What is the equivalent dosage of Xarelto (rivaroxaban) for a patient on Pradaxa (dabigatran) 150 mg twice daily (bid) for stroke prevention in atrial fibrillation?

Equivalent Dosage of Xarelto for a Patient on Pradaxa 150 mg BID

For a 65-year-old female transitioning from Pradaxa (dabigatran) 150 mg twice daily to Xarelto (rivaroxaban), the equivalent dosage is 20 mg once daily with the evening meal, assuming normal renal function.

Dosing Rationale

The conversion from dabigatran to rivaroxaban should be based on FDA-approved dosing for atrial fibrillation:

• Dabigatran 150 mg twice daily is the standard dose for stroke prevention in atrial fibrillation for patients with CrCl >30 mL/min 1
• The equivalent standard dose of rivaroxaban is 20 mg once daily taken with the evening meal 1

Dosing Algorithm Based on Renal Function

Renal function assessment is critical before converting between DOACs:

1. Normal to mildly impaired renal function (CrCl ≥50 mL/min):

   • Rivaroxaban 20 mg once daily with the evening meal

2. Moderate renal impairment (CrCl 30-49 mL/min):

   • Rivaroxaban 15 mg once daily with the evening meal 1

3. Severe renal impairment (CrCl 15-29 mL/min):

   • Rivaroxaban 15 mg once daily with the evening meal 2
   • Some evidence suggests 10 mg once daily may be appropriate 3

Transition Process

When switching from dabigatran to rivaroxaban:

1. Discontinue dabigatran
2. Start rivaroxaban at the time the next dose of dabigatran would have been due
3. No overlap period is needed between the medications

Important Clinical Considerations

• Administration timing: Unlike dabigatran (taken twice daily), rivaroxaban must be taken once daily with the evening meal to ensure adequate absorption 1

• Monitoring: No routine coagulation monitoring is required for either medication 2

• Efficacy comparison: Both medications are effective for stroke prevention in atrial fibrillation, with rivaroxaban showing noninferiority to warfarin in the ROCKET-AF trial 1, 4

• Bleeding risk: The incidence of major or clinically relevant non-major bleeding with rivaroxaban was reported as 8.4 events per 100 person-years in recent studies 5

Potential Pitfalls and Caveats

• Renal function: Always assess renal function before conversion, as both medications require dose adjustments based on creatinine clearance 1

• Drug interactions: Rivaroxaban is contraindicated with combined P-glycoprotein and strong CYP3A4 inducers 1

• Compliance considerations: Transitioning from a twice-daily medication (dabigatran) to a once-daily medication (rivaroxaban) may improve adherence, but missing a dose of rivaroxaban has potentially greater impact due to its once-daily dosing

• Meal requirement: Unlike dabigatran, rivaroxaban absorption is significantly affected by food intake and must be taken with the evening meal 1

• Dyspepsia: If the patient was switched from dabigatran due to dyspepsia (a common side effect), rivaroxaban may be better tolerated 1

By following these guidelines, the transition from Pradaxa 150 mg twice daily to Xarelto can be accomplished safely and effectively while maintaining appropriate anticoagulation for stroke prevention.