Therapeutic Dose of Co-Amoxiclav 457/5 for Pediatric UTI
For a 9-year-old child with uncomplicated UTI and normal renal function, the therapeutic dose of co-amoxiclav (amoxicillin-clavulanate) is 20-40 mg/kg/day of the amoxicillin component divided into 3 doses, which translates to approximately 5 mL of the 250/62 suspension three times daily for most children in this age group. 1, 2
Standard Dosing Algorithm
For Uncomplicated UTI in 9-Year-Old
The American Academy of Pediatrics recommends 20-40 mg/kg/day of amoxicillin component divided into 3 doses for urinary tract infections. 1 For a typical 9-year-old child (approximately 25-30 kg), this translates to:
- 5 mL of 250/62 suspension three times daily (providing approximately 250 mg amoxicillin per dose, or 750 mg total daily) 2
- This provides approximately 25-30 mg/kg/day, which falls within the recommended range 1
Treatment Duration
The total course of therapy should be 7-14 days for urinary tract infections. 1 The American Academy of Pediatrics guideline states that while they attempted to identify a single preferred duration, direct comparison data for 7,10, and 14 days were not found, but courses of 1-3 days are inferior. 1
Treatment should continue for a minimum of 48-72 hours beyond when the patient becomes asymptomatic or evidence of bacterial eradication is obtained. 1, 3
Critical Dosing Considerations
Verify Suspension Concentration
Always verify whether you are using 125/31 or 250/62 suspension before calculating volume, as this is a common source of dosing errors. 2 The 250/62 formulation is specifically indicated for children over 6 years of age. 2
When to Use Higher Doses
Higher doses (45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours) are reserved for severe infections or lower respiratory tract infections, NOT for uncomplicated UTI. 1, 3 For uncomplicated UTI in a 9-year-old with normal renal function, the standard 20-40 mg/kg/day regimen is appropriate. 1
Evidence Supporting This Dosing
Guideline-Based Recommendations
The American Academy of Pediatrics guideline for UTI management specifically lists amoxicillin-clavulanate at 20-40 mg/kg/day in 3 doses as an appropriate oral treatment option for urinary tract infections in children. 1 This is the primary guideline recommendation that should guide therapy.
Clinical Research Support
Research studies support the efficacy of this dosing range:
- A study of 42 children with UTI showed 96% clearance rate using 40 mg/kg/day divided twice daily for 5 days. 4
- Another study of 32 children demonstrated 80% favorable response with amoxicillin-clavulanate, including successful treatment of amoxicillin-resistant organisms. 5
- Long-term therapy studies used 40 mg/kg/day for initial sterilization followed by prophylactic dosing, achieving 90% success rates. 6
Common Pitfalls to Avoid
Do Not Underdose
An 80 mg total daily dose would be grossly inadequate for a 9-year-old child and would lead to treatment failure and promotion of antimicrobial resistance. 2 The minimum effective dose for a child this age is approximately 500-750 mg total daily (amoxicillin component). 2
Avoid Agents That Don't Achieve Systemic Concentrations
Nitrofurantoin should NOT be used for febrile UTIs or suspected pyelonephritis, as it does not achieve therapeutic concentrations in the bloodstream or renal parenchyma. 1 While this patient has uncomplicated UTI, if there is any concern for upper tract involvement, amoxicillin-clavulanate is the appropriate choice.
Consider Local Resistance Patterns
It is essential to know local patterns of susceptibility of coliforms to antimicrobial agents, as there is substantial geographic variability. 1 If local resistance to amoxicillin-clavulanate exceeds 20%, consider alternative agents or adjust empiric therapy based on culture results.
Renal Function Considerations
For this patient with normal renal function, no dose adjustment is necessary. 3 However, if glomerular filtration rate were less than 30 mL/min, dosing would need to be reduced to 500 mg or 250 mg every 12-24 hours depending on severity. 3