What is the recommended dose of Apixaban (apixaban) for patients weighing less than 60kg?

Apixaban Dosing for Patients Weighing Less Than 60 kg

For patients weighing less than 60 kg, the recommended dose of apixaban should be reduced to 2.5 mg twice daily if they also have at least one additional dose-reduction criterion (age ≥80 years or serum creatinine ≥1.5 mg/dL); otherwise, the standard dose of 5 mg twice daily should be maintained. 1, 2

Dose Reduction Criteria for Apixaban

Apixaban dosing is determined by specific patient characteristics, particularly in the context of nonvalvular atrial fibrillation:

• Standard dose: 5 mg twice daily
• Reduced dose: 2.5 mg twice daily when at least two of the following criteria are present:
  • Age ≥80 years
  • Body weight ≤60 kg
  • Serum creatinine ≥1.5 mg/dL (133 μmol/L)

Important considerations:

• Low body weight (≤60 kg) alone is not sufficient to warrant dose reduction 1, 2
• Reduced dose is also recommended for patients with severe renal impairment (CrCl 15-29 mL/min) regardless of other factors 1
• Apixaban is not recommended for patients with CrCl <15 mL/min or those on dialysis 2

Clinical Evidence Supporting This Approach

The ARISTOTLE trial demonstrated that patients with only one dose-reduction criterion (including weight ≤60 kg alone) who received the standard 5 mg twice daily dose showed consistent benefits compared to warfarin, with similar safety profiles to those without any dose-reduction criteria 3.

• Patients with only one dose-reduction criterion had higher baseline risk of stroke/systemic embolism (HR 1.47) and major bleeding (HR 1.89) compared to those with no criteria
• However, the relative benefit of apixaban 5 mg twice daily vs. warfarin remained consistent regardless of whether patients had one or no dose-reduction criteria 3

Algorithm for Apixaban Dosing in Patients <60 kg

1. Assess all three dose-reduction criteria:

   • Weight ≤60 kg
   • Age ≥80 years
   • Serum creatinine ≥1.5 mg/dL

2. Determine appropriate dose:

   • If ≥2 criteria present: Use 2.5 mg twice daily
   • If only weight ≤60 kg (or only one criterion): Use 5 mg twice daily
   • If severe renal impairment (CrCl 15-29 mL/min): Use 2.5 mg twice daily

3. Special clinical scenarios:

   • For VTE treatment: Start with 10 mg twice daily for 7 days, then 5 mg twice daily (no dose reduction for weight alone) 2
   • For VTE prophylaxis after orthopedic surgery: Use 2.5 mg twice daily regardless of weight 1, 2

Clinical Pitfalls to Avoid

• Inappropriate dose reduction: Reducing dose based on weight alone may lead to suboptimal anticoagulation and increased thrombotic risk 4
• Failure to reduce dose when indicated: Not reducing dose when multiple criteria are present increases bleeding risk 5
• Overlooking renal function: Creatinine clearance should be calculated using the Cockcroft-Gault formula, not estimated GFR 1, 2
• Medication interactions: P-glycoprotein and CYP3A4 inhibitors may increase apixaban levels and bleeding risk, requiring dose adjustment in some cases 1, 5

By following these evidence-based dosing recommendations, clinicians can optimize the balance between preventing thromboembolic events and minimizing bleeding risk in patients weighing less than 60 kg who require apixaban therapy.