What is the recommended dose of amoxicillin (amoxicillin) for a child with otitis media (middle ear infection) weighing 12.4 kg?

Amoxicillin Dosing for Otitis Media in a 12.4 kg Child

For a 12.4 kg child with otitis media, the recommended dose of amoxicillin is 80-90 mg/kg/day divided in two doses, which equals approximately 500-550 mg twice daily. 1

Dosing Calculation and Rationale

The dosing recommendation for amoxicillin in acute otitis media (AOM) follows a high-dose strategy to overcome resistant strains of Streptococcus pneumoniae:

• Weight-based calculation: 12.4 kg × 80-90 mg/kg/day = 992-1,116 mg/day
• Divided into two doses: 496-558 mg twice daily

This high-dose regimen (80-90 mg/kg/day) is strongly recommended by multiple guidelines including:

• The American Academy of Pediatrics (AAP) 1
• The American Academy of Family Physicians (AAFP) 1
• International guidelines from the US, Japan, and South Korea 1

Treatment Algorithm

1. First-line therapy: High-dose amoxicillin (80-90 mg/kg/day divided twice daily) 1

   • Duration: 5-7 days for children ≥2 years old
   • Duration: 10 days for children <2 years old

2. When to use alternative antibiotics:

   • If the child received amoxicillin in the past 30 days
   • If the child has concurrent purulent conjunctivitis
   • If the child has a history of recurrent AOM unresponsive to amoxicillin
   • In these cases, use amoxicillin-clavulanate at the same high dose 1

3. Reassessment:

   • If symptoms worsen or fail to improve within 48-72 hours, reassess and consider changing antibiotics 1

Evidence Strength and Rationale

The recommendation for high-dose amoxicillin is based on:

1. Increasing prevalence of penicillin-resistant S. pneumoniae requiring higher concentrations to achieve bacterial eradication 2

2. Studies showing that standard-dose amoxicillin (40-45 mg/kg/day) is inadequate to eradicate resistant pneumococci, particularly during viral co-infection 3

3. Research demonstrating good bacteriologic efficacy (92% for S. pneumoniae) with high-dose amoxicillin 2

Important Clinical Considerations

• Pain management: Address pain relief regardless of antibiotic choice, especially during the first 24 hours 1

• Administration: Give amoxicillin at the start of a meal to minimize gastrointestinal intolerance 4

• Common pitfalls:

  1. Using standard-dose amoxicillin (40-45 mg/kg/day), which is insufficient for resistant strains
  2. Failing to reassess after 48-72 hours if symptoms persist
  3. Not considering alternative antibiotics when appropriate (recent amoxicillin use, concurrent conjunctivitis)

• Follow-up: Treatment should continue for a minimum of 48-72 hours beyond symptom resolution 4

The high-dose amoxicillin regimen balances efficacy against resistant pathogens with safety, cost-effectiveness, and palatability considerations, making it the optimal first-line choice for this 12.4 kg child with otitis media.