Amoxicillin Dosing for Acute Otitis Media in a 19-Month-Old
Prescribe high-dose amoxicillin at 80-90 mg/kg/day divided into 2 doses daily for 10 days. 1, 2
Exact Dosing Instructions
Calculate the dose:
- Determine the child's weight in kilograms
- Multiply weight (kg) × 90 mg = total daily dose
- Divide the total daily dose by 2 = dose per administration
- Give this calculated dose twice daily (every 12 hours) 2, 3
Example calculation:
- For a 12 kg child: 12 kg × 90 mg/kg = 1,080 mg total daily dose
- 1,080 mg ÷ 2 = 540 mg per dose
- Give 540 mg twice daily for 10 days
Treatment duration:
- Treat for exactly 10 days in children under 2 years of age 2
Why High-Dose Amoxicillin?
High-dose amoxicillin (80-90 mg/kg/day) is the standard first-line therapy recommended by the American Academy of Pediatrics for acute otitis media in this age group. 1, 2
- High-dose therapy achieves adequate middle ear fluid concentrations to cover Streptococcus pneumoniae (including intermediately resistant strains), Haemophilus influenzae, and Moraxella catarrhalis 2
- Approximately 87% of S. pneumoniae isolates are susceptible to high-dose amoxicillin 2
- The twice-daily dosing regimen has equivalent efficacy to three-times-daily dosing and improves adherence 3
When NOT to Use Standard Amoxicillin
Switch to high-dose amoxicillin-clavulanate (90 mg/kg/day of amoxicillin component, using the 14:1 ratio formulation) if: 1, 2
- The child received amoxicillin in the previous 30 days
- Concurrent purulent conjunctivitis is present
- History of recurrent AOM unresponsive to amoxicillin
Follow-Up and Treatment Failure
Reassess the patient if symptoms worsen or fail to improve within 48-72 hours: 1, 2
- Clinical improvement should be evident within 48-72 hours 2
- If no improvement occurs, switch to amoxicillin-clavulanate or consider ceftriaxone 2
- The predominant pathogens in treatment failures are beta-lactamase-producing organisms, particularly H. influenzae 4
Important Prescribing Details
For liquid amoxicillin formulations:
- Most suspensions come in concentrations of 200 mg/5 mL, 250 mg/5 mL, or 400 mg/5 mL
- Choose the concentration that minimizes volume per dose to improve adherence 3
- Instruct caregivers to shake well before each dose and refrigerate after reconstitution
- Provide clear written instructions with the exact mL volume to administer twice daily
Common Pitfalls to Avoid
- Do not use standard-dose amoxicillin (40-45 mg/kg/day) for empiric treatment, as it provides inadequate coverage for resistant S. pneumoniae 1, 2
- Do not prescribe three-times-daily dosing when twice-daily dosing is equally effective and improves adherence 3
- Do not use single-dose therapy, which has a significantly higher failure rate 5
- Do not forget pain management regardless of antibiotic choice 2