Oral anticoagulation with warfarin

28th July 2011 by Louise Hudman

Most of this is managed in secondary care and anticoagulation clinics. It is a useful resource if you’ve got a specific query. Some of the advice may alter what we do:

Management of high INRs in non-bleeding patients

  • Take into account risk factors for bleeding, when deciding what to do (eg age / uncontrolled hypertension / diabetes / renal or liver failure / previous bleeds / antiplatelet treatment).
  • The BNF advice broadly follows this guidance, so it seems reasonable to follow that. Remember that you have to use iv Vitamin K, given orally (BNF advice).

Head Injuries in patients on Warfarin:

  • Check the INR, however minor the injury.
  • If there is any loss of consciousness, amnesia or a reduced GCS, a CT is needed.
  • If there are facial or scalp lacerations, bruising, or persistent headache, this would normally warrant a CT scan.
  • After head injury, there is a higher risk of a bleed for 4/52, so keep the INR as close to 2 as possible.

Using Warfarin with aspirin and clopidogrel

  • Basically triple therapy or dual therapy with clopidogrel and warfarin increases bleeding risk a lot, compared to single therapy or aspirin with warfarin. If dual therapy is needed, aspirin is therefore preferred. Time spent on combination therapy should be at the shortest duration possible.

On antiplatelet therapy and develop a need for warfarin:

  • AF / stable CVD – eg > 12m post MI. There is no benefit from extra aspirin so stop it.
  • PVD / CVA stop aspirin.
  • Stent, cardiology should decide here, as generally triple therapy is better.
  • If < 12m post ACS, continue aspirin until 12m, unless there is a high bleeding risk.

On warfarin and develop a need for antiplatelets:

  • Review the need for warfarin and stop it if possible (eg VTE after 3m).
  • ACS and no stent – triple therapy for 4/52, then aspirin + warfarin.
  • ACS with a stent – decision will be made by cardiology


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