<prompt> Mechanism of action of AspirinInhibit PGI2 formationInhibit TXA2 formationStimulate TXA2 formationStimulate platelet aggregation  <response>: Ans. b Inhibit TXA2 formationRef KDT 6th ed. 609; Katzung 9th ed. 446Thromboxane helps in platelet aggregation. TXA2 formation is suppressed at very low doses of aspirin. Aspirin blocks thromboxane formation by inhibiting COX activity by enzyme COX1 and TX- synthase irreversibly. 