Amoxicillin Dosing for Acute Otitis Media in a 3-Year-Old
For a 3-year-old child with acute otitis media, prescribe amoxicillin 80-90 mg/kg/day divided into 2 doses for 5 days. 1
Dose Calculation
- Calculate the total daily dose based on the child's weight: multiply weight in kg by 80-90 mg 1
- For example, a 15 kg child would receive 1200-1350 mg total per day, divided into two doses of 600-675 mg each 1
- Using the 125 mg/5 mL suspension, this translates to approximately 24-27 mL per dose, given twice daily 1
Treatment Duration
- 5 days is the recommended duration for children over 2 years of age with uncomplicated acute otitis media 2
- Children under 2 years require 8-10 days of treatment, but at age 3, the shorter 5-day course is appropriate 2
Rationale for High-Dose Amoxicillin
- High-dose amoxicillin (80-90 mg/kg/day) is first-line therapy because it provides effective coverage against drug-resistant Streptococcus pneumoniae while maintaining safety, low cost, acceptable taste, and narrow microbiologic spectrum 1
- This dosing achieves bacteriologic eradication in 92% of S. pneumoniae cases, including penicillin-nonsusceptible strains 3
- The predominant pathogens in this age group are S. pneumoniae, H. influenzae, and Moraxella catarrhalis 2
Twice-Daily vs Three-Times-Daily Dosing
- Twice-daily dosing is as effective as three-times-daily and offers better adherence for caregivers 4
- Twice-daily regimens are associated with fewer family-perceived problems with dosing schedules (31% vs 5.8% reporting difficulties) 4
When to Switch Antibiotics
Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) if: 1
- The child received amoxicillin in the previous 30 days
- Concurrent purulent conjunctivitis is present (suggests H. influenzae)
- No improvement after 48-72 hours of treatment
Reassessment Criteria
- Evaluate the patient at 48-72 hours if symptoms fail to improve 1
- Treatment failure is defined as worsening condition, persistence of symptoms beyond 48 hours, or recurrence within 4 days of completing therapy 2
- Beta-lactamase-producing H. influenzae is the predominant pathogen in treatment failures (64% of bacteriologic failures) 3
Important Caveats
- Pain management must be addressed concurrently during the first 24 hours of treatment 1
- For children with marked symptoms (high fever, intense earache), antibiotic therapy is strongly recommended 2
- If the child has received inadequate H. influenzae type b vaccination (<3 doses) or has concurrent purulent otitis media, consider amoxicillin-clavulanate as first-line therapy 2