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Mx of excessive INR or bleeding on warfarin Rx


  • each unit rise in INR raises risk of bleeding 3.5-fold
  • INR levels > 4.5 in particular are associated with bleeding complications (6x risk cw < 4.5) and should be treated
  • ALL patients on warfarin who have a head injury should have a CT brain to exclude haemorrhage.
  • Mx should be individualised, with Rx depending on:
    • location & severity of bleeding
    • lab. test results,
    • risk of ceasing anticoagulant Rx
  • consider repeat INR 2-4hrly to identify rapid rises
  • NB. oral vitamin K is made from IV preparation and just given orally
  • if APTT prolonged and potentially life-threatening bleeding then give protamine
  • consider insertion of caval filter in pts with recent venous thromboembolism

Rx algorithm

  • (Cruickshank et al Emerg. Med. (2001) 13, 91-7)

major bleeding:

  • resuscitation
  • control bleeding
  • cease warfarin
  • seek senior advice (eg. haematologist)
  • vitamin K 5-10mg i.v.
  • FFP 150-300ml (if prothrombinex is unavailable, give 10-15ml/kg FFP)
  • Prothrombinex HT (clotting factor concentrate)
    • factor concentrates such as Prothrombinex HT are more effective than FFP at rapidly reversing coagulopathy
    • doses:
      • INR 2.0-3.9: 25 units/kg
      • INR 4.0-5.9: 35 units/kg
      • INR > 5.9: 50 units/kg

no bleeding or minor bleeding:

  • control bleeding
  • cease warfarin for 1-2 days
  • consider adjusting warfarin dose & look for contributing factors to toxicity
    • INR > 9:
      • vitamin K 2.5-5mg o or 1mg iv
      • consider prothrombinex-VF 25-50 units/kg iv +/- 150-300ml FFP if high risk of bleeding such as
        • age > 65yrs, high ethanol intake, risk of GIT bleed, uncontrolled hypertension, recent trauma, stroke
        • ref: therapeutic guidelines
      • re-check INR 6-12h
    • INR 5-9:
      • if bleeding risk is high, give vitamin K 1-2mg orally or 0.5-1mg slow iv
      • no FFP
      • re-check INR 12-24h
    • INR < 5:
      • no vit K if no bleeding (may consider iv or o vitamin K 0.5-1mg if minor bleeding)
      • re-check INR 12-24h

patient risk stratification for thrombosis if anticoagulation reversed:

high risk:

  • mechanical mitral valve
  • mechanical aortic valve with arrhythmia or PH thromboembolism

moderate risk:

  • AF with valvular heart disease, previous stroke or embolism
  • cardiomyopathy with heart failure, previous stroke or embolism
  • biological heart valves (1st 3months)
  • PH multiple PE/DVT
  • uncomplicated DVT (<2mths)
  • DVT/PE with lab-confirmed hypercoagulable blood
  • PH systemic arterial emboli
  • mechanical aortic valve without either arrhythmia or PH thromboembolism

low risk:

  • AF without either valvular heart disease, previous stroke or embolism
  • cardiomyopathy without either heart failure, previous stroke or embolism
  • biological heart valves (EXCEPT 1st 3months)
  • uncomplicated DVT (>2mths)
  • cerebrovascular disease
  • post AMI (mural thrombus prophylaxis)
  • vascular surgical prosthetic grafts
  • post vascular-stent insertion
odwarfarin.txt · Last modified: 2014/05/11 10:26 by

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