Recommended Amoxicillin Dose for Acute Otitis Media in a 39-Pound Child
For a child weighing 39 pounds (17.7 kg) with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into two doses, which equals approximately 710-800 mg twice daily for a total daily dose of 1420-1600 mg. 1, 2
First-Line Treatment Rationale
High-dose amoxicillin (80-90 mg/kg/day) is the first-line therapy for uncomplicated acute otitis media in children, providing effective coverage against drug-resistant Streptococcus pneumoniae while maintaining safety, low cost, acceptable taste, and narrow microbiologic spectrum. 3, 1, 2
The American Academy of Pediatrics specifically recommends this high-dose regimen for children under 2 years, but it applies to all pediatric patients with AOM when amoxicillin is chosen as first-line therapy. 2
Dosing Calculation and Administration
For a 17.7 kg (39 lb) child:
The medication should be divided into two doses given every 12 hours, as this regimen is associated with significantly less diarrhea compared to three-times-daily dosing. 3, 4
Duration of Treatment
Treat for 10 days in children younger than 2 years or those with severe symptoms. 3, 2
Children 2-5 years with mild-to-moderate symptoms may receive a 7-day course, though 10 days remains standard. 3
When to Use Amoxicillin-Clavulanate Instead
Switch to amoxicillin-clavulanate (high-dose formulation with 14:1 ratio at 90 mg/kg/day of the amoxicillin component) if: 3, 1, 2
- The child received amoxicillin in the previous 30 days
- Concurrent purulent conjunctivitis is present
- The child has recurrent AOM unresponsive to amoxicillin
- No clinical improvement occurs within 48-72 hours of starting amoxicillin
Critical Monitoring Points
Reassess the patient at 48-72 hours if symptoms fail to improve or worsen, as this indicates treatment failure requiring a change to amoxicillin-clavulanate or ceftriaxone. 3, 1, 2
Address pain management concurrently during the first 24 hours of treatment. 2
Important Clinical Considerations
The high-dose regimen is necessary because standard-dose amoxicillin (40-45 mg/kg/day) achieves inadequate middle ear fluid concentrations to eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection. 5, 6
Beta-lactamase-producing Haemophilus influenzae is the predominant pathogen in children who fail high-dose amoxicillin therapy, occurring in approximately 62-64% of bacteriologic failures. 6
Despite the emergence of resistant organisms, high-dose amoxicillin maintains good overall clinical efficacy (82% bacteriologic eradication rate) and remains appropriate as first-line empiric therapy. 6