This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antiplatelets and Fibrinolytics, Subject name: Pharmacology
Mechanism of action of Aspirin in MI is : 
Select and explain. 
A. Thromboxane A2 synthesis inhibition, B. Thromboxane A2 synthesis stimulation, C. Antagonist of adenosine, D. Stimulation of PGF2 synthesis
A: Thromboxane A2 synthesis inhibition
Answer: A: Thromboxane A2 synthesis inhibition 
Explanation: Ans is 'a' Thromboxane A2 synthesis inhibition (Ref Goodman Gilman, 10/e, p. 1534; KDT 5/e p. 572).Aspirin is used in MI because of its antiplatelet action.Antiplatelet action of aspirin: Aspirin blocks the production of thromboxane A2 by inactivating the enzyme cyclooxygenase. Cyclooxygenase is an enzyme that produces cyclic endoperoxide precursor of thromboxane A2.