Amoxicillin Dosing for Otitis Media in a 58.8-Pound Child
For a child weighing 58.8 pounds (26.7 kg) with acute otitis media, prescribe amoxicillin 80-90 mg/kg/day divided into 2 doses, which equals approximately 1,070-1,200 mg twice daily (practical dosing: 1,000-1,200 mg twice daily). 1
Dose Calculation
- The child weighs 58.8 pounds, which converts to 26.7 kg 1
- Using the recommended high-dose amoxicillin regimen of 80-90 mg/kg/day: 2, 1
- 80 mg/kg/day × 26.7 kg = 2,136 mg/day (1,068 mg twice daily)
- 90 mg/kg/day × 26.7 kg = 2,403 mg/day (1,201 mg twice daily)
- Practical prescribing: 1,000 mg twice daily (approximately 75 mg/kg/day) or 1,200 mg twice daily (approximately 90 mg/kg/day) 1
Rationale for High-Dose Therapy
- High-dose amoxicillin (80-90 mg/kg/day) is the first-line treatment for acute otitis media because it provides effective coverage against drug-resistant Streptococcus pneumoniae while maintaining safety, low cost, acceptable taste, and narrow microbiologic spectrum 2, 1
- This dosing achieves middle ear fluid concentrations adequate to overcome penicillin-resistant S. pneumoniae (MIC ≤2 mg/L) 2, 3
- Standard-dose amoxicillin (40-45 mg/kg/day) is inadequate for eradicating resistant S. pneumoniae, particularly during viral coinfection 4
Treatment Duration
- The recommended duration is 5-10 days depending on age and severity 2, 1
- For children over 2 years with uncomplicated acute otitis media, 5 days is sufficient 1
- For children under 2 years or those with severe symptoms, 10 days is recommended 2, 5
When to Use Amoxicillin-Clavulanate Instead
- Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate) if: 2, 1
- The child received antibiotics in the previous 30 days
- Concurrent purulent conjunctivitis is present
- The child is younger than 2 years
- The child attends daycare
- Coverage for beta-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis is needed
- Beta-lactamase-producing H. influenzae is the predominant pathogen in amoxicillin treatment failures 6
Reassessment and Treatment Failure
- Reassess at 48-72 hours if symptoms fail to improve 1
- Treatment failure is defined as worsening condition, persistence of symptoms beyond 48 hours, or recurrence within 4 days of completing therapy 1
- If no improvement by 48-72 hours, switch to amoxicillin-clavulanate (90/6.4 mg/kg/day) or ceftriaxone (50 mg/kg IM/IV daily) 2, 1
Important Clinical Considerations
- Pain management should be addressed concurrently during the first 24 hours 1
- The every 12-hour dosing regimen is associated with significantly less diarrhea compared to every 8-hour dosing (14% vs 34%) 5
- For this 26.7 kg child who weighs less than 40 kg, use pediatric formulations; do not use adult 500 mg/125 mg tablets 5