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Warfarin reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis

Ross I Baker, Paul B Coughlin, Hatem H Salem, Alex S Gallus, Paul L Harper and Erica M Wood
Med J Aust 2004; 181 (9): 492-497.

Summary

  • For most warfarin indications, the target maintenance international normalised ratio (INR) is 2–3.

  • Risk factors for bleeding complications with warfarin use include age, history of past bleeding and specific comorbid conditions.

  • To reverse the effects of warfarin, vitamin K1 can be given. Immediate reversal is achieved with a prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP). Vitamin K1 is essential for sustaining the reversal achieved by PCC and FFP.

  • When oral vitamin K1 is used for warfarin reversal, the injectable formulation of vitamin K1 is preferable to tablets because of its flexible dosing; this formulation can be given orally or injected.

  • To temporarily reverse the effect of warfarin when there is a need to continue warfarin therapy, vitamin K1 should be given in a dose that will quickly lower the INR to a safe, but not subtherapeutic, range and will not cause resistance once warfarin is reinstated.

  • Prothrombinex-HT is the only PCC approved in Australia and New Zealand for warfarin reversal. It contains factors II, IX and X, and low levels of factor VII. FFP should be added to Prothrombinex-HT as a source of factor VII when used for warfarin reversal.

  • Simple dental or dermatological procedures may not require interruption to warfarin therapy.

  • If necessary, warfarin therapy can be withheld 5 days before elective surgery, when the INR usually falls to below 1.5 and surgery can be conducted safely.

  • Bridging anticoagulation therapy for patients at high risk for thromboembolism should be undertaken in consultation with the relevant experts.

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  • Ross I Baker1
  • Paul B Coughlin2
  • Hatem H Salem3
  • Alex S Gallus4
  • Paul L Harper5
  • Erica M Wood6

  • 1 Thrombosis and Haemophilia Service, Royal Perth Hospital, Perth, WA.
  • 2 Monash University, Box Hill Hospital, Box Hill, VIC.
  • 3 SouthPath, Flinders Medical Centre, Bedford Park, SA.
  • 4 Auckland City Hospital, Auckland, New Zealand.
  • 5 Australian Red Cross Blood Service, Southbank, VIC.

Correspondence: 

Acknowledgements: 

The Warfarin Reversal Consensus Group thanks Lucy Race and Kim Magner, of Discovery International Australia, for their assistance in the writing of the manuscript.

Competing interests:

An unrestricted educational grant from CSL Bioplasma enabled the Warfarin Reversal Consensus Group (WRCG) to meet, develop and write these guidelines. As part of this grant, a number of members of the WRCG received paid honoraria. In addition, CSL Bioplasma and the Australian Red Cross Blood Service were consulted for technical information relating to Prothrombinex-HT and fresh frozen plasma.

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