Transitioning from Apixaban to Warfarin

Introduction to Transition Protocol

The National Comprehensive Cancer Network recommends starting warfarin at the usual initial dose (typically 5 mg daily, or 2.5 mg if liver disease or interacting medications present) 1
The National Comprehensive Cancer Network suggests simultaneously beginning a parenteral anticoagulant at the time of the next scheduled apixaban dose, with options including LMWH (dalteparin 200 units/kg SC daily or enoxaparin 1 mg/kg SC every 12 hours) or UFH (IV: 80 units/kg bolus, then 18 units/kg/hour, targeting aPTT 2-2.5× control, or SC: 333 units/kg load, then 250 units/kg every 12 hours) 1, 2

The American College of Cardiology recommends checking INR daily during the transition 3
The National Comprehensive Cancer Network advises continuing both warfarin and the parenteral anticoagulant for at least 5 days, and stopping the parenteral anticoagulant only when both criteria are met: at least 5 days of overlap therapy completed and INR ≥2.0 for at least 24 hours (target INR 2.0-3.0) 1, 4

For patients at very high thrombotic risk, the National Comprehensive Cancer Network recommends ensuring there is absolutely no gap in anticoagulation coverage by starting the parenteral agent at the exact time the next apixaban dose would have been due 2
The National Comprehensive Cancer Network suggests obtaining baseline CBC, PT, aPTT, and renal/hepatic function before transition, and assessing for concomitant antiplatelet agents or NSAIDs that increase bleeding risk 2

The National Comprehensive Cancer Network recommends continuing warfarin for the duration appropriate to the indication (minimum 3 months for VTE, indefinite for atrial fibrillation or recurrent VTE) 2, 4

The American Heart Association recommends monitoring renal function during transition from apixaban to warfarin, as changes in kidney function affect both apixaban clearance and warfarin dosing requirements 5