Warfarin reversal

Background

1. Vitamin K
   1. Oral route is preferred over subcutaneous route: superior efficacy
   2. Intravenous route carries rare but serious risk of anaphylaxis
   3. Only give for patient with:
      1. Life-threatening bleeding
      2. INR >20
      3. Symptomatic patient poisoned by suicidal ingestion of warfarin or rodenticide

Excessive Anticoagulation

INR < 5 No Bleeding

1. Give lower dose of warfarin or omit one dose of warfarin
2. Resume warfarin at lower dose once INR therapeutic

INR 5-9 No Bleeding

1. Omit next 1-2 doses of warfarin
2. Vitamin K 1-2.5 mg oral: if patient at high risk for bleeding
   1. Age >75 years
   2. Concurrent antiplatelet drug use
   3. Polypharmacy
   4. Liver or kidney disease
   5. Alcoholism
   6. Recent surgery
   7. Trauma
3. Resume warfarin at lower dose once INR therapeutic

INR > 9 No Bleeding

1. Stop warfarin
2. Give Vitamin K 2.5-5 mg po: INR will decrease over 24-48 hours

Life-Threatening Bleed

1. Stop warfarin
2. Give 4-factor Prothrombin Complex Concentrate (PCC) or 3-factor PCC + recombinant factor VIIa
3. Give Vitamin K if PCC or factor VII not available
   1. 10mg slow IV push: may repeat in 12 hours if INR still elevated
   2. May induce unwanted thrombosis and/or overcorrection
4. Give IV Fresh Frozen Plasma (FFP) 10-15 mL/kg: for 70 kg patient, 3 units = 750 ml

See Also

• Warfarin (Coumadin)
• Dabigatran Reversal

Source

Tintinalli