What is the protocol for transitioning from Xarelto (rivaroxaban) to heparin?

Transitioning from Xarelto (Rivaroxaban) to Heparin

When transitioning from Xarelto to heparin, discontinue Xarelto and start heparin (either unfractionated heparin or low-molecular-weight heparin) at the time the next scheduled dose of Xarelto would have been due, with no overlap or gap in anticoagulation. 1

Standard Transition Protocol

Timing of the Switch

• Stop Xarelto and initiate heparin at the exact time the next Xarelto dose would have been scheduled to ensure continuous anticoagulation coverage without gaps 1
• For unfractionated heparin (UFH) given by continuous infusion, start the infusion at the time of the next scheduled Xarelto dose 1
• For low-molecular-weight heparin (LMWH), administer the first subcutaneous dose when the next Xarelto dose would have been due 1

Heparin Dosing Options

Unfractionated Heparin (UFH):

• Intravenous bolus: 80 units/kg, followed by continuous infusion at 18 units/kg/hour, targeting aPTT 2-2.5× control or heparin level 0.3-0.7 U/mL by chromogenic anti-Xa assay 2
• Subcutaneous: 333 units/kg loading dose, then 250 units/kg every 12 hours 2

Low-Molecular-Weight Heparin (LMWH):

• Enoxaparin: 1 mg/kg subcutaneously every 12 hours (or 1.5 mg/kg once daily) 2
• Dalteparin: 200 units/kg subcutaneously once daily 2
• Tinzaparin: 175 units/kg subcutaneously once daily 2

Critical Monitoring Considerations

Interference from Residual Rivaroxaban

• Rivaroxaban can interfere with heparin anti-Xa monitoring for up to 3 days after discontinuation, potentially causing overestimation of UFH anticoagulant effect 2
• Even rivaroxaban concentrations below 30 ng/mL can cause interference with heparin anti-Xa assays and may persist for several days 2
• If using anti-Xa monitoring for UFH, expect more frequent down-titrations in the first 6 hours and up-titrations after 36 hours due to residual rivaroxaban activity 3

Monitoring Strategy

• For UFH infusions, aPTT monitoring may be preferable to anti-Xa assays during the first 24-48 hours to avoid interference from residual rivaroxaban 2, 3
• If anti-Xa monitoring is used, be aware that results may overestimate actual heparin levels initially 2
• Obtain baseline heparin anti-Xa activity before starting heparin to identify patients with significant residual rivaroxaban concentrations 3
• Monitor for both bleeding and thrombotic complications during the transition period 3

Special Clinical Scenarios

Perioperative Transitions

• For procedures requiring heparin anticoagulation, stop Xarelto at least 24 hours before the procedure to reduce bleeding risk 1
• The timing may need adjustment based on renal function, as rivaroxaban is partially renally cleared 2
• Restart anticoagulation as soon as adequate hemostasis is established postoperatively 1

High Thrombotic Risk Patients

• Ensure absolutely no gap in anticoagulation by starting heparin precisely when the next Xarelto dose would be due 4
• Consider checking baseline coagulation parameters (CBC, PT, aPTT) and renal/hepatic function before transition 4
• Assess for concomitant antiplatelet agents or NSAIDs that increase bleeding risk 4

Renal Impairment

• Patients with renal dysfunction may have prolonged rivaroxaban half-life, extending the period of potential interference with heparin monitoring 2
• Adjust heparin dosing based on renal function, particularly for LMWH which requires dose reduction or avoidance when creatinine clearance is below 30 mL/minute 2

Common Pitfalls to Avoid

• Do not overlap Xarelto and heparin - this increases bleeding risk without improving anticoagulation 1
• Do not create gaps in anticoagulation - start heparin at the scheduled time of the next Xarelto dose 1
• Do not rely solely on anti-Xa monitoring in the first 24-48 hours if the patient recently took rivaroxaban, as residual drug levels will falsely elevate results 2, 3
• Do not assume therapeutic heparin levels are achieved immediately - close monitoring is essential during the transition period 3