What is the dose of co-amoxiclav (amoxicillin/clavulanic acid) 457 mg/5ml syrup to be given to a 7-year-old female weighing 18 kilograms every 8 hours?

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Co-amoxiclav Dosing for 7-Year-Old Female, 18 kg

For this 7-year-old child weighing 18 kg, give 5 ml of co-amoxiclav 250/62 suspension three times daily (every 8 hours). 1, 2

Dosing Calculation and Rationale

Age-Based Guideline Recommendation

  • Children aged 7-12 years should receive 5 ml of 250/62 suspension three times daily, which is the standard regimen for this age group 1, 2
  • This age-based dosing is specifically recommended for pediatric patients in pandemic influenza guidelines and general pediatric infectious disease management 1

Weight-Based Verification

  • The 457 mg/5ml formulation you mentioned appears to be a high-dose formulation (approximately 400 mg amoxicillin + 57 mg clavulanate per 5 ml) 3, 4
  • For standard dosing (45 mg/kg/day): 18 kg × 45 mg/kg/day = 810 mg/day ÷ 3 doses = 270 mg per dose 5, 2
  • For high-dose regimen (90 mg/kg/day): 18 kg × 90 mg/kg/day = 1620 mg/day ÷ 2 doses = 810 mg per dose 5, 6, 2

Practical Dosing with 457 mg/5ml Suspension

If using the 457 mg/5ml formulation (high-dose formulation):

  • For standard three-times-daily dosing: Give approximately 3 ml every 8 hours (provides ~274 mg amoxicillin per dose, total ~822 mg/day) 2
  • For high-dose twice-daily dosing: Give approximately 4.5 ml every 12 hours (provides ~411 mg amoxicillin per dose, total ~822 mg/day) 5, 2

Clinical Context Matters

Standard dosing (45 mg/kg/day in 3 divided doses) is appropriate for: 2

  • Uncomplicated respiratory tract infections
  • Urinary tract infections
  • Skin and soft tissue infections

High-dose regimen (90 mg/kg/day in 2 divided doses) is indicated for: 6, 2

  • Areas with high penicillin-resistant Streptococcus pneumoniae prevalence (>10%)
  • Children <2 years with acute otitis media
  • Recent antibiotic use within past 30 days
  • Daycare attendance
  • Moderate to severe illness
  • Incomplete Haemophilus influenzae type b vaccination

Maximum Dose Considerations

  • The maximum daily dose should not exceed 4000 mg of amoxicillin component regardless of weight 5, 6
  • For this 18 kg child, calculated doses are well below the maximum threshold 5

Important Clinical Caveats

  • The 14:1 ratio formulation (high-dose) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 2
  • Children on appropriate antibiotic therapy should show clinical improvement within 48-72 hours; if not, reevaluation is necessary 6
  • Complete the full course of antibiotics as prescribed, typically 7-10 days for most pediatric infections 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Amoxicillin-Clavulanate Dosing in Pediatric Patients

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Pediatric UTI Treatment Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Amoxicillin Dosing Guidelines for Pediatric Patients

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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