At least this is what a recently published review of the literature on bleeding rates when aspirin and other anti-thrombotic agents are used together for secondary stroke prevention seems to imply. The study showed a significantly higher risk of bleeding when aspirin is used in combination with clopidogrel, or coumadin. The specific bleeding rates reported were as follows: 4.8% with aspirin alone, 2.9% with clopidogrel alone, 3.6% with aspirin plus aggrenox, but a whopping 10.1% with aspirin plus clopidogrel, and 16.8% with aspirin plus coumadin.
Major bleeding occurred at mean rates of 1% with aspirin alone, 0.85% with clopidogrel, but 1.7% with aspirin plus clopidogrel, and 2.5% with aspirin plus coumadin. And sadly this comes along without any added stroke protection when aspirin and plavix are used together. These numbers are concerning and should be considered strongly before aspirin and clopidogrel (plavix) are used for secondary stroke prevention.
That said, aspirin and plavix used together might help prevent some strokes, as shown by study published in the New England Journal of Medicine in which the combination of aspirin and clopidogrel decreased the risk of first strokes in people with atrial fibrillation who are unable to take coumadin for various reasons. Although the risk of bleeding was also greatly increased in that population as compared to those taking aspirin alone, the benefits of the combination of aspirin and clopidogrel might outweigh the risks.