The evidence in support of the safety and efficacy of aspirin in the s
econdary prevention of platelet dependent vascular-occlusion is compel
ling. The utility of this drug has stalled the development of potentia
l competitors, such as thromboxane antagonists. The emergence of glyco
protein IIb/IIIa antagonists as the most promising competitors for asp
irin has focused attention on the possibility of delivering these drug
s at an effective dose safely.