From the FDA Drug Label
Switching from Anticoagulants other than Warfarin to XARELTO - For adult and pediatric patients currently receiving an anticoagulant other than warfarin, start XARELTO 0 to 2 hours prior to the next scheduled administration of the drug (e.g., low molecular weight heparin or non-warfarin oral anticoagulant) and omit administration of the other anticoagulant. For unfractionated heparin being administered by continuous infusion, stop the infusion and start XARELTO at the same time.
The patient can start rivaroxaban 0 to 2 hours prior to the next scheduled administration of heparin, and the loading dose is not explicitly mentioned to be discounted in this scenario. No discount to the loading dose is specified. Therefore, the loading dose should not be discounted when switching from heparin to rivaroxaban 1.
From the Research
When transitioning from therapeutic heparin to rivaroxaban in a patient with pulmonary embolism, the loading dose of rivaroxaban should still be administered. The recommended approach is to discontinue the heparin infusion and immediately start rivaroxaban at the loading dose of 15 mg twice daily for the first 21 days, followed by 20 mg once daily thereafter. For patients on subcutaneous low molecular weight heparin, rivaroxaban should be initiated 0-2 hours before the next scheduled heparin dose. The loading dose is essential because it rapidly achieves therapeutic anticoagulation levels needed to treat the acute phase of pulmonary embolism. Skipping the loading dose could leave the patient with insufficient anticoagulation during this critical period. The pharmacokinetics of rivaroxaban differ from heparin, with rivaroxaban directly inhibiting factor Xa while heparin works through antithrombin. This difference in mechanism means that prior heparin therapy does not eliminate the need for the initial higher dosing of rivaroxaban. Proper transition between these medications is crucial to maintain continuous therapeutic anticoagulation while minimizing bleeding risk, as supported by studies such as 2. Key points to consider in the management of pulmonary embolism include:
- The importance of risk stratification to guide treatment decisions
- The use of anticoagulants with rapid onset of action for initial treatment
- The consideration of direct oral anticoagulants (DOACs) for long-term treatment, as discussed in 3
- The need for individualized assessment of the risk-to-benefit ratio of anticoagulation beyond the initial 3-month treatment period, taking into account factors such as the type of index event, age, sex, D-dimer, and residual venous obstruction. Overall, the management of pulmonary embolism requires careful consideration of the patient's clinical presentation, risk factors, and treatment options to optimize outcomes and minimize complications, as highlighted in studies such as 4 and 5.