What are the guidelines for switching from warfarin to apixaban ( Eliquis ) in patients with non-valvular atrial fibrillation?

Guidelines for Switching from Warfarin to Apixaban in Non-valvular Atrial Fibrillation

When switching from warfarin to apixaban in patients with non-valvular atrial fibrillation, discontinue warfarin and begin apixaban when the INR falls below 2.0 to ensure optimal anticoagulation coverage without excessive bleeding risk. 1

Rationale for Switching to Apixaban

• NOACs, including apixaban, are recommended over warfarin in eligible patients with non-valvular AF due to their superior safety profile and at least non-inferior efficacy for stroke prevention 1
• Apixaban has demonstrated superiority to warfarin in:
  • Reducing stroke and systemic embolism (hazard ratio 0.79; 95% CI, 0.66-0.95) 2, 3
  • Causing less major bleeding (hazard ratio 0.69; 95% CI, 0.60-0.80) 2, 3
  • Reducing all-cause mortality (hazard ratio 0.89; 95% CI, 0.80-0.99) 2, 3
• Real-world data confirms these benefits with significant risk reductions in stroke/systemic embolism (HR: 0.67) and major bleeding (HR: 0.60) compared to warfarin 4

Patient Selection for Switching

• Apixaban is appropriate for patients with non-valvular AF, defined as AF without moderate-to-severe mitral stenosis or mechanical heart valve 1
• Apixaban can be used in patients with other valvular heart disease including:
  • Mild mitral stenosis
  • Mitral regurgitation
  • Aortic stenosis or regurgitation
  • Tricuspid regurgitation
  • Bioprosthetic valves
  • Previous valve repair or valvuloplasty 1, 5
• Contraindications to apixaban:
  • Mechanical heart valves 1
  • Moderate-to-severe mitral stenosis 1
  • End-stage CKD (CrCl <15 mL/min) or patients on dialysis (use reduced doses with caution in moderate-to-severe CKD) 1

Switching Protocol

1. Assess patient's current INR level 1
2. Discontinue warfarin and monitor INR decline 1
3. Start apixaban when INR falls below 2.0 1
   • Standard dose: 5 mg twice daily 2
   • Reduced dose (2.5 mg twice daily) if patient has at least 2 of the following:
     • Age ≥80 years
     • Body weight ≤60 kg
     • Serum creatinine ≥1.5 mg/dL 2

Pre-Switching Evaluation

• Evaluate renal function before initiating apixaban 1
• Assess hepatic function before starting apixaban 1
• Review potential drug interactions 1
• Ensure patient understands the importance of strict adherence to twice-daily dosing 1

Post-Switching Monitoring

• Reevaluate renal and hepatic function at least annually 1
• Monitor for signs of bleeding or thromboembolism 1
• Assess medication adherence at follow-up visits 1
• No routine coagulation monitoring is required for apixaban (unlike warfarin) 1

Special Considerations

• Elderly patients: Apixaban has shown favorable outcomes in elderly populations, but use reduced dose criteria when applicable 4, 6
• Renal impairment: Dose adjustment may be needed; apixaban has lower renal clearance (25%) compared to dabigatran (80%) 1
• Patients switching from warfarin to apixaban: Medicare data shows improved outcomes with significantly lower rates of stroke/systemic embolism and major bleeding compared to switching to other DOACs 6
• Perioperative management: Unlike warfarin, bridging therapy with heparin is generally not required when temporarily discontinuing apixaban for procedures 1

Common Pitfalls to Avoid

• Overlapping warfarin and apixaban: This can increase bleeding risk; start apixaban only after INR is below 2.0 1
• Inadequate patient education: Patients must understand the importance of twice-daily dosing and that missing doses can lead to loss of anticoagulation protection 1
• Failure to reassess renal/hepatic function: Regular monitoring is essential as changes may require dose adjustment 1
• Inappropriate dosing: Using reduced dose without meeting criteria or standard dose when reduction is indicated 2