This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'All are true about warfarin except - \nSelect and explain. \nA. It causes inhibition of vitamin K dependent doting factors, B. T1/2 36 hours, C. Crosses placenta, D. Dose is increased in liver disease', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Dose is increased in liver disease 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 T1/2 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.", 'role': 'assistant'}]