Ibuprofen, one of a class of pain-relievers known as NSAIDs, does not contain aspirin, but taking the two medications together may lessen the blood-thinning effects of aspirin, as reported by a study conducted by researchers at the University of Buffalo. The research found that patients who were taking aspirin to prevent platelet aggregation and to reduce the chances of a repeat stroke became unresponsive to the blood-thinning effects of aspirin when ibuprofen was taken at the same time. The research showed that platelet aggregation resumed within 4 to 6 hours when dosages of ibuprofen and aspirin were combined.
A dosage of aspirin taken as a blood-thinner normally inhibits the aggregation of platelets for 72 to 96 hours. When taken close to a dosage of ibuprofen, the anti-platelet effect was not observed for 18 to 20 hours each day during the research study. In an advisory last updated June, 2014, the Food and Drug Administration also warned that aspirin may become less effective if taken with ibuprofen and advised that patients taking aspirin to prevent strokes should consult with their doctor to determine the best timing for the two medications.
Ibuprofen is sold in generic form and under trade names such as Advil and Motrin. At first marketed as a prescription drug, ibuprofen became an over-the-counter medication in the United States during the 1980s.