What is the recommended amoxicillin dosing and treatment duration for a 10‑kg child with acute otitis media?

Amoxicillin Dosing for Acute Otitis Media in a 10-kg Child

For a 10-kg child with acute otitis media, prescribe high-dose amoxicillin at 80–90 mg/kg/day divided into two doses (400–450 mg twice daily) for 10 days. 1

Exact Dosing Calculation

• Total daily dose: Multiply 10 kg × 80–90 mg/kg = 800–900 mg per day 1
• Individual dose: Divide the total by 2 = 400–450 mg given every 12 hours 1
• Treatment duration: 10 days for children under 2 years of age 1

Rationale for High-Dose Therapy

High-dose amoxicillin achieves middle ear fluid concentrations that exceed the minimum inhibitory concentration for approximately 87% of Streptococcus pneumoniae isolates, including intermediately resistant strains, compared to only 83% coverage with standard dosing. 1 This superior pharmacodynamic profile makes high-dose amoxicillin the first-line choice, as it provides adequate coverage against the three principal pathogens: S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1

The American Academy of Pediatrics and American Academy of Family Physicians recommend amoxicillin as first-line therapy because it is generally effective when used in sufficient doses, safe, inexpensive, has an acceptable taste, and maintains a narrow microbiologic spectrum. 2

When to Switch to Amoxicillin-Clavulanate

Use high-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate in a 14:1 ratio, divided twice daily) instead of amoxicillin alone if: 1

• The child received amoxicillin within the previous 30 days 1
• Concurrent purulent conjunctivitis is present 1
• The child attends daycare (increased risk of β-lactamase-producing organisms) 3

The 14:1 ratio formulation causes significantly less diarrhea than older 7:1 formulations while preserving efficacy against β-lactamase-producing bacteria. 1

Management of Treatment Failure

If no clinical improvement occurs within 48–72 hours: 1

1. First, reassess the diagnosis to confirm acute otitis media 1
2. If initially on amoxicillin alone, switch to high-dose amoxicillin-clavulanate 1
3. If already on amoxicillin-clavulanate, consider ceftriaxone 50 mg/kg intramuscularly or intravenously for three days 1

Pain Management

Address pain during the first 24 hours regardless of antibiotic choice, as many cases of acute otitis media are associated with significant discomfort. 2 Pain management should be a primary concern and not treated as peripheral to antibiotic therapy. 2

Common Pitfalls to Avoid

• Underdosing: Using standard-dose amoxicillin (40–45 mg/kg/day) instead of high-dose (80–90 mg/kg/day) will provide inadequate coverage for resistant organisms 2, 1
• Wrong formulation: If switching to amoxicillin-clavulanate, ensure the 14:1 ratio formulation is prescribed to minimize gastrointestinal side effects 1
• Premature discontinuation: Complete the full 10-day course in children under 2 years, even if symptoms improve earlier 1