All about warfarin are true EXCEPT:

Contraindicated in hepatic failure REF: Goodman and Gillman's 11th edition, page 955-956 Warfarin: Therapeutic doses of warfarin decrease by 30-50% the total amount of each vitamin K-dependent coagulation factor made by the liver The usual adult dose of warfarin (COUMADIN) is 5 mg/day for 2-4 days, followed by 2-10 mg/day as indicated by measurements of the INR The bioavailability of warfarin is nearly complete when the drug is administered orally, intravenously, or rectally. Warfarin is almost completely (99%) bound to plasma proteins, principally albumin, and the drug distributes rapidly into a volume equivalent to the albumin space The t1/2 ranges from 25 to 60 hours (means 40 hours); the duration of action of warfarin is 2-5 days. Bleeding is the major toxicity of oral anticoagulant drugs. Crosses placenta and causes fetal malformations and aboion if given during pregnancy (see APPENDIX-32)