Impairs Vitamin K-dependent carboxylation of factors II, VII, IX, X, C, S and Z.
Anticoagulation in atrial fibrillation
Reduces risk of embolic stroke in atrial fibrillation. Goal INR 2-3 in patients with CHADS2 >=2.
Secondary prevention of MI in patients with known CAD
Typically preceded by heparin for 3 or 4 days to allow the warfarin to become therapeutic and prevent initial hypercoagulability due to decrease in protein C
1 tab, 2-10 mg PO daily, start low and go slow, follow INR
Urine T1/2 20-60 hrs, highly variable
Teratogenic. Pregnancy class X. Period of sensitivity is 4-6 weeks.
Fetal Warfarin syndrome includes many deformities including heart defects.
Can see short-term hypercoagulability due to decrease of Protein C, which is anticoagulating -> develop thrombotic occlusion of microvasculature -> "warfarin-induced skin necrosis"