Warfarin reversal

Background

1. Goals:
   1. Identify and attenuate the cause of bleeding
   2. Lower the INR
2. PO route for vit K is preferred due to superior efficacy compared to subq route

Excessive Anticoagulation

INR < 5 No Bleeding

1. Lower dose or omit one dose
2. Resume at lower dose once INR therapeutic

INR 5-9 No Bleeding

1. Hold next 1-2 doses
2. Vit K 1-2.5mg po (only if pt is at high risk for bleeding)
   1. Age >75yr
   2. Concurrent antiplatelet drug use
   3. Polypharmacy
   4. Liver or renal disease
   5. Alcoholism
   6. Recent surgery
   7. Trauma
3. Resume at lower dose once INR therapeutic

INR ≥ 9 No Bleeding

1. Hold warfarin
2. Vit K 2.5-5mg po
3. INR will decrease in 24-48h

Specific Reversal Reasons

Undergoing Surgery

1. Omit dose
2. Give Vit K 2-4mg po
3. Drop in INR will occur in 24h
4. If INR still high may give additional Vit K 1-2mg po

Life-Threatening Bleeding

1. Hold warfarin
2. Vitamin K
   1. 10mg slow IV push (may repeat in 12hr if INR still elevated)
   2. May induce unwanted thrombosis and/or overcorrection
3. FFP
   1. Administer 10-15mL/kg (typically 3-4units)

Treatment

1. Oral vitamin K is available in tablet and solution formulations

See Also

Warfarin (Coumadin)

Source

Ansell J, Hirsh J, Poller L et al. The Pharmacology and Management of the Vitamin K Antagonists. CHEST. 126(3S):204S-233S.