Comparison	Results
Aspirin vs. clopidogrel (Plavix)21	No difference in stroke rates
Aspirin vs. aspirin plus clopidogrel22	No difference in stroke rates, but more bleeding with aspirin plus clopidogrel
Aspirin vs. dipyridamole (Persantine) vs. aspirin/ dipyridamole (Aggrenox)23	Combination of aspirin and dipyridamole resulted in fewer strokes than did either drug alone
Clopidogrel vs. aspirin/dipyridamole24	No difference in stroke rate, but aspirin/dipyridamole had higher rate of discontinuation because of adverse effects