Apixaban Dosing for Atrial Fibrillation
The standard dose of apixaban for atrial fibrillation is 5 mg orally twice daily, with dose reduction to 2.5 mg twice daily ONLY when patients meet at least TWO of the following criteria: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL. 1, 2, 3
Standard Dosing Algorithm
Start with 5 mg twice daily for the vast majority of patients with nonvalvular atrial fibrillation, as this regimen demonstrated a 21% reduction in stroke or systemic embolism (HR 0.79,95% CI 0.66-0.95) and a 31% reduction in major bleeding compared to warfarin in the ARISTOTLE trial 4, 2
No loading dose or bridging anticoagulation is required when initiating apixaban 4
Dose Reduction Criteria: The "Two Out of Three" Rule
Reduce to 2.5 mg twice daily ONLY when ≥2 of these are present: 1, 2, 3
- Age ≥80 years
- Body weight ≤60 kg
- Serum creatinine ≥1.5 mg/dL
Critical pitfall: In real-world practice, approximately 60% of patients receiving reduced-dose apixaban do not actually meet the criteria for dose reduction 5. Clinicians frequently underdose based on a single criterion (particularly age alone), which is incorrect and may expose patients to inadequate stroke protection 5. You must have TWO criteria present, not just one.
Renal Function Considerations
CrCl >30 mL/min: Apply the standard dosing algorithm above (5 mg twice daily unless ≥2 dose-reduction criteria met) 1, 2
CrCl 15-30 mL/min: Use 5 mg twice daily unless ≥2 dose-reduction criteria are met, then use 2.5 mg twice daily 1, 2
End-stage renal disease on hemodialysis: Start with 5 mg twice daily, reducing to 2.5 mg twice daily ONLY if age ≥80 years OR body weight ≤60 kg (note: only ONE criterion needed in dialysis patients, not two) 4, 2
CrCl <15 mL/min NOT on dialysis: Apixaban is contraindicated 4, 3
CrCl >95 mL/min: Edoxaban is contraindicated in this range, but apixaban 5 mg twice daily remains appropriate 1
Special Clinical Scenarios
Prior Stroke or TIA
- Use the same dosing algorithm as for patients without prior stroke—the benefit of apixaban is independent of stroke history 4, 2
- Recent data suggest patients with subclinical atrial fibrillation and prior stroke/TIA derive greater absolute benefit from apixaban (7% absolute risk reduction over 3.5 years) compared to those without prior stroke (1% absolute risk reduction) 6
Concurrent Antiplatelet Therapy
- After coronary intervention, use apixaban with clopidogrel (NOT aspirin) after a brief periprocedural period to reduce bleeding risk while maintaining efficacy 4, 2
- The AUGUSTUS trial demonstrated that appropriately reduced-dose apixaban (when dose-reduction criteria met) had similar safety and efficacy to standard-dose apixaban in patients with recent ACS or PCI 7
Monitoring Requirements
Assess renal function before starting and at least annually thereafter, with more frequent monitoring (every 3-6 months) if CrCl 30-50 mL/min or other risk factors for deterioration present 4, 2
No routine coagulation monitoring (INR, aPTT) is required 1, 4
Evaluate body weight periodically, particularly in patients near the 60 kg threshold, as weight changes may affect dose-reduction criteria 2
Assess clinically for signs of bleeding or thromboembolism at follow-up visits 1, 2
Switching Between Anticoagulants
From Warfarin to Apixaban
From Apixaban to Warfarin
- Discontinue apixaban and begin BOTH parenteral anticoagulant AND warfarin at the time of the next scheduled apixaban dose, continuing parenteral anticoagulant until INR reaches therapeutic range 4, 3
From Other DOACs to Apixaban
- Simply discontinue the other DOAC and start apixaban at the time the next dose of the previous DOAC would have been due 4