How to switch from warfarin to apixaban (direct oral anticoagulant)?

Switching from Warfarin to Apixaban

When switching from warfarin to apixaban, discontinue warfarin and start apixaban when the INR is below 2.0. 1

Protocol for Switching from Warfarin to Apixaban

Step 1: Discontinue Warfarin

• Stop warfarin therapy 1
• Monitor INR levels until they fall below 2.0 1
• Do not administer apixaban until INR is confirmed to be below 2.0 1

Step 2: Initiate Apixaban

• Start apixaban at the appropriate dose based on the indication and patient characteristics once INR is <2.0 1
• For non-valvular atrial fibrillation: standard dose is 5 mg twice daily 1
• Reduced dose of 2.5 mg twice daily for patients with at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 1

Step 3: Monitoring After Switch

• No routine coagulation monitoring is required for patients on apixaban 2
• Unlike warfarin, apixaban does not require regular INR monitoring 2
• Although apixaban can affect INR values, INR is not a reliable measure of apixaban's anticoagulant effect 3

Important Considerations

Renal Function Assessment

• Evaluate renal function before switching to apixaban 4
• Apixaban has shown a favorable safety profile across different renal function groups, including those with severe renal impairment 4, 5
• For patients with severe renal impairment, dose adjustments may be necessary 1

Contraindications and Precautions

• Do not use apixaban in patients with:
  • Active pathological bleeding 1
  • Severe hypersensitivity to apixaban 1
  • Mechanical heart valves (apixaban is less effective than warfarin for prevention of valve thrombosis) 6

Temporary Interruption for Procedures

• For elective procedures with moderate to high bleeding risk: discontinue apixaban at least 48 hours prior 1
• For procedures with low bleeding risk: discontinue apixaban at least 24 hours prior 1
• Restart apixaban as soon as adequate hemostasis has been established 1

Drug Interactions

• Assess for medications that are combined P-glycoprotein (P-gp) and strong CYP3A4 inhibitors 1
• If patient is taking such medications, reduce apixaban dose by 50% (for patients on 5 mg or 10 mg twice daily) 1
• For patients already on 2.5 mg twice daily, avoid coadministration with combined P-gp and strong CYP3A4 inhibitors 1

Common Pitfalls to Avoid

• Premature initiation of apixaban: Starting apixaban before INR is below 2.0 can increase bleeding risk 1
• Misinterpreting INR values: INR is not a reliable measure of apixaban's anticoagulant activity, despite apixaban potentially affecting INR values 3
• Failure to educate patients: Patients switching from warfarin to apixaban should be informed that they no longer need regular INR monitoring 2
• Overlooking drug interactions: Failing to adjust apixaban dose when used with strong CYP3A4 and P-gp inhibitors can lead to increased bleeding risk 1