Nearly 26 million Americans are on daily aspirin therapy to prevent a heart attack, and roughly half are taking the standard dose of 325 mg. But a new study shows that this may be more aspirin than is needed, and lowering the dose can decrease the risk of side-effects while still protecting the heart."The ideal dose of aspirin for the prevention of vascular events has been the subject of much debate," writes Dr. Ron Peters and colleagues in a study recently published on-line in Circulation: The Journal of the American Heart Association.
According to the American Heart Association, as many as 100 million Americans could benefit from daily aspirin therapy. Cardiovascular disease is the nation’s number one killer, claiming the lives of nearly one million Americans every year. Aspirin is proven to help lower the risk of a heart attack.
In the study, the researchers analyzed data from a previously published trial that compared the effects of taking a daily aspirin in combination with an anti-platelet drug called Plavix to prevent heart attack, stroke and recurrent chest pain. This combination was more effective at preventing cardiovascular events than aspirin alone in more than 12,500 patients with unstable angina.
When the researchers went back to look at the bleeding outcomes in this trial they found that low-dose aspirin, or the equivalent of one baby aspirin, was as effective as regular strength aspirin at preventing cardiac events, but the bleeding complications were much lower.
"The risk of bleeding at the highest dose of aspirin given with placebo was higher than the risk of bleeding with the combination of clopidogrel (Plavix) and aspirin in the lowest-dose group," the researchers write.
The types of bleeding they were concerned with was anything significantly disabling, bleeding into the eyes that led to loss of vision, bleeding that required transfusion, bleeding in the head, or bleeding in the stomach lining.
Bleeding complications, mostly stomach and surgical-related, were more common as the doses of aspirin got higher whether the patient had undergone angioplasty, coronary artery bypass surgery or simple monitoring to treat their angina. Bleeding occurred more often when other anti-clotting drugs were used in combination with Plavix and aspirin, but the researchers suggest this was probably do to the addition of those drugs.
Since Plavix and aspirin are now recommended as long-term combination therapy for patients with unstable angina, the researchers say it is important for patients to take the dose that will cause the least amount of side-effects. They conclude that taking a daily aspirin between 75 and 100 mg, or one baby aspirin, is the safest dose to prevent a future heart attack.
