Apixaban Dosing for Atrial Fibrillation
The standard dose of apixaban for nonvalvular atrial fibrillation is 5 mg orally twice daily, with dose reduction to 2.5 mg twice daily ONLY if the patient meets at least TWO of the following criteria: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL. 1
Standard Dosing Algorithm
Most patients should receive 5 mg twice daily as this was the dose proven effective in the ARISTOTLE trial, which demonstrated a 21% reduction in stroke or systemic embolism compared to warfarin (HR 0.79,95% CI 0.66-0.95) and a 31% reduction in major bleeding 2, 3. The twice-daily dosing is necessary due to apixaban's 9-14 hour half-life 3.
Dose Reduction Criteria (Must Meet ≥2 Criteria)
Reduce to 2.5 mg twice daily only when the patient has at least TWO of these characteristics 1, 4:
- Age ≥80 years
- Body weight ≤60 kg
- Serum creatinine ≥1.5 mg/dL (approximately 133 μmol/L)
Critical point: Patients with only ONE dose-reduction criterion should receive the standard 5 mg twice daily dose. This is supported by post-hoc analysis of ARISTOTLE showing that patients with a single criterion had similar efficacy (HR 0.94,95% CI 0.66-1.32 for stroke) and safety (HR 0.68,95% CI 0.53-0.87 for major bleeding) with 5 mg twice daily compared to warfarin 5.
Renal Function Considerations
- CrCl >30 mL/min: Apply standard dosing algorithm above 4
- CrCl 15-30 mL/min (severe impairment): Use 5 mg twice daily unless ≥2 dose-reduction criteria are met 4, 3
- End-stage renal disease on hemodialysis: Start with 5 mg twice daily, reduce to 2.5 mg twice daily only if age ≥80 years OR body weight ≤60 kg (note: only need ONE criterion in dialysis patients) 4
- CrCl <15 mL/min NOT on dialysis: Apixaban is contraindicated 4, 1
Common Prescribing Errors to Avoid
Underdosing is a significant problem in clinical practice. Studies show that 60.8% of patients receiving reduced-dose apixaban did not meet labeling criteria for dose reduction 6. The most common error is reducing the dose based on a single criterion—particularly age ≥80 years alone (56% of inappropriate reductions) 7, 6.
Do not reduce the dose based on:
- Perceived bleeding risk alone 7
- Age ≥80 years as the only criterion 5
- Body weight ≤60 kg as the only criterion 5
- Serum creatinine ≥1.5 mg/dL as the only criterion 5
Administration Details
- No loading dose required 4
- No bridging anticoagulation needed when initiating 4
- No routine coagulation monitoring required 4, 3
- Timing: Can be taken with or without food 1
- Missed dose: Take as soon as remembered on the same day; do not double the next dose 1
Switching Between Anticoagulants
From warfarin to apixaban: Discontinue warfarin and start apixaban when INR falls below 2.0 1, 4
From apixaban to warfarin: Discontinue apixaban and begin both parenteral anticoagulant AND warfarin at the time of the next scheduled apixaban dose; continue parenteral anticoagulant until INR reaches therapeutic range 1, 4
From other DOACs to apixaban: Simply start apixaban at the time the next dose of the previous DOAC would have been due 4
Special Populations
Prior stroke or TIA: Use the same dosing algorithm; apixaban benefit is independent of prior stroke history 4, 2
Concurrent antiplatelet therapy: If needed after coronary intervention, use clopidogrel (not aspirin) with apixaban after a brief periprocedural period to reduce bleeding risk 4
Stable coronary disease without recent PCI: Apixaban monotherapy is appropriate; adding antiplatelet therapy increases bleeding without clear benefit 4