What is the appropriate amoxicillin dosage for a 17‑month‑old child weighing 10.3 kg with acute otitis media?

Amoxicillin Dosing for 17-Month-Old with Acute Otitis Media

For a 17-month-old child weighing 10.3 kg with an ear infection, give high-dose amoxicillin at 90 mg/kg/day divided into 2 doses, which equals approximately 465 mg twice daily (930 mg total daily dose) for 10 days. 1

Rationale for High-Dose Therapy

This child has multiple indications for high-dose amoxicillin therapy:

• Age under 2 years is a primary risk factor requiring high-dose therapy (90 mg/kg/day) rather than standard dosing 1
• High-dose amoxicillin (80-90 mg/kg/day) achieves middle ear fluid concentrations adequate to overcome penicillin-resistant Streptococcus pneumoniae, which is the most common bacterial pathogen in this age group 2, 1
• The American Academy of Pediatrics specifically recommends 90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate in 2 divided doses for children under 2 years with acute otitis media 1

Practical Dosing Calculation

For this 10.3 kg child:

• Total daily dose: 90 mg/kg × 10.3 kg = 927 mg/day
• Divided into 2 doses: approximately 465 mg twice daily (every 12 hours) 1
• Treatment duration: 10 days 2, 1

When to Use Amoxicillin-Clavulanate Instead

Consider switching to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day clavulanate) if: 2, 1

• The child received antibiotics within the past 30 days
• Severe illness at presentation (high fever, severe otalgia)
• Treatment failure after 48-72 hours on amoxicillin alone
• Bilateral acute otitis media in this age group
• Incomplete Haemophilus influenzae type b vaccination

Expected Clinical Response and Monitoring

• Clinical improvement should occur within 48-72 hours of starting therapy 2, 1
• Fever should decline within 48-72 hours, and irritability/fussiness should lessen 2
• If no improvement or worsening after 48-72 hours, switch to amoxicillin-clavulanate at the same high-dose regimen 2, 1

Common Pitfalls to Avoid

• Do not use standard-dose amoxicillin (40-45 mg/kg/day) in children under 2 years with acute otitis media - this leads to treatment failure with resistant organisms 1
• Verify the suspension concentration before calculating volume to avoid dosing errors 1
• The high-dose regimen has similar adverse effect rates to standard dosing, so concerns about tolerability should not prevent appropriate dosing 1, 3

Evidence Supporting High-Dose Therapy

High-dose amoxicillin (80 mg/kg/day) achieved bacteriologic eradication in 92% of S. pneumoniae isolates, including penicillin-nonsusceptible strains, in children with acute otitis media 3. The predominant pathogens causing treatment failure were beta-lactamase-producing H. influenzae (62% of failures), which would require switching to amoxicillin-clavulanate 3.