Augmentin Dosing for Otitis Media in a 3-Year-Old, 46 Pounds
For a 3-year-old child weighing 46 pounds (21 kg) with acute otitis media, prescribe high-dose amoxicillin-clavulanate (Augmentin) at 90 mg/kg/day of the amoxicillin component, which equals approximately 1890 mg/day total, divided into two doses of 945 mg each (or practically, 1000 mg twice daily), for 10 days.
Dosing Calculation and Formulation
At 21 kg body weight:
- Total daily dose: 90 mg/kg/day × 21 kg = 1890 mg amoxicillin per day
- Per dose: 945 mg twice daily (can round to 1000 mg for practical dosing)
- Duration: 10 days 1, 2
The high-dose formulation (90 mg/kg/day amoxicillin with 6.4 mg/kg/day clavulanate in 2 divided doses) is specifically recommended by the FDA-approved Augmentin ES-600 formulation 2. Using the ES-600 suspension (600 mg amoxicillin per 5 mL), this child would receive approximately 7.5 mL twice daily.
Why High-Dose Therapy
High-dose amoxicillin-clavulanate is the first-line treatment for this age group because:
- This 3-year-old falls into the moderate-risk category where β-lactamase-producing Haemophilus influenzae and resistant Streptococcus pneumoniae are concerns 1
- The 90 mg/kg/day dosing achieves middle ear fluid concentrations adequate to overcome penicillin-resistant S. pneumoniae (MICs up to 4 mcg/mL) 3, 4
- Clinical studies demonstrate 98.4% bacteriologic eradication of S. pneumoniae and 92.6% eradication of H. influenzae with this regimen 2, 4
When Standard-Dose Would Be Insufficient
The standard lower dose (45 mg/kg/day) would not be appropriate here because:
- Children under 5 years have higher rates of resistant pathogens 3
- The clavulanate component (6.4 mg/kg/day) in the high-dose formulation adequately inhibits all β-lactamase-producing H. influenzae and M. catarrhalis 3, 1
Administration Details
- Give at the start of meals to minimize gastrointestinal side effects and enhance clavulanate absorption 2
- Shake suspension well before each dose
- Refrigerate reconstituted suspension; stable for 10 days 2
- The twice-daily dosing improves compliance compared to three-times-daily regimens while maintaining equivalent efficacy 5
Expected Clinical Response
- Assess improvement within 48-72 hours 1
- If no improvement or worsening occurs, consider treatment failure and switch to ceftriaxone (50 mg/kg IM/IV for 3 days) 1
- Clinical success rates with this regimen are approximately 89-95% at end of therapy 2, 4
Common Pitfalls to Avoid
Do not substitute other Augmentin formulations for ES-600, as they contain different clavulanate concentrations and are not interchangeable 2. The 200 mg/5 mL suspension contains only 28.5 mg clavulanate per 5 mL, while ES-600 contains 42.9 mg per 5 mL—this difference is critical for adequate β-lactamase inhibition.
Do not use standard-dose amoxicillin alone (without clavulanate) in this age group unless the child has no risk factors (no recent antibiotics, no daycare attendance, fully immunized) 3, 1. This 3-year-old's age alone makes high-dose amoxicillin-clavulanate more appropriate than amoxicillin monotherapy.
The most common side effect is diarrhea (protocol-defined diarrhea occurs in 11-13% of patients), though this is generally mild and does not require discontinuation 2.