Fig. 3: Mechanism of action of warfarin.

Warfarin inhibits the formation of the active form of vitamin K. Warfarin—clinically available as an equal mixture of R and S enantiomers—inhibits vitamin K oxidoreductase complex 1 (VKORC1) and, therefore, prevents the reduction of vitamin K1 to vitamin KH2. KH2 is necessary for γ-glutamyl carboxylase (GGCX) expression and activation of clotting factors II, VII, IX, and X (modified from ref. 101). Figure created with Bio Render.com.