Amoxicillin Dosing for Pediatric Ear Infections
The recommended dose of amoxicillin for pediatric patients with acute otitis media is high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses daily for 10 days. 1, 2, 3
Weight-Based Dosing Calculations
For practical implementation, the following weight-based calculations apply:
- 10 kg child: 800-900 mg total daily dose = 400-450 mg twice daily 2
- 15 kg child: 1200-1350 mg total daily dose = 600-675 mg twice daily 2
- 20 kg child: 1600-1800 mg total daily dose = 800-900 mg twice daily 2
- 25 kg child: 2000-2250 mg total daily dose = 1000-1125 mg twice daily 2
Rationale for High-Dose Regimen
High-dose amoxicillin is specifically designed to achieve middle ear fluid concentrations that exceed the minimum inhibitory concentration for penicillin-resistant and intermediately-resistant Streptococcus pneumoniae. 2, 3
- High-dose amoxicillin achieves middle ear fluid levels sufficient to eradicate approximately 87% of S. pneumoniae isolates, including intermediately resistant strains, compared to only 83% with standard dosing 2, 3
- This dosing strategy provides superior bacteriologic and clinical efficacy against the most common resistant pathogens causing acute otitis media 2, 3
Treatment Duration
- Complete the full 10-day course of amoxicillin regardless of symptom improvement 2, 3
- Administer amoxicillin at the start of a meal to minimize gastrointestinal intolerance 4
When to Switch to Amoxicillin-Clavulanate
Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate in 2 divided doses) in these specific situations:
- Child received amoxicillin within the previous 30 days 1, 2, 3
- Concurrent purulent conjunctivitis (otitis-conjunctivitis syndrome) 1, 2, 3
- No clinical improvement within 48-72 hours of initiating amoxicillin therapy 2, 3
- Suspected β-lactamase-producing organisms (H. influenzae or M. catarrhalis) 2, 3
Special Populations
Infants Under 6 Months
- Immediate antibiotic therapy is indicated for all infants under 6 months with acute otitis media 1
- Use the same high-dose amoxicillin regimen (80-90 mg/kg/day divided twice daily) 2, 3
Infants Under 3 Months
- Maximum recommended dose is 30 mg/kg/day divided every 12 hours due to incompletely developed renal function 4
Severe Renal Impairment
- For GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 4
- For GFR <10 mL/min: 500 mg or 250 mg every 24 hours 4
- Patients with GFR <30 mL/min should NOT receive the 875 mg dose formulation 4
Penicillin Allergy Alternatives
- Non-anaphylactic reactions: Use cefdinir (14 mg/kg/day), cefuroxime (30 mg/kg/day), or cefpodoxime (10 mg/kg/day) 2
- Type I hypersensitivity/anaphylaxis: Use azithromycin or clarithromycin, though these have inferior bacteriologic efficacy against resistant S. pneumoniae 2
Critical Pitfalls to Avoid
- Do not use standard-dose amoxicillin (40-45 mg/kg/day) as it is inadequate to effectively eradicate resistant S. pneumoniae, particularly during viral coinfection 5
- Reevaluate within 48-72 hours if no clinical improvement occurs, as this indicates potential treatment failure requiring escalation to amoxicillin-clavulanate 2, 3
- Viral coinfection reduces amoxicillin middle ear fluid penetration, making high-dose therapy even more critical in these cases 5
- Research demonstrates that amoxicillin middle ear fluid concentrations are lowest in virus-infected children (2.7 μg/ml) compared to bacterial-only infection (5.7 μg/ml), supporting the need for high-dose therapy 5