Amoxicillin for a 12-Year-Old with Otitis Media
For a 12-year-old with acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses (maximum 500 mg per dose) as first-line therapy. 1, 2, 3
First-Line Treatment Recommendation
High-dose amoxicillin (80-90 mg/kg/day in 2 divided doses) is the standard first-line antibiotic for acute otitis media in children and adolescents, including 12-year-olds. 1, 3
This dosing achieves middle ear fluid concentrations that exceed the minimum inhibitory concentration for intermediately resistant Streptococcus pneumoniae for a longer duration of the dosing interval. 2, 4
Amoxicillin remains the preferred agent due to its proven efficacy, safety profile, narrow microbiologic spectrum, low cost, and acceptable taste. 1, 3
When to Use Amoxicillin-Clavulanate Instead
Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate in 2 divided doses) in these specific situations: 1, 3
- The child received amoxicillin within the past 30 days
- Concurrent purulent conjunctivitis is present
- History of recurrent AOM unresponsive to amoxicillin
- Need for coverage against β-lactamase-producing Haemophilus influenzae or Moraxella catarrhalis
The 14:1 ratio formulation (amoxicillin to clavulanate) is preferred as it causes significantly less diarrhea than other ratios. 2, 5
Treatment Duration
For children 2 years and older with uncomplicated AOM, a 10-day course remains the standard recommendation based on the evidence, though some guidelines suggest shorter courses may be considered in select cases. 1, 5
Monitoring and Treatment Failure
Reassess within 48-72 hours if symptoms worsen or fail to improve. 1, 3
If treatment fails after 48-72 hours on amoxicillin, switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component in 2 divided doses). 1, 3
Alternatively, consider ceftriaxone 50 mg/kg IM or IV for 3 days for treatment failures. 3
Bacteriologic failure with high-dose amoxicillin occurs in approximately 28% of patients, with β-lactamase-producing H. influenzae being the predominant pathogen in treatment failures. 4
Pain Management
- Address pain management early in the course regardless of antibiotic choice, as this is a critical component of AOM treatment. 1, 2
Important Clinical Caveats
The every 12-hour dosing regimen is preferred over every 8-hour dosing as it is associated with significantly less diarrhea and improves compliance. 5
High-dose amoxicillin achieves bacteriologic eradication in 92% of S. pneumoniae isolates (including penicillin-nonsusceptible strains with amoxicillin MIC ≤2.0 mcg/mL) and 84% of β-lactamase-negative H. influenzae. 4
Only 62% of β-lactamase-positive H. influenzae are eradicated with amoxicillin monotherapy, which is why amoxicillin-clavulanate is recommended for treatment failures. 4
For patients weighing 40 kg or more, adult dosing recommendations apply (typically 500 mg every 12 hours or 875 mg every 12 hours for more severe infections). 5