Recommended Amoxicillin Dosage for 14-Year-Old with Ear Infection
For a 14-year-old with acute otitis media (ear infection), prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses (every 12 hours) for 5-7 days, with a maximum adult dose of 875 mg twice daily. 1, 2
Dosing Algorithm
Standard Dosing (First-Line)
- Weight <40 kg: 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 2
- Weight ≥40 kg: 875 mg every 12 hours OR 500 mg every 8 hours 2
High-Dose Considerations
The FDA-approved dosing for ear/nose/throat infections in adolescents supports both standard and severe infection dosing 2. The 2013 AAP guidelines specifically recommend high-dose amoxicillin (80-90 mg/kg/day) as first-line therapy, which translates to the 875 mg twice daily regimen for most 14-year-olds 1.
Duration of Treatment
- Standard duration: 5-7 days is appropriate for uncomplicated acute otitis media 1
- Continue treatment for minimum 48-72 hours beyond symptom resolution 2
When to Modify First-Line Therapy
Switch to amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component) if:
- Amoxicillin taken within previous 30 days 1
- Concurrent purulent conjunctivitis (otitis-conjunctivitis syndrome) 1
- Treatment failure after 48-72 hours 1
Penicillin Allergy Alternatives
If true penicillin allergy exists:
- Cefdinir: 14 mg/kg/day in 1-2 doses 1
- Cefuroxime: 30 mg/kg/day in 2 doses 1
- Ceftriaxone: 50 mg IM/IV for 1-3 days 1
Note: Cross-reactivity between penicillins and cephalosporins is lower than historically reported (<10%), making cephalosporins reasonable alternatives 1.
Evidence Supporting This Recommendation
The 2013 AAP/AAFP guidelines provide the most authoritative guidance for acute otitis media management 1. High-dose amoxicillin remains first-line despite increasing beta-lactamase-producing organisms because:
Clinical efficacy remains excellent: Recent data show treatment failure rates of only 5.4% with amoxicillin, with no difference between patients with or without beta-lactamase-producing bacteria 3, 4
Superior to alternatives: A large retrospective study of over 1 million children found combined failure and recurrence rates were lowest for amoxicillin (1.7%) compared to amoxicillin-clavulanate (11.3%), cefdinir (10.0%), and azithromycin (9.8%) 4
Twice-daily dosing improves adherence: The 875 mg twice-daily regimen is as effective as three-times-daily dosing and associated with fewer administration difficulties 5
Common Pitfalls to Avoid
- Don't underdose: Standard-dose amoxicillin (40-45 mg/kg/day) is no longer recommended as first-line for acute otitis media 1
- Don't automatically use amoxicillin-clavulanate: Reserve this for specific indications (recent amoxicillin use, concurrent conjunctivitis, or treatment failure) to minimize adverse effects and resistance 1
- Don't prescribe azithromycin as first-line: It has inferior efficacy compared to amoxicillin 1, 4