Warfarin reversal

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Background

  • For supratheraputic INR on warfarin
  • Intracranial hemorrhage is significantly increased with an INR > 4.0[1]

Target INR

  • Vascular thrombosis (DVT, PE): 2.0-3.0
  • Most mechanical heart valves: 3.0-4.5
    • Bileaflet mechanical aortic heart valves: 2.5-3.5)

Risk Factors for INR > 6.0[2]

Risk Factor Odds Ratio
Malignancy 16.4
Tylenol Intake > 9100 mg/week 10
New Medication 8.5
Increased Warfarin Intake 8.1
Tylenol Intake 4550 mg - 9099 mg/week 6.9
Decrease Vitamin K intake 3.6
Acute Diarrheal Illness 3.5
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Algorithm for the management of supratherapeutic INR

Treatment based on INR[3]

INR 4.5-10 No Bleeding

  1. Hold Warfarin
  2. Resume Warfarin at lower dose once INR therapeutic
  3. Not recommended to give Vitamin K

INR >10 No Bleeding

  1. Hold Warfarin
  2. Vitamin K 2.5mg oral

Major Bleeding

  1. Stop warfarin
  2. Give Vitamin K 5-10mg IV INR will decrease over 24-48 hours (small risk of anaphylaxis with IV Vitamin K)
  3. Give 4 Factor prothrombin complex concentrate (PCC)

Consult cardiology in conjunction with hematology if patient has prosthetic valve

See Also

Video

References

  1. Hylek EM, Singer DE. Risk factors for intracranial hemorrhage in outpatients taking warfarin. Ann Intern Med.1994;120:897-902.
  2. Hylek, E et al. Acetaminophen and Other Risk Factors for Excessive Warfarin Anticoagulation. JAMA. 1998;279(9):657-662 PDF
  3. Holbrook A, et al; American College of Chest Physicians. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb;141 PDF