What is the best approach to transition a patient with atrial fibrillation or venous thromboembolism from Xarelto (rivaroxaban) to warfarin?

Transitioning from Xarelto (Rivaroxaban) to Warfarin

When switching from rivaroxaban to warfarin, you must continue rivaroxaban for at least 2 days after starting warfarin, then check INR before the next rivaroxaban dose, and continue both drugs until INR reaches ≥2.0 (for pediatric patients) or the therapeutic range of 2.0-3.0 (for adults). 1

Transition Protocol for Adults

The FDA-approved rivaroxaban label provides limited guidance for adults, noting that "no clinical trial data are available to guide converting patients from XARELTO to warfarin" and that "XARELTO affects INR, so INR measurements made during coadministration with warfarin may not be useful for determining the appropriate dose of warfarin." 1

Recommended Adult Approach:

One validated approach is to discontinue rivaroxaban and begin both a parenteral anticoagulant (such as low molecular weight heparin or unfractionated heparin) and warfarin simultaneously at the time the next dose of rivaroxaban would have been taken. 1 This bridging strategy ensures continuous anticoagulation during the transition period when warfarin has not yet reached therapeutic levels.

• Continue the parenteral anticoagulant until INR reaches the therapeutic range of 2.0-3.0 1
• For patients requiring vitamin K antagonist therapy after PCI or in high bleeding risk scenarios, aim for the lower end of the target INR range (2.0-2.5) with more frequent INR monitoring 2

Transition Protocol for Pediatric Patients

For pediatric patients, the FDA label provides more specific guidance: continue rivaroxaban for at least 2 days after the first dose of warfarin. 1

Step-by-Step Pediatric Protocol:

1. Start warfarin while continuing rivaroxaban 1
2. After 2 days of co-administration, obtain an INR prior to the next scheduled rivaroxaban dose 1
3. Continue both medications until INR is ≥2.0 1
4. Once rivaroxaban is discontinued, INR testing may be done reliably 24 hours after the last dose 1

Critical Timing Considerations

• Rivaroxaban has a short half-life (7-11 hours) and time to peak concentration of 2-4 hours 2
• The anticoagulant effect of rivaroxaban dissipates relatively quickly after discontinuation, creating a window of vulnerability if warfarin is not yet therapeutic 3
• INR measurements during co-administration are affected by rivaroxaban and may not accurately reflect warfarin's effect alone 1

Special Clinical Scenarios

High Thrombotic Risk Patients

For patients at very high risk of recurrent VTE (within 3 months of acute VTE or other thrombophilic states), bridging with low molecular weight heparin is appropriate despite increased bleeding risk. 2 For all other patients, the direct transition approach without bridging may be undertaken. 2

Renal Impairment

• Rivaroxaban is contraindicated in severe renal insufficiency (CrCl <30 mL/min) for VTE indication 2
• An unusual scenario warranting transition to warfarin would be a patient on therapeutic rivaroxaban for VTE who develops significant renal dysfunction precluding further DOAC use 2
• Monitor renal function closely during transition, as changes can affect both rivaroxaban clearance and warfarin dosing requirements 3, 4

Monitoring During Transition

INR Monitoring Strategy:

• Check INR before starting the transition to establish baseline 2
• During co-administration, INR values are artificially elevated by rivaroxaban and do not reliably reflect warfarin effect 1
• Wait 24 hours after the last rivaroxaban dose before obtaining a reliable INR to guide warfarin dosing 1
• Once on warfarin alone, check INR at least weekly during initiation, then at least monthly when stable 2

Common Pitfalls to Avoid

Do not rely on INR measurements obtained while rivaroxaban and warfarin are being co-administered to guide warfarin dosing, as rivaroxaban artificially elevates INR. 1 This is a critical error that can lead to either under-anticoagulation (if warfarin dose is held due to falsely elevated INR) or over-anticoagulation (if warfarin is dosed based on the combined effect).

Do not simply stop rivaroxaban and start warfarin without bridging or overlap in adults, as this creates a dangerous gap in anticoagulation coverage. 1 Warfarin requires several days to achieve therapeutic anticoagulation due to its mechanism of depleting vitamin K-dependent clotting factors.

Do not use the adult transition protocol for pediatric patients. 1 The pediatric protocol specifically requires continuation of rivaroxaban during warfarin initiation, whereas the adult protocol typically uses parenteral bridging.

Avoid nonsteroidal anti-inflammatory drugs and antiplatelet agents during the transition unless specifically indicated, as they increase bleeding risk. 2 Consider proton pump inhibitor therapy if the patient requires concomitant antiplatelet therapy. 2

Do not forget to counsel patients about the fundamental differences between rivaroxaban and warfarin management. 3 Unlike rivaroxaban's fixed dosing, warfarin requires dietary vitamin K consistency, frequent monitoring, and dose adjustments. 2, 4