Aspirin and carbasalate calcium


Aspirin and its calcium salt carbasalate calcium inhibit cyclo-oxygenase, an enzyme essential for the conversion of arachidonic acid into thromboxane A2. Thromboxane A2causes vasoconstriction and platelet activation. Aspirin therefore causes diminished platelet activation.

Aspirin binds irreversibly to cyclo-oxygenase and since platelets do not synthesize proteins (enzymes) by themselves, the effect of aspirin lasts for the life of the platelet (7-10 days).
Aspirin is indicated for the secondary prevention of arterial thromboembolism (after a cerebral infarction, TIA, myocardial infarction, unstable angina). Adverse effects of aspirin are increased bleeding (especially gastro-intestinal).
See also platelet aggregation inhibitors and NSAIDs in the pain section.


Mr K (58 years old and 90 kg) has gone through a mild myocardial infarction. His medical history mentions frequent episodes of ulcerations in the stomach and diabetes. How would you prophylax for reinfarction? 


What is NOT true about thromboxane A2 (TXA2):