Co-Amoxiclav Dosing in Pediatric Patients
For most pediatric patients with acute infections, use high-dose co-amoxiclav at 90 mg/kg/day of the amoxicillin component with 6.4 mg/kg/day of clavulanate, divided into two daily doses (14:1 ratio formulation). 1
Age-Based Oral Dosing Regimens
Standard Suspension Dosing
- <1 year (1-12 months): 2.5 ml three times daily of 125/31 suspension 2
- 1-6 years: 5 ml three times daily of 125/31 suspension 2
- 7-12 years: 5 ml three times daily of 250/62 suspension 2
- 12-18 years: 1 tablet (250/125) three times daily 2
High-Dose Regimen (Preferred for Resistant Organisms)
The high-dose formulation provides superior coverage against penicillin-resistant Streptococcus pneumoniae and β-lactamase-producing organisms 1. This regimen is specifically indicated for:
- Children <2 years of age 1
- Recent antibiotic use within 30 days 2, 1
- Daycare attendance 1
- Concurrent conjunctivitis 2
- Moderate to severe illness 1
- Incomplete Haemophilus influenzae type b vaccination (<3 injections) 1
The 90 mg/kg/day amoxicillin component achieves middle ear fluid concentrations adequate to overcome resistant pathogens, while standard 40-45 mg/kg/day dosing leads to treatment failure with resistant organisms 1, 3.
Intravenous Dosing
- All ages: 30 mg/kg three times daily IV 2
Clinical Pharmacology Considerations
Dosing Rationale
High-dose amoxicillin (80-90 mg/kg/day) exceeds the minimum inhibitory concentration for intermediately resistant S. pneumoniae (penicillin MICs 0.12-1.0 μg/mL) and many highly resistant serotypes (penicillin MICs ≥2 μg/mL) for longer periods during the dosing interval 2. The 14:1 ratio formulation (90/6.4 mg/kg/day) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 2, 1.
Maximum Dosing
The maximum single dose is 2 grams per dose regardless of weight 1.
Alternative Dosing for Specific Infections
For β-lactamase-producing H. influenzae in respiratory tract infections, either 45 mg/kg/day in 3 doses or 90 mg/kg/day in 2 doses is acceptable 1. However, the twice-daily high-dose regimen is preferred for improved compliance and equivalent efficacy 1.
Duration of Therapy
Treatment courses should be 10 days for most pediatric infections 1, or continue for 7 days after the patient becomes free of signs and symptoms 1.
Common Pitfalls to Avoid
Using standard doses (40-45 mg/kg/day) when high-dose therapy is indicated will result in treatment failure with resistant organisms 1. This is particularly problematic in areas with >10% prevalence of penicillin-resistant S. pneumoniae 1.
The older three-times-daily dosing regimens from pandemic influenza guidelines 2 are now superseded by twice-daily high-dose formulations that provide better compliance and equivalent or superior efficacy 1.
Serum levels of amoxicillin increase linearly with dose, and the difference in adverse effects between lower and higher doses is generally negligible 1. Common adverse effects include diarrhea, nausea, vomiting, and rash, but these are less frequent with the twice-daily high-dose formulation 1.