How to switch from warfarin to Eliquis (apixaban)?

How to Switch from Warfarin to Eliquis (Apixaban)

Discontinue warfarin and start apixaban when the INR falls below 2.0. 1, 2, 3

Pre-Switch Verification

Before initiating the switch, confirm the following:

• Verify the indication for anticoagulation - Patients with mechanical heart valves or moderate-to-severe mitral stenosis are absolute contraindications and must remain on warfarin. 1, 2, 3
• Assess renal function - While apixaban can be used in advanced chronic kidney disease (CrCl 25-30 mL/min), exercise caution in end-stage renal disease or hemodialysis patients where warfarin may be preferred. 2, 4
• Confirm the target INR range - Most patients with atrial fibrillation or venous thromboembolism have a target INR of 2.0-3.0. 5

Switching Protocol

The FDA-approved method for transitioning from warfarin to apixaban follows a straightforward approach:

• Stop warfarin immediately and monitor the INR. 3
• Wait for INR to fall below 2.0 before initiating apixaban - This typically takes 3-5 days depending on the patient's warfarin dose and individual metabolism. 1, 2, 3
• Start apixaban at the appropriate dose once INR is below 2.0:
  • Standard dose: 5 mg twice daily 3
  • Reduced dose: 2.5 mg twice daily if the patient has at least 2 of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 3

Bridging Considerations

Bridging anticoagulation is NOT recommended during the transition from warfarin to apixaban in most patients. 1, 3 The European Society of Cardiology guidelines specifically state that bridging is not necessary when switching from warfarin to direct oral anticoagulants. 1

However, in very high-risk patients (mechanical mitral valve, recent thromboembolism within 3 months, or history of thromboembolism while anticoagulated), consider bridging with low molecular weight heparin during the transition period. 5

Post-Switch Management

After successfully transitioning to apixaban:

• No routine INR monitoring is required - This is a key advantage of apixaban over warfarin. 2
• Assess renal function periodically, especially in elderly patients, as apixaban dosing may need adjustment. 2, 3
• Evaluate bleeding risk factors at regular intervals including age, history of gastrointestinal bleeding, concurrent antiplatelet use, and fall risk. 2
• Counsel patients on bleeding signs to report immediately: unusual bruising, blood in urine or stool, prolonged bleeding from cuts, severe headache, dizziness, or weakness. 6

Common Pitfalls to Avoid

• Do not start apixaban while INR is still ≥2.0 - This creates overlapping anticoagulation and increases bleeding risk. 3
• Do not use bridging anticoagulation routinely - The 24-48 hour period after stopping warfarin does not generally require bridging. 3
• Do not switch patients with mechanical valves - These patients were excluded from apixaban trials and must remain on warfarin. 1, 2
• Do not forget to verify drug interactions - Reduce apixaban dose by 50% if the patient is taking combined P-gp and strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir). 3

Evidence Supporting the Switch

Recent comparative effectiveness data demonstrate that apixaban has a superior safety profile compared to warfarin in patients with atrial fibrillation and advanced chronic kidney disease, with significantly lower rates of major bleeding (HR 0.34), major or clinically relevant non-major bleeding (HR 0.35), and intracranial hemorrhage. 4, 7 The ARISTOTLE trial data support conventional dosing even in patients with CrCl 25-30 mL/min. 4