How to switch a patient from Xarelto (rivaroxaban) to warfarin?

Switching from Rivaroxaban (Xarelto) to Warfarin

When switching a patient from rivaroxaban to warfarin, discontinue rivaroxaban and begin both a parenteral anticoagulant (such as heparin) and warfarin simultaneously at the time the next rivaroxaban dose would have been taken, continuing this overlap until the INR reaches ≥2.0. 1

Step-by-Step Protocol

For Adult Patients:

1. Initial Assessment

   • Determine the indication for anticoagulation and confirm the need to switch
   • Check baseline labs including complete blood count, renal function, and liver function
   • Assess bleeding risk factors

2. Transition Process

   • Day 1: Discontinue rivaroxaban
   • Same day: Begin both warfarin and a parenteral anticoagulant (unfractionated heparin or LMWH) at the time the next rivaroxaban dose would have been taken 1
   • Important: Do not rely on INR measurements during this transition period as rivaroxaban affects INR values, making them unreliable for warfarin dosing 1

3. Monitoring During Transition

   • Continue parenteral anticoagulant and warfarin together
   • Check INR daily, preferably at the same time each day
   • Continue parenteral anticoagulant until INR reaches ≥2.0 (or target range based on indication)
   • Once target INR is achieved, discontinue parenteral anticoagulant

4. Post-Transition Monitoring

   • After discontinuing rivaroxaban, reliable INR testing can be done 24 hours after the last dose 1
   • Monitor INR frequently during the first week (2-3 times), then weekly until stable
   • Once stable, monitor INR every 2-4 weeks or as clinically indicated

For Pediatric Patients:

For pediatric patients, the FDA label provides specific guidance:

• Continue rivaroxaban for at least 2 days after the first dose of warfarin
• After 2 days of co-administration, check INR prior to the next scheduled rivaroxaban dose
• Continue co-administration until INR is ≥2.0
• Once rivaroxaban is discontinued, INR testing becomes reliable 24 hours after the last dose 1

Special Considerations

High-Risk Patients

For patients at high risk of thromboembolism during transition:

• Consider using therapeutic doses of heparin (15,000 U every 12 hours subcutaneously) or LMWH (100 U/kg every 12 hours subcutaneously) 2
• For critical situations requiring continuous anticoagulation, consider hospital admission for continuous IV heparin (1300 U/h) 2

Patients with Renal Impairment

• Patients with renal impairment may have prolonged rivaroxaban clearance
• More frequent INR monitoring may be necessary
• Consider lower initial warfarin doses

Common Pitfalls to Avoid

1. Inadequate Bridging: Failing to use a parenteral anticoagulant during transition can leave patients unprotected
2. Relying on INR During Overlap: Rivaroxaban affects INR values, making them unreliable for warfarin dosing during co-administration
3. Premature Discontinuation: Stopping the parenteral anticoagulant before therapeutic INR is achieved
4. Inadequate Monitoring: Not checking INR frequently enough during the transition period
5. Overlooking Drug Interactions: Not accounting for medications that may interact with warfarin

Clinical Rationale

The need for overlapping parenteral anticoagulation when switching from rivaroxaban to warfarin stems from:

1. The immediate offset of rivaroxaban's anticoagulant effect after discontinuation
2. The delayed onset of warfarin's therapeutic effect (typically 5-7 days)
3. The unreliability of INR measurements during rivaroxaban therapy

This approach ensures continuous anticoagulation protection during the transition period, minimizing the risk of thrombotic events while managing bleeding risk.