Bridging from Warfarin (Coumadin) to Apixaban (Eliquis)
No bridging with heparin or LMWH is required when switching from warfarin to apixaban. Simply discontinue warfarin and start apixaban when the INR falls below 2.0 1.
Step-by-Step Protocol
- Stop warfarin (Coumadin)
- Check INR daily or every other day until it falls below 2.0
- Start apixaban (Eliquis) at the appropriate dose when INR is below 2.0
- No bridging anticoagulation with heparin or low molecular weight heparin is necessary during this transition period
Dosing Considerations for Apixaban
The appropriate dose of apixaban depends on the indication:
- Atrial fibrillation: 5 mg twice daily (standard dose) or 2.5 mg twice daily if patient has at least two of the following: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL 1
- DVT/PE treatment: 10 mg twice daily for the first 7 days, then 5 mg twice daily 1
- DVT/PE prevention after orthopedic surgery: 2.5 mg twice daily 1
- Reduction in risk of recurrent DVT/PE: 2.5 mg twice daily (after at least 6 months of treatment) 1
Important Considerations
Renal Function
- Apixaban dosing should be adjusted based on renal function
- For patients with severe renal impairment (CrCl 15-29 mL/min), dose adjustment may be necessary 2, 3
- Patients with end-stage renal disease on dialysis require special consideration 4
Drug Interactions
- Reduce apixaban dose by 50% when coadministered with drugs that are combined P-glycoprotein (P-gp) and strong CYP3A4 inhibitors 1
- If patient is already on 2.5 mg twice daily, avoid coadministration with these inhibitors 1
Special Patient Populations
Antiphospholipid Syndrome
- Caution is advised when switching patients with antiphospholipid syndrome from warfarin to apixaban, as there may be an increased risk of thrombotic events, particularly stroke 5
Mechanical Heart Valves
- Apixaban is not indicated for patients with mechanical heart valves, who should remain on warfarin 6
Avoiding Common Pitfalls
Do not start apixaban while INR is still ≥2.0 - This could increase bleeding risk due to overlapping anticoagulant effects
Do not use bridging therapy - Unlike when interrupting anticoagulation for procedures, bridging with heparin or LMWH is unnecessary and potentially harmful when transitioning from warfarin to apixaban 1, 7
Do not double-dose - If a dose of apixaban is missed, take it as soon as possible on the same day and resume twice-daily dosing. Do not double the dose to make up for a missed dose 1
Avoid inappropriate dose reduction - Using lower than recommended doses of apixaban without appropriate indications may compromise efficacy without improving safety 4
By following this protocol, patients can safely transition from warfarin to apixaban without the need for bridging therapy, minimizing both bleeding risk and the risk of thromboembolic events.