Amoxicillin Dosing for Unilateral Ear Infection in Children
For pediatric patients with unilateral acute otitis media, prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses daily for 10 days, provided the child has not received amoxicillin in the past 30 days, does not have concurrent purulent conjunctivitis, and is not allergic to penicillin. 1
Treatment Decision Algorithm
Step 1: Determine if Antibiotics Are Indicated
For children 6-23 months old with unilateral AOM:
- Either prescribe antibiotics OR offer observation with close follow-up based on shared decision-making with parents, if the infection is non-severe (mild ear pain <48 hours and temperature <39°C/102.2°F) 1
For children ≥24 months old with unilateral AOM:
- Either prescribe antibiotics OR offer observation with close follow-up based on shared decision-making with parents, if non-severe 1
Always prescribe antibiotics immediately if:
- Moderate to severe bulging of the tympanic membrane 1
- New onset of ear drainage (otorrhea) 1
- Severe symptoms (severe ear pain >48 hours or temperature ≥39°C/102.2°F) 1
Step 2: Select the Appropriate Antibiotic
First-line choice: High-dose amoxicillin (80-90 mg/kg/day in 2 divided doses) when: 1, 2
- Child has NOT received amoxicillin in the past 30 days
- No concurrent purulent conjunctivitis
- No penicillin allergy
Use high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate in 14:1 ratio, given in 2 divided doses) when: 1, 3
- Child received amoxicillin in the previous 30 days
- Concurrent purulent conjunctivitis present
- History of recurrent AOM unresponsive to amoxicillin
Rationale for High-Dose Therapy
High-dose amoxicillin achieves middle ear fluid concentrations that exceed the minimum inhibitory concentration for approximately 87% of Streptococcus pneumoniae isolates, including intermediately resistant strains 2, 4. Standard dosing (40-45 mg/kg/day) is inadequate to effectively eradicate resistant S. pneumoniae, particularly during viral coinfection 4. The high-dose regimen provides superior bacteriologic efficacy, with 92% eradication of S. pneumoniae compared to lower rates with standard dosing 5.
Treatment Duration and Monitoring
- Standard treatment duration: 10 days 3, 2
- Reassess at 48-72 hours: If symptoms worsen or fail to improve, this indicates treatment failure 1
Management of Treatment Failure (No Improvement at 48-72 Hours)
If initially treated with amoxicillin:
- Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin with 6.4 mg/kg/day of clavulanate in 2 divided doses) 1, 3, 2
If initially treated with amoxicillin-clavulanate:
Critical Pitfalls to Avoid
Underdosing in heavier children: Primary care physicians frequently prescribe significantly lower-than-recommended doses in older and heavier children 6. The dose should always be calculated as 80-90 mg/kg/day regardless of weight, though the maximum single dose is 2000 mg 3.
Using incorrect amoxicillin-clavulanate formulations: Only use the 14:1 ratio formulation (90 mg/kg amoxicillin with 6.4 mg/kg clavulanate), as older formulations with higher clavulanate ratios cause significantly more diarrhea 1, 3.
Prescribing amoxicillin when recent exposure exists: If the child received amoxicillin within 30 days, bacterial resistance is more likely, and amoxicillin-clavulanate should be used instead 1, 3.
Inadequate coverage for β-lactamase producers: Approximately 34% of Haemophilus influenzae isolates produce β-lactamase and are resistant to amoxicillin alone 5. When treatment fails, 64% of bacteriologic failures involve β-lactamase-positive H. influenzae 5.
Penicillin Allergy Alternatives
For children with penicillin allergy, alternative first-line options include 1:
- Cefdinir (14 mg/kg/day in 1-2 doses)
- Cefuroxime (30 mg/kg/day in 2 divided doses)
- Cefpodoxime (10 mg/kg/day in 2 divided doses)
Cross-reactivity between penicillins and second/third-generation cephalosporins is negligible due to distinct chemical structures, making these safe alternatives 1.