Amoxicillin Dosing for Acute Otitis Media in a 22.6 kg Child
For this 22.6 kg child with acute otitis media, administer 10 mL of amoxicillin 400 mg/5 mL suspension twice daily (providing 1800 mg/day total, which equals 80 mg/kg/day). 1, 2
Recommended Dosing Calculation
- Target dose: 80-90 mg/kg/day divided into 2 doses 1, 2
- For 22.6 kg patient: 1808-2034 mg/day total
- Practical dosing: 900 mg twice daily = 1800 mg/day (80 mg/kg/day)
Available Suspension Formulations and Volume
Using 400 mg/5 mL suspension (most concentrated option):
- 10 mL twice daily provides 800 mg per dose (1600 mg/day = 71 mg/kg/day)
- 11 mL twice daily provides 880 mg per dose (1760 mg/day = 78 mg/kg/day)
- 11.25 mL twice daily provides 900 mg per dose (1800 mg/day = 80 mg/kg/day) 3
The most practical approach is 11 mL twice daily, which delivers approximately 78 mg/kg/day and falls within the recommended 80-90 mg/kg/day range. 1
Alternatively, using 250 mg/5 mL suspension:
- 18 mL twice daily provides 900 mg per dose (1800 mg/day = 80 mg/kg/day) 3
When to Use Amoxicillin-Clavulanate Instead
Switch to high-dose amoxicillin-clavulanate (90 mg/6.4 mg per kg per day) if: 1
- Child received amoxicillin in the previous 30 days 1
- Concurrent purulent conjunctivitis is present 1
- Desire for β-lactamase coverage (H. influenzae, M. catarrhalis) 1
For amoxicillin-clavulanate at 90 mg/6.4 mg per kg per day in this 22.6 kg patient:
- Total daily dose: 2034 mg amoxicillin component
- Using 600 mg/42.9 mg per 5 mL suspension: 8.5 mL twice daily 3
Treatment Duration
- Children ≥2 years: 5-7 days is typically sufficient 1, 2
- Children <2 years: 10 days recommended 1, 2
- The FDA label and traditional guidelines support 10-day courses for acute otitis media 3
Clinical Pearls and Pitfalls
High-dose amoxicillin (80-90 mg/kg/day) is superior to standard-dose (40-45 mg/kg/day) for:
- Eradicating drug-resistant S. pneumoniae (92% eradication rate with high-dose) 4
- Achieving adequate middle ear fluid concentrations, particularly with viral co-infection 5
Common failure scenario: β-lactamase-producing H. influenzae accounts for 64% of bacteriologic failures with amoxicillin monotherapy 4. If treatment fails after 48-72 hours, switch to amoxicillin-clavulanate 1.
Avoid these errors:
- Do NOT substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet—clavulanate content differs 3
- Do NOT use 250 mg/125 mg tablets interchangeably with 250 mg/62.5 mg chewable tablets 3
- Standard-dose amoxicillin (40-45 mg/kg/day) is inadequate in areas with drug-resistant S. pneumoniae 5, 4
Reassessment
Reassess if symptoms worsen or fail to improve within 48-72 hours. 1, 2 At that point, consider switching to amoxicillin-clavulanate or alternative antibiotics based on local resistance patterns 1.