<prompt> All about warfarin are true EXCEPT?Half-life is 36 hoursCrosses placentaContraindicated in hepatic failureInhibits all vitamin K dependent clotting factors  <response>: Ans. is c i.e., Contraindicated in hepatic failure o Liver disease requires dose reduction, but is not a contraindication. Effect of liver disease on warfarin o In liver diseases the dose of oral anticoagulats needs to be decreased because in liver disease the hepatic synthesis of clotting factors is reduced. o Thus there is already a deficiency of clotting factors i.e. there is preexisting anticoagulant state. o Administration of warfarin is this state increases the risk of bleeding. About other options o Warfarin is an indirectly acting anticoagulant, i.e. it inhibits vitamin K which in turn inhibits coagulation factors. o T12 of warfarin is 36 hrs. o Warfarin can cross placenta and cause fetal warfarin syndrome. Therefore it is contraindicated pregnancy. Patient is switched to heparin from warfarin during pregnancy. 