Managing atrial fibrillation using anticoagulants is a proactive approach to preventing stroke. Traditionally, AF required treatment with warfarin but, increasingly, direct-acting oral anticoagulants (DOACs) are being used. In clinical trials of patients with non-valvular AF, DOACs have been shown to be at least as effective as warfarin. As a result, there are currently four DOACs – apixaban, dabigatran, edoxaban and rivaroxaban – available for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation. 

Unlike warfarin, DOACs have fixed once- or twice-a-day dosing regimens without the requirement for regular blood testing to adjust levels. However, DOACs are renally excreted so choice of dosage, and whether a DOAC can be prescribed, requires ongoing assessment of the patient’s renal function. 

Warfarin should be used:

• If DOACs are contraindicated, for example, patients with mechanical heart valves, patients with moderate to severe mitral stenosis or patients with antiphospholipid syndrome
• In severe renal impairment 
• At extremes of body weight – there is less information available on the efficacy and/or safety of DOACs in patients with low (less than 50kg) or high (more than 120kg) body weight
• If drug interactions are likely to have a significant effect on DOAC levels.