What is the appropriate amoxicillin dosing for a healthy 5-year-old child weighing 16.8 kg with acute otitis media?

Amoxicillin Dosing for Acute Otitis Media in a 5-Year-Old

For this 5-year-old child weighing 16.8 kg with acute otitis media, prescribe high-dose amoxicillin at 80–90 mg/kg/day divided into two doses for 10 days, which equals 1,344–1,512 mg total daily (672–756 mg per dose given every 12 hours). 1

Dosing Calculation and Administration

• Calculate the total daily dose by multiplying 16.8 kg × 80–90 mg/kg = 1,344–1,512 mg/day, then divide into two equal doses given 12 hours apart. 1
• The American Academy of Pediatrics recommends this high-dose regimen (80–90 mg/kg/day in 2 divided doses) as first-line therapy for children younger than 6 years with acute otitis media. 1, 2
• Treatment duration should be 10 days for children under 6 years of age. 1, 3

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 regimen provides adequate coverage against the three principal bacterial pathogens: S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. 1, 2
• Research demonstrates that standard-dose amoxicillin (40 mg/kg/day) is inadequate to effectively eradicate resistant S. pneumoniae, particularly during viral coinfection. 4

When to Switch to Amoxicillin-Clavulanate

Consider switching to high-dose amoxicillin-clavulanate (90 mg/kg/day amoxicillin + 6.4 mg/kg/day clavulanate in 14:1 ratio, divided BID) if: 1, 3, 2

• 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)
• No clinical improvement occurs within 48–72 hours on amoxicillin alone

Monitoring and Treatment Failure

• Clinical improvement should be evident within 48–72 hours; if no improvement occurs, first reassess the diagnosis of acute otitis media. 1, 3
• If the diagnosis is confirmed and the child fails to improve on amoxicillin alone, switch to high-dose amoxicillin-clavulanate. 1, 2
• If the child fails amoxicillin-clavulanate, consider ceftriaxone 50 mg/kg administered intramuscularly or intravenously for three days. 1, 3

Important Clinical Caveats

• The 14:1 ratio formulation of amoxicillin-clavulanate causes significantly less diarrhea than older 7:1 formulations and should be used when combination therapy is needed. 1, 3
• Twice-daily dosing offers similar efficacy to three-times-daily regimens and improves adherence by reducing scheduling difficulties for caregivers. 5
• High-dose amoxicillin-clavulanate achieves 96% eradication of S. pneumoniae from middle ear fluid by days 4–6, significantly superior to azithromycin. 1, 3