Table 1. Comparison of Different Antiplatelet Agents

	Aspirin	Clopidogrel	Prasugrel
Mechanism of action	Decreases platelet aggregation by inhibiting formation of thromboxane A2	Inhibits binding of ADP to platelets and thus inhibits activation of GPIIb/IIIa receptor complex	Inhibits binding of ADP to platelets and thus inhibits activation of GPIIb/IIIa receptor complex
Receptor/enzyme targeted	Inhibits platelet cyclooxygenase 1 and 2 enzymes.	Blocks the P2Y₁₂ receptors on platelets	Blocks the P2Y₁₂ receptors on platelets
Reversible	No	No	No
Metabolism	Hydrolyzed to salicylate in GI mucosa and then conjugated in the liver; attains peak serum levels in 1–2 hours	Prodrug; 85% inactivated; 15% oxidized by CYP450 to active thiol metabolite, which attains peak serum levels in 1 hour	Prodrug; major portion oxidized by CYP450 to active metabolite R-138727, which attains peak serum levels in 30 min
Interactions	Proton pump inhibitors do not significantly interact	Proton pump inhibitors reduce serum levels of active metabolite	Proton pump inhibitors do not significantly interact