Ibuprofen may lessen benefit of daily aspirin

Patients taking ibuprofen for pain and aspirin to reduce their chances of a second stroke may not be receiving the full benefit of their prevention efforts, according to a study in The Journal of Clinical Pharmacology in January.

Researchers assessed the combined effect of these two drugs on 10 healthy volunteers and 18 others who were using the medications for pain relief and stroke risk reduction. The blood-thinning effect of the aspirin was blunted in the healthy participants, while those who were attempting to prevent a stroke appeared to be resistant to the effects of aspirin until ibuprofen was discontinued. Also, 13 people in the latter group experienced a stroke while taking these two drugs together over a 27-month period.

"Those strokes were preventable," said Francis M. Gengo, PharmD, lead author and associate professor of pharmacy practice and neurology at University at Buffalo in New York.

Several studies have suggested that ibuprofen may interfere with the vascular benefits of aspirin. It's unclear how clinically relevant this phenomenon may be, but the Food and Drug Administration issued a statement in September 2006 calling for physicians to be aware of this interaction. The authors of this latest piece are calling for greater awareness of the possibility regarding stroke prevention.

"This interaction between aspirin and ibuprofen or prescription NSAIDs is one of the best-known but well-kept secrets in stroke medicine," said Dr. Gengo.

Physicians treating patients at high risk for a stroke or myocardial infarction responded that those taking daily aspirin should be cautioned against also taking ibuprofen regularly. This study, however, was too small to be conclusive, although it did make sense in light of findings by others who have investigated the issue.

"The only limitation is the very limited sample size, but this fits very well with previously published studies," said Tobias Kurth, MD, ScD, an epidemiologist at Brigham and Women's Hospital and assistant professor of medicine at Harvard Medical School in Boston.

Cardiologists also expressed reservations about this paper's conclusions because, although aspirin reduces the risk of stroke, it does not cut it to zero. The strokes seen during the study may have occurred with or without the use of ibuprofen.