Acute coronary syndrome: guidelines for antiplatelets and anticoagulants

Warfarin, aspirin, clopidogrel, prasugrel, ticagrelor, DOAC, dalteparin and fondaparinux

Direct oral anticoagulants (DOACs) - Apixaban, Edoxaban, Rivaroxaban and Dabigatran

*If Aspirin 300mg has been given by SAS (Scottish Ambulance Service) do not repeat

If a patient is admitted with ACS and is already taking warfarin and INR is therapeutic:

• do not give dalteparin or fondaparinux
• give admission dose of aspirin 300mg* and clopidogrel 300mg if troponin positive
• give admission dose of aspirin 300mg* but not clopidogrel if troponin negative
• early senior decision as to whether to continue aspirin and/or add clopidogrel

If a patient is admitted with ACS and is already taking warfarin and INR is sub-therapeutic and there is a definite ongoing indication for warfarin:

• start dalteparin treatment dose banded according to patient's weight
• give admission dose of aspirin 300mg* and clopidogrel 300mg if troponin positive
• give admission dose of aspirin 300mg* but not clopidogrel if troponin negative
• early senior decision as to whether to continue aspirin and/or add clopidogrel

If a patient is admitted with ACS and is already taking warfarin and INR is supra-therapeutic more than 4:

• senior review before additional antiplatelet therapy

If a patient is admitted with ACS and warfarin needs to be stopped temporarily (e.g. if patient needs angio):

• if need for ongoing anti-coagulation, start treatment dose dalteparin
• if patient undergoing angiography with view to PCI, start aspirin 75mg once daily and
  clopidogrel 300mg loading and 75mg once daily thereafter in addition to dalteparin
• if not for angiography/PCI, senior decision whether to give antiplatelet treatment

If patient is already on anti-platelet therapy and needs to start warfarin:

• start warfarin and treatment dose dalteparin until INR therapeutic
• senior review whether need for concomitant anti-platelet therapy – indication for
  concomitant therapy must be documented on warfarin prescription form

If patient is admitted with ACS and is taking a DOAC:

• do not give dalteparin or fondaparinux
• give admission dose of aspirin 300mg* and clopidogrel 300mg if troponin positive
• give admission dose of aspirin 300mg* but not clopidogrel if troponin negative
• ensure senior review before next dose of DOAC

Notes:

• all patients on dual antiplatelets/anticoagulant therapy should be considered for PPI
• if in doubt about combination therapy ask
• review need for all these agents regularly