<prompt> All are true about warfarin exceptIt inhibits the activation of vitamin K dependent clotting factorsIts half life is 36hrsIt can cross placentaIts dose is increased in liver disease  <response>: Refer Katzung 11e p595 Warfarin is an oral anticoagulant that acts by inhibiting the gamma carboxylation of glutamate residues in vitamin K dependent clotting factors It has a long half life It readily crosses the placenta Liver disease reduces the synthesis of clotting factors thus increases the effect of warfarin 