Warfarin is used for preventing and treating venous or arterial thrombosis and embolism.
Warfarin works by blocking the gamma-carboxylation of glutamic acid residues of Vitamin K−dependent coagulation factors. This blockage inhibits synthesis of Vitamin K−dependent coagulation factors, resulting in decreased biological activity of factors II, VII, IX, X and protein C and protein S; with prolongation of the international normalised ratio (INR).
Warfarin is a potentially hazardous drug that causes major bleeding, including intracranial haemorrhage. Patients on long-term therapy have a risk of 1%-3% per year for haemorrhage leading to hospitalisation or death.(1)
Recently, the PBS has provided subsidy to new oral anticoagulants (NOAC) which may be used alternatively to warfarin.
Reference
- Tadros Rami, Shakib, Sepehr. Warfarin indications, risks and drug interactions. AFP 2010; 39(7):476-479.