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Warfarin Antidotes

  • Antidotes:

    • Vitamin K (phytonadione)

    • FFP (fresh frozen plasma)

    • Activated Prothrombin Complex Concentrate (found as FEIBA VH or anti-inhibitor coagulant complex in EMR)

    • Recombinant Factor VIIa (NovoSeven RT®)

  • Choice and dose is dependent on the clinical problem-no bleeding vs. significant bleeding and need for future warfarin therapy.

  • If patient requires rapid warfarin reversal but has no bleeding, insignificant bleeding or bruising:

    • Vitamin K 30 mcg/kg by slow IV infusion over 10-20 minutes (to avoid anaphylaxis). Max dose 2 mg.

      • This weight adjusted regimen is safer for pediatric patients than a universal dosage (i.e. 0.5-2mg) as recommended for adults. Even 0.5mg (sufficient for many adults) is likely to be too high for most young children. Seriously ill children with liver dysfunction may require more than a single dose. Oral vitamin K is effective in adults but the INR fall is slower than IV injection.

    • The preferred route is IV, but in a child with poor or no venous access, the PO or SQ route may be used, particularly if the INR is 6-10. The PO route is preferred.

    • The IM route is NOT recommended.

  • If patient has significant bleeding:

    • Not life threatening and will not cause morbidity:

      • Vitamin K 30 mcg/kg by slow IV infusion over 10-20 minutes (to avoid anaphylaxis). Max dose 2 mg.

      • Consider FFP 20 mL/kg IV.

    • Life threatening and will cause morbidity:

      • Vitamin K 30 mcg/kg IV by slow IV infusion over 10-20 minutes (to avoid anaphylaxis). Max dose 5mg.

      • And FFP 20 mL/kg IV.

      • Consider giving FEIBA VH 50 - 70 units/kg IV (first choice) or NovoSeven RT 90 micrograms/kg IV (alternate choice).

  • Safety of IV administration

    • The standard product for IV administration of Vitamin K at CMH is the 2mg/mL concentration, which is readily available in medication stations on every inpatient unit.

    • This dilute form (2mg/mL) along with slow IV infusion over 10 to 20 minutes may avoid anaphylaxis that has been associated with IV administration of vitamin K.

    • Where the concentrated 10mg/mL product is available, it must be diluted to 2mg/mL with D5W or NS prior to administration.


Ansell J, et al. Pharmacology and Management of the Vitamin K Antagonists: American College of Cheset Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 133 (6Suppl): 160S-198S, 2008 Jun.

Bolton-Maggs P , Brook L. The use of vitamin K for reversal of over-warfarinization in children. Br J Haematol 2002; 118:924.

David, M., et al. Warfarin Therapy in Children. Thrombosis Interest Group of Canada. May 2004. Accessed 10/21/08.

Horton, JD, et al. Warfarin Therapy: Evolving Strategies in Anticoagulation. American Family Physician; 1999 Feb; 59(3):635-646.

Lexi-Drugs Online/Pediatric Lexi-Drugs Online, Warfarin,, Copyright © 1978-2008 Lexi-Comp, Inc, Hudson, OH 44236

Monagle P. Chalmers E. Chan A. DeVeber G. Kirkham F. Massicotte P. Michelson AD. Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). [Journal Article] Chest. 133(6 Suppl):887S-968S, 2008 Jun.

Monagle P. Chan A. Massicotte P. Chalmers E. Michelson AD. Antithrombotic therapy in children: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. [Review] [487 refs] [Guideline. Journal Article. Practice Guideline. Review] Chest. 126(3 Suppl):645S-687S, 2004 Sep.

Roach ES. Golomb MR. Adams R. Biller J. Daniels S. Deveber G. Ferriero D. Jones BV. Kirkham FJ. Scott RM. Smith ER. American Heart Association Stroke Council. Council on Cardiovascular Disease in the Young. Management of stroke in infants and children: a scientific statement from a Special Writing Group of the American Heart Association Stroke Council and the Council on Cardiovascular Disease in the Young. [Journal Article] Stroke. 39(9):2644-91, 2008 Sep.

These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.