Curriculum · Hematology
Warfarin over-anticoagulation and reversal
What it is
Warfarin works through the vitamin K dependent coagulation factors, which are factors II, VII, IX and X together with protein C and protein S. It inhibits the vitamin K epoxide reductase enzyme and so depletes those factors. Its onset of action is 24 to 72 hours, with a peak at 5 to 7 days, so it needs bridging. The half-life of warfarin is 40 hours.
How it is diagnosed
Monitoring of warfarin is by the INR.