Previous studies have suggested that ibuprofen interferes with the effects of aspirin.
In the study patients were taking either high dose, 400mg a day lumiracoxib, a type of drug known as a COX-2 inhibitor, or ibuprofen, 800mg at three times a day, or naproxen at 500mg twice daily, both of which are traditional non-steroidal anti-inflammatory drugs (NSAIDs).
The results showed that there was no difference in the total number of heart attacks and strokes among participants at low risk of cardiovascular disease, irrespective of their drug treatment. But high risk patients taking aspirin and ibuprofen were around nine times as likely to have heart attacks and strokes over one year as those on lumiracoxib.
Among high risk patients not taking aspirin, the rate of heart attacks or strokes was higher for those on the COX -2 inhibitor than it was for those on naproxen, but no higher than for those on ibuprofen. Participants taking ibuprofen also developed congestive heart failure more often than those on the COX inhibitor.
The authors say that their findings suggest that ibuprofen interferes with the blood thinning properties of aspirin in patients at high risk of cardiovascular disease.