Transitioning from Apixaban to Warfarin
When switching from apixaban to warfarin, discontinue apixaban and simultaneously begin both a parenteral anticoagulant (such as LMWH or UFH) and warfarin at the time the next dose of apixaban would have been taken, then discontinue the parenteral anticoagulant when INR reaches the therapeutic range of 2.0-3.0. 1
Recommended Protocol
Step-by-Step Transition Process
Discontinue apixaban at the scheduled time of the last dose 1
Immediately initiate warfarin at the time the next apixaban dose would have been taken, typically starting with 5 mg daily (or 2.5 mg daily if the patient has liver disease or is taking interacting medications) 2
Simultaneously start parenteral anticoagulation with either:
Continue the parenteral anticoagulant alongside warfarin until INR reaches an acceptable therapeutic range (typically 2.0-3.0) 1
Discontinue parenteral anticoagulation once INR is therapeutic and stable 1
Critical Rationale
Why bridging is necessary: Apixaban affects INR measurements, making initial INR values during the transition unreliable for determining appropriate warfarin dosing 1. The parenteral anticoagulant provides continuous anticoagulation coverage during the 4-5 days required for warfarin to reach therapeutic effect 2.
Duration of overlap: Parenteral anticoagulation should continue for at least 4-5 days alongside warfarin until the INR stabilizes in the therapeutic range 2. This ensures no gap in anticoagulation protection during the transition period.
Important Considerations
Monitoring Requirements
Do not rely on initial INR measurements during the first few days of transition, as apixaban's residual effect will interfere with accurate INR determination 1
Check INR regularly once warfarin is initiated, but understand that therapeutic INR values will only be meaningful after apixaban has been fully cleared (approximately 24-48 hours after the last dose, depending on renal function) 2
Target INR of 2.0-3.0 for most indications, with time in therapeutic range (TTR) ideally >70% once stable 2
Common Pitfalls to Avoid
Never stop apixaban without immediately starting bridging anticoagulation and warfarin - this creates a dangerous gap in anticoagulation coverage, particularly in high-risk patients 1
Do not attempt to use INR alone to guide the transition in the first 48 hours, as apixaban will falsely affect these values 1
Avoid premature discontinuation of parenteral anticoagulation before achieving stable therapeutic INR on at least two consecutive measurements 2
Patient-Specific Factors
High thrombotic risk patients (recent VTE within 3 months, mechanical heart valves, or thrombophilic states) require particularly careful bridging without any gaps in anticoagulation 2
Renal dysfunction: Patients with impaired renal function may have prolonged apixaban clearance, potentially requiring extended bridging duration 2
Bleeding risk: While bridging increases bleeding risk, it remains necessary for most patients to prevent thrombotic events during the transition 2