Aspirin: Mechanism and Usage as Antiplatelet

Aspirin irreversibly inhibits cyclooxygenase-1, or COX-1, in platelets, preventing the formation of thromboxane A2, which normally promotes platelet aggregation and vasoconstriction. Because platelets cannot synthesize new COX-1, the antiplatelet effect lasts the entire seven to ten day lifespan of the platelet. Low-dose aspirin, typically 81 milligrams daily, is used for secondary prevention of heart attacks and strokes in patients with established cardiovascular disease. Aspirin increases bleeding risk and can cause gastrointestinal ulceration.