Is switching a patient from apixaban 2.5 mg twice daily to rivaroxaban (Xarelto) 15 mg once daily for a 90‑day supply an equivalent dose exchange?

No, this is NOT an equivalent exchange

Switching from apixaban 2.5 mg twice daily to rivaroxaban 15 mg once daily is not an appropriate dose conversion and should not be done without careful clinical evaluation. These are fundamentally different anticoagulation regimens with distinct dosing rationales, and the proposed switch may expose the patient to either inadequate anticoagulation or increased bleeding risk depending on their clinical context.

Key Issues with This Proposed Switch

Different Dose Contexts

Apixaban 2.5 mg twice daily is a reduced dose used in specific clinical scenarios 1, 2, 3:

• Patients with atrial fibrillation who meet at least 2 of 3 criteria: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL
• For extended secondary prevention after completing 6 months of treatment for DVT/PE
• Post-left atrial appendage closure in select patients

Rivaroxaban 15 mg once daily is also a reduced dose but used for different indications 1, 2:

• Patients with atrial fibrillation and creatinine clearance 15-50 mL/min
• This is NOT the standard dose for most AF patients (which is 20 mg daily)

The Critical Problem

The proposed switch lacks clinical context. Without knowing:

• Why the patient is on apixaban 2.5 mg (dose reduction criteria vs. extended VTE prophylaxis)
• The patient's renal function (rivaroxaban 15 mg is specifically for CrCl 15-50 mL/min)
• The indication for anticoagulation (AF vs. VTE)

This switch could be inappropriate. For example:

• If the patient is on apixaban 2.5 mg for AF based on age/weight/creatinine criteria but has normal renal function, switching to rivaroxaban 15 mg would be underdosing (should be 20 mg)
• If the patient is on apixaban 2.5 mg for extended VTE prophylaxis, rivaroxaban 15 mg is not the equivalent dose (should be 20 mg for VTE treatment in patients with normal renal function)

Proper Approach to DOAC Switching

When switching between DOACs, discontinue the first agent and begin the new agent at the time of the next scheduled dose 3. However, the dose of the new agent must be appropriate for the patient's:

1. Indication (AF vs. VTE)
2. Renal function (calculate creatinine clearance)
3. Other dose-reduction criteria (age, weight, serum creatinine for apixaban; renal function for rivaroxaban)

For Atrial Fibrillation Patients

If switching from apixaban to rivaroxaban in AF 1, 2:

• CrCl >50 mL/min: Use rivaroxaban 20 mg once daily (not 15 mg)
• CrCl 15-50 mL/min: Use rivaroxaban 15 mg once daily

For VTE Treatment

If switching from apixaban to rivaroxaban for VTE:

• Standard dose is rivaroxaban 15 mg twice daily for 21 days, then 20 mg once daily
• For extended prophylaxis after initial treatment, rivaroxaban 20 mg once daily (or 15 mg if CrCl 15-50 mL/min)

Safety Considerations

Real-world evidence suggests switching between apixaban and rivaroxaban carries risks 4, 5:

• Switching from apixaban to rivaroxaban was associated with higher stroke/systemic embolism risk (HR 1.99) and higher major bleeding risk (HR 1.80) compared to continuing apixaban 4
• Apixaban has consistently shown lower major bleeding rates compared to rivaroxaban in head-to-head observational studies 5, 6

Recommendation

Do not proceed with this switch as written. Instead:

1. Clarify the indication: Why is the patient on anticoagulation? (AF, VTE, other)
2. Assess renal function: Calculate creatinine clearance
3. Review dose-reduction criteria: Does the patient meet criteria for reduced dosing?
4. Determine appropriate rivaroxaban dose:
   • For AF with CrCl >50 mL/min: 20 mg daily
   • For AF with CrCl 15-50 mL/min: 15 mg daily
   • For VTE: Follow standard VTE dosing protocol
5. Consider whether switching is necessary: Given the increased risks associated with switching from apixaban to rivaroxaban, continuation of apixaban may be preferable unless there is a compelling clinical reason to switch

If there is a specific reason necessitating the switch to rivaroxaban (e.g., cost, formulary restrictions), ensure the dose is appropriate for the patient's clinical context—this likely means 20 mg daily for most AF patients with normal renal function, not 15 mg.