Ibuprofen Can Prevent Aspirin's Ability to Thin Blood

A study of nonprescription nonsteroidal anti-inflammatory drugs has shown that taking ibuprofen before aspirin prevents aspirin's ability to thin the blood. This means that heart patients taking a daily low dose of aspirin to protect against heart attacks may lose their protection by taking ibuprofen. Conducted by researchers from the University of Pennsylvania (Philadelphia, PA, USA), the study was published in the December 10, 2001, issue of the New England Journal of Medicine.

The researchers studied ibuprofen, diclofenac, and acetaminophen, as well as refocoxib. They found that taking aspirin two hours before ibuprofen posed no problem, but when ibuprofen was taken before aspirin, it prevented aspirin's ability to thin the blood. Also, patients taking ibuprofen three times a day still had enough in their systems the next morning to counteract the effects of aspirin taken two hours before their morning dose of ibuprofen. This interaction did not occur with rofecoxib, diclofenac, or with 1000 mg of acetaminophen.

"We know that aspirin works to protect the heart by acting as a blood thinner; that is, it prevents clotting by inactivating the enzyme that makes platelets stick together,” said Dr. Garret A. Fitzgerald, director of the Penn Center for Experimental Therapeutics. "This study tells us that ibuprofen can prevent this from happening by denying aspirin access to the enzyme's active site.”



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