What is the recommended dose of Augmentin (amoxicillin/clavulanate) in mL for a 12-year-old patient weighing 35 kg with normal renal function and no history of allergy to penicillins?

Augmentin Dosing for a 12-Year-Old Weighing 35 kg

For a 12-year-old patient weighing 35 kg, the recommended dose of Augmentin depends on the severity and type of infection, but for most respiratory tract infections, administer 45 mg/kg/day of the amoxicillin component divided into 2 doses, which equals approximately 787.5 mg per dose (roughly 8 mL of the 400 mg/5 mL suspension twice daily). 1

Dosing Algorithm Based on Clinical Indication

For Mild to Moderate Respiratory Infections

• Standard dose: 45 mg/kg/day of amoxicillin component divided every 12 hours 1, 2
• For 35 kg patient: 45 × 35 = 1,575 mg/day total, or 787.5 mg per dose twice daily
• Using 400 mg/5 mL suspension: approximately 10 mL twice daily
• Using 250 mg/5 mL suspension: approximately 16 mL twice daily

For Severe Infections or High Pneumococcal Resistance Areas

• High-dose regimen: 90 mg/kg/day of amoxicillin component divided every 12 hours 1, 2
• For 35 kg patient: 90 × 35 = 3,150 mg/day total, or 1,575 mg per dose twice daily
• This dosing is specifically indicated for:
  • Community-acquired pneumonia in areas with >10% penicillin-resistant S. pneumoniae 1
  • Recent antibiotic exposure within past 30 days 1
  • Daycare attendance 1
  • Children <2 years (not applicable here) 1
  • Severe infections requiring hospitalization 1

For β-Lactamase-Producing Organisms

• The Infectious Diseases Society of America recommends either 45 mg/kg/day in 3 doses OR 90 mg/kg/day in 2 doses for β-lactamase producing H. influenzae 1
• For 35 kg patient with recent antibiotic exposure: 1,575 mg twice daily (90 mg/kg/day regimen) 1

Treatment Duration and Monitoring

• Standard duration: 7-10 days for most respiratory infections 1
• Pneumonia specifically: 10 days of treatment 1, 2
• Clinical improvement should be evident within 48-72 hours; if no improvement occurs, reevaluation and further investigation are necessary 1, 2

Critical Dosing Considerations

• Maximum daily dose: Do not exceed 4,000 mg/day of amoxicillin component regardless of weight 1
• For this 35 kg patient, even the high-dose regimen (3,150 mg/day) remains well below the maximum 1
• The American Academy of Pediatrics recommends weight-based dosing for accuracy and safety, with documentation of the child's weight on every prescription 3

Common Pitfalls to Avoid

• Do not use age-based dosing alone—always calculate based on actual body weight in kilograms 3
• Ensure proper formulation selection: The high-dose formulation (600 mg/5 mL or ES-600) provides a 14:1 ratio of amoxicillin to clavulanate, minimizing gastrointestinal side effects while maximizing amoxicillin exposure 4
• Adjust for renal impairment if present: Though not mentioned in this case, failure to adjust doses for renal impairment significantly increases toxicity risk 3
• Complete the full course: Even if symptoms improve before completion, the full prescribed course should be completed 1