Aspirin's Effect on Stroke Risk Destroyed by Ibuprofen

Stroke patients who use ibuprofen for arthritis pain or other conditions while taking aspirin to reduce the risk of a second stroke undermine aspirin's ability to act as an anti-platelet agent, reports a new study.

Researchers at the University at Buffalo (NY, USA) examined a cohort of patients seen by physicians at two offices of the Dent Neurologic Institute (Buffalo, NY, USA). A cohort of 28 patients treated with aspirin for secondary stroke prophylaxis while concomitantly taking ibuprofen--a nonsteroidal anti-inflammatory drug (NSAID)--were identified, and all were found to have no anti-platelet effect from their daily aspirin. An additional 10 normal volunteer subjects underwent three randomized treatment sessions: aspirin 325 mg alone, ibuprofen 400 mg alone, and ibuprofen 400 mg, followed by dosing with aspirin 325 mg 2 hours thereafter.

The researchers found a significant reduction in both the magnitude and duration of aspirin's inhibitory effect on platelet aggregation when ibuprofen was given prior to aspirin administration in the normal volunteer subjects. Of the 28 patients in the cohort, 18 returned for follow-up testing during a 27-month follow-up period; none of these 18 patients demonstrated inhibition of platelet aggregation while on both NSAID and aspirin. Notably, 13 of these 18 patients (72%) had experienced a recurrent ischemic episode while taking aspirin and NSAIDs concomitantly. The researchers subsequently found that when these patients had returned for a second neurological visit after discontinuing NSAID use and were tested again, all had regained their aspirin sensitivity and its ability to prevent blood platelets from aggregating and blocking arteries. The study was published in the January 2008 issue of the Journal of Clinical Pharmacology.

"This interaction between aspirin and ibuprofen or prescription NSAID's is one of the best-known, but well-kept secrets in stroke medicine,” said lead author Francis M. Gengo, Pharm.D., of the department of neurology. "It's unfortunate that clinicians and patients often are unaware of this interaction. Whatever number of patients who have had strokes because of the interaction between aspirin and NSAIDs, those strokes were preventable.”

"When I lecture to pharmacy students, I tell them 'Please, you have a responsibility to the patients you care for',” added Dr. Gengo. "When you counsel a patient taking aspirin or extended release dipyrdamole to lower stroke risk, tell patients they may have some transient headaches, but to avoid ibuprofen. You may have prevented that patient from having another stroke.”


Related Links:
University at Buffalo
Dent Neurologic Institute