Warfarin reversal

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
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

[[Category:WikEM]]

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