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Warfarin

Starting treatment
Indications
Dosing and monitoring
Complications
Follow-up
Complications

Major bleed

Consider giving 0.5 mg to 2.0 mg vitamin K iv a (clinical response takes 4 to 6 hours) c  

Why?

  • Few patients on steady-state warfarin dosing have normal INRs within 3 days of stopping. Most have normal INRs within 8 days. The INR declines more slowly in older patients. c
  • Vitamin K lowers INR effectively c
  • Intravenous vitamin K leads to a faster response than subcutaneous. a

Expiry date: May 2003
Levels of Evidence used in grading these guides

With thanks to Drs. David Keeling, John Reynolds, David Sackett, Sharon Straus and Alan Townsend 
 for use of their anticoagulation guide on which this one is based.

Author   CM   Ball
Reviewer   A   Gallus
CAT Writer   CM   Ball