Tranexamic acid mechanism — FRCA Primary MCQ

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ModeratePharmacologyTranexamic acid mechanismFRCA Primary

A trauma patient with major haemorrhage receives tranexamic acid early after arrival. Which mechanism best explains its benefit?

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Correct answer: A — Inhibition of plasminogen activation

Tranexamic acid is a lysine analogue that inhibits plasminogen binding and activation, reducing fibrinolysis. It does not activate antithrombin or directly inhibit thrombin; those mechanisms fit anticoagulants. Platelet cyclo-oxygenase stimulation is not relevant, and calcium chelation would worsen coagulation. Its clinical value depends on early use when hyperfibrinolysis is contributing to bleeding.

Reference: Peck, Hill & Williams Pharmacology for Anaesthesia and Intensive Care; CRASH-2 trial