What is the appropriate amoxicillin dose for acute otitis media in a child weighing 22.23 kg?

Amoxicillin Dose Calculation for AOM in a 22.23 kg Child

For this 22.23 kg child with acute otitis media, prescribe high-dose amoxicillin at 1,780–2,000 mg total daily dose, divided into two doses of 890–1,000 mg given every 12 hours for 10 days. 1, 2, 3

Dosing Calculation

• Multiply the child's weight (22.23 kg) by 80–90 mg/kg/day to determine the total daily dose: 2

  • Lower end: 22.23 kg × 80 mg/kg = 1,778 mg/day (round to 1,780 mg)
  • Upper end: 22.23 kg × 90 mg/kg = 2,001 mg/day (round to 2,000 mg)

• Divide the total daily dose into two equal doses given 12 hours apart: 2

  • 890 mg twice daily (if using 80 mg/kg/day)
  • 1,000 mg twice daily (if using 90 mg/kg/day)

• The maximum single dose of amoxicillin is 2,000 mg, which this child does not exceed. 1

Rationale for High-Dose Therapy

• High-dose amoxicillin (80–90 mg/kg/day) 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, 2

• This regimen provides adequate coverage against the three principal AOM pathogens: S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 2, 3

• The American Academy of Pediatrics recommends high-dose amoxicillin as first-line therapy for most uncomplicated AOM cases due to its effectiveness, safety profile, low cost, and narrow antimicrobial spectrum. 1, 3

Treatment Duration and Monitoring

• Treat for 10 days. 1, 2

• Clinical improvement should be evident within 48–72 hours; if no improvement occurs, reassess the diagnosis and consider treatment failure. 1, 2

• If treatment fails after 48–72 hours on amoxicillin alone, switch to high-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate in a 14:1 ratio, divided twice daily). 1, 2, 3

When to Use Amoxicillin-Clavulanate Instead

Consider starting with high-dose amoxicillin-clavulanate rather than amoxicillin alone if any of the following apply: 1, 2, 3

• The child received amoxicillin within the previous 30 days
• Concurrent purulent conjunctivitis is present
• The child attends daycare (increased risk of β-lactamase-producing organisms)
• The child is younger than 2 years with high-risk features

Important Clinical Caveats

• Twice-daily dosing is as effective as three-times-daily dosing and improves adherence by reducing scheduling difficulties for caregivers. 4

• If amoxicillin-clavulanate is needed, use only the 14:1 ratio formulation (90 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate), as it causes significantly less diarrhea than older 7:1 formulations while maintaining efficacy. 1, 2

• For penicillin-allergic children, alternative options include cefdinir (14 mg/kg/day), cefuroxime (30 mg/kg/day in 2 divided doses), or cefpodoxime (10 mg/kg/day in 2 divided doses). 1, 3