in Chicago.

One way that aspirin protects against heart attacks and strokes is by preventing blood clots from forming, says Alberts. So he and his colleagues decided to find out just how effective aspirin is as a blood thinner in people taking daily doses.

The researchers tested blood samples from 126 people who were taking different doses of daily aspirin. Thirty-nine patients took a baby aspirin (81 mg) every other day, every day, or twice per day.

"We were surprised to find that more than half the people taking baby aspirin didn't have their blood adequately thinned," he says. Only 44% of people taking baby aspirin had the full blood-thinning benefit.

He reported his findings at the American Stroke Association's 28th International Conference.

Eighty-seven patients were taking a standard aspirin (325 mg) every day or twice a day. With the higher dose, patients did better, with only 28% showing no blood-thinning effect.

Coated aspirin -- originally designed to help protect the stomach -- was a particular concern. The researchers found that 65% of patients taking coated aspirin were not receiving any blood-thinning benefit from the aspirin. But 75% of people taking regular uncoated aspirin did, says Alberts.

"I think these findings suggest that the one-size-fits-all approach does not work for aspirin therapy," he says.

Larry B. Goldstein, MD, professor of medicine and director of the Duke Center for Cerebrovascular Disease in Durham, N.C., tells WebMD the important message for patients is that there have been a number of large studies that found that aspirin does help prevent heart attacks and stroke and that benefit is not related to dose. "The FDA-approved dose is 81 mg to 325 mg," Goldstein says.

He says, too, that aspirin is more than just a blood thinner. "It has other effects, and we are not yet sure what how aspirin offers its protection." Goldstein was not involved with the study.

Both Alberts and Goldstein did agree on this point: If you are taking aspirin, don't change your dose without checking with your doctor. "Aspirin is a powerful drug and needs to be taken carefully," says Goldstein.

Show Sources

SOURCE: American Stroke Association 28th International Stroke Conference, Paper P291 • Mark Alberts, MD, director, stroke program, Northwestern Memorial Hospital, Chicago • Larry B. Goldstein, MD, professor of medicine; and director, Duke Center for Cerebrovascular Disease, Durham, N.C.

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