Co-Amoxiclav Dosing for a 9-Year-Old, 25kg Child
For a 9-year-old male weighing 25kg using the 457mg/5ml preparation (which contains 400mg amoxicillin/57mg clavulanate per 5ml), give 5ml twice daily for standard infections, or 5ml three times daily for severe infections. 1
Dosing Calculation and Rationale
The standard pediatric dose of co-amoxiclav is 45 mg/kg/day of the amoxicillin component divided into 2-3 doses, or 90 mg/kg/day in 2 doses for high-dose therapy. 1, 2
For this 25kg child:
- Standard dose: 45 mg/kg/day = 1,125 mg/day of amoxicillin component 1
- High dose: 90 mg/kg/day = 2,250 mg/day of amoxicillin component 1
With the 457mg/5ml preparation (400mg amoxicillin per 5ml), this translates to:
- Standard dosing: 5ml twice daily (800mg/day total) for mild-moderate infections 1, 2
- High-dose regimen: 5ml three times daily (1,200mg/day total) for severe infections or resistant organisms 3, 1
Age-Based Dosing Guidelines
According to British Thoracic Society guidelines, children aged 7-12 years should receive 5ml of 250/62 suspension three times daily for standard infections. 3 However, the 457mg/5ml preparation you have is a higher-strength formulation specifically designed for twice-daily dosing. 1, 2
The 457mg/5ml (400/57) formulation achieves similar pharmacokinetic profiles with twice-daily dosing as the traditional 250/62 formulation given three times daily. 4
When to Use High-Dose Therapy
High-dose co-amoxiclav (90 mg/kg/day) is indicated when any of the following risk factors are present: 1, 2
- Age <2 years
- Daycare attendance
- Recent antibiotic use (within 30 days)
- Incomplete Haemophilus influenzae type b vaccination
- Geographic area with high pneumococcal resistance (>10%)
- Moderate to severe illness
- Concurrent purulent otitis media
For this 9-year-old without specified risk factors, standard dosing of 5ml twice daily is appropriate for most infections. 1, 2
Duration of Therapy
The typical treatment duration is 7-10 days for most respiratory and soft tissue infections, though may extend to 14 days depending on clinical response. 3, 2
Clinical improvement should be evident within 48-72 hours; if no improvement or worsening occurs, reassess the diagnosis and consider alternative therapy. 1, 2
Critical Dosing Considerations
The 457mg/5ml preparation provides a 14:1 ratio of amoxicillin to clavulanate (400mg/57mg per 5ml), which minimizes gastrointestinal side effects while maintaining efficacy. 1
Always verify the suspension concentration before dispensing, as different formulations (125/31,250/62,400/57) require different volumes to achieve the same dose. 1
Administer with food to enhance clavulanate absorption and reduce gastrointestinal side effects. 4
Common Pitfalls to Avoid
Do not underdose in areas with high penicillin-resistant Streptococcus pneumoniae prevalence—use the high-dose regimen (5ml three times daily) when resistance is suspected. 1, 2
Avoid using subtherapeutic doses, as they fail to achieve adequate tissue concentrations and promote antimicrobial resistance. 1
The maximum single dose should not exceed 2 grams of amoxicillin component regardless of weight. 1