Amoxicillin-Clavulanate Dosing for a 33 kg Child
For a 33 kg child, prescribe amoxicillin-clavulanate 90 mg/kg/day of the amoxicillin component (2970 mg/day total amoxicillin) divided into 2 doses, which equals approximately 1485 mg per dose twice daily. 1
Dosing Framework
The appropriate dose depends critically on the severity and type of infection:
For Moderate-to-Severe Infections or High-Risk Situations
- High-dose regimen: 90 mg/kg/day of amoxicillin component in 2 divided doses 2, 1
- For 33 kg: 1485 mg amoxicillin twice daily (total 2970 mg/day)
- This provides 6.4 mg/kg/day of clavulanate 2
Use high-dose for:
- Acute bacterial sinusitis with moderate-to-severe symptoms 2
- Children <2 years old 2
- Recent antibiotic use (within 30 days) 2
- Daycare attendance 2
- Community-acquired pneumonia requiring hospitalization 3
- Areas with high penicillin-resistant S. pneumoniae (>10% resistance) 2
For Less Severe Infections
- Standard-dose regimen: 45 mg/kg/day in 2 divided doses 1
- For 33 kg: 742.5 mg amoxicillin twice daily (total 1485 mg/day)
- Use for uncomplicated infections in low-risk children 2
Practical Prescribing Considerations
Formulation Selection
Since this child weighs <40 kg, use pediatric suspension formulations 1:
- 400 mg/57 mg per 5 mL suspension is preferred for high-dose therapy
- For high-dose (1485 mg): Give 18.5 mL twice daily
- For standard-dose (742.5 mg): Give 9.3 mL twice daily
Critical Dosing Pitfall
Children weighing >20 kg frequently receive subtherapeutic doses because clinicians inappropriately cap doses at "adult maximums" 4. At 33 kg, this child should receive the calculated weight-based dose (up to 2970 mg/day for high-dose therapy), which may exceed typical adult doses of 1500-1750 mg/day. This is appropriate and necessary 5, 4.
Administration
- Give at the start of meals to enhance clavulanate absorption and minimize GI side effects 1
- The twice-daily regimen causes significantly less diarrhea than three-times-daily dosing 1
- Shake suspension well before each dose 1
Pathogen-Specific Guidance
For β-lactamase-producing H. influenzae (common in respiratory infections):
- Amoxicillin-clavulanate at 45 mg/kg/day (standard) or 90 mg/kg/day (high-dose) in 2 doses 3
For penicillin-resistant S. pneumoniae:
- High-dose amoxicillin component (80-90 mg/kg/day) achieves adequate sinus/middle ear fluid concentrations to overcome resistance 2
Duration
- Acute otitis media: 10 days 1
- Acute bacterial sinusitis: 10-14 days (or 7 days after symptom resolution) 2
- Community-acquired pneumonia: Typically 7-10 days 3
The key decision point is infection severity and risk factors—not arbitrary adult dose maximums.