What is the appropriate dose of Augmentin (amoxicillin/clavulanate) 500 mg/125 mg for a 12‑year‑old child?

Augmentin 500mg/125mg Dosing for a 12-Year-Old

For a 12-year-old child, the appropriate dose of Augmentin 500mg/125mg is one tablet every 12 hours for standard infections, or one tablet every 8 hours for more severe respiratory tract infections. 1

Weight-Based Dosing Threshold

• Pediatric patients weighing 40 kg or more should be dosed according to adult recommendations, which means they transition from weight-based to fixed-dose regimens. 1
• Most 12-year-old children weigh ≥40 kg, making them eligible for adult dosing schedules. 2

Standard Adult Dosing Regimen (for children ≥40 kg)

• The usual dose is one 500mg/125mg tablet every 12 hours for most infections. 1
• For more severe infections and respiratory tract infections, the dose should be one 875mg/125mg tablet every 12 hours OR one 500mg/125mg tablet every 8 hours. 1
• The maximum daily dose of amoxicillin should not exceed 4,000 mg regardless of weight. 3, 2

Weight-Based Dosing (for children <40 kg)

If the 12-year-old weighs less than 40 kg, use weight-based dosing instead:

High-Dose Regimen (for severe infections or resistant pathogens)

• 90 mg/kg/day of the amoxicillin component divided into 2 doses (maximum 4 g/day) is recommended for:
  • Community-acquired pneumonia 3, 2
  • Areas with high pneumococcal resistance (>10%) 2
  • Recent antibiotic use within 30 days 2
  • Severe infections 3

Standard-Dose Regimen (for less severe infections)

• 45 mg/kg/day of the amoxicillin component divided into 2 doses for uncomplicated respiratory tract infections in children without risk factors. 3, 2

Critical Dosing Considerations

• The 500mg/125mg tablet formulation is NOT interchangeable with other Augmentin formulations because the clavulanate content differs. 1
• Two 250mg/125mg tablets should NOT be substituted for one 500mg/125mg tablet, as both contain the same amount of clavulanate (125mg), making the substitution inappropriate. 1
• Augmentin should be taken at the start of a meal to enhance clavulanate absorption and minimize gastrointestinal intolerance. 1

Indication-Specific Guidance

Respiratory Tract Infections

• For community-acquired pneumonia in a 12-year-old, use the high-dose regimen of 90 mg/kg/day in 2 doses if the child weighs <40 kg, or one 875mg/125mg tablet every 12 hours if ≥40 kg. 3, 2
• Treatment duration is typically 10 days for pneumonia. 2, 4

Acute Otitis Media or Sinusitis

• High-dose therapy (90 mg/kg/day in 2 doses) is indicated for children with risk factors including age <2 years, daycare attendance, or recent antibiotic exposure. 2, 4
• For a 12-year-old without these risk factors, standard adult dosing (500mg/125mg every 12 hours) is appropriate. 1

Monitoring and Follow-Up

• Clinical improvement should be evident within 48-72 hours of starting therapy. 2, 4
• If no improvement or worsening occurs after 48-72 hours, reevaluation and consideration of alternative antibiotics or further investigation is necessary. 2, 4
• Complete the full prescribed course even if symptoms improve before completion. 2

Common Pitfalls to Avoid

• Do not use subtherapeutic doses, as they fail to achieve adequate tissue concentrations and promote antimicrobial resistance. 4
• Verify the patient's weight before deciding between adult fixed-dose and pediatric weight-based regimens; the 40 kg threshold is critical. 2, 1
• Do not prescribe based solely on age—a small 12-year-old weighing <40 kg requires weight-based dosing, while a larger child ≥40 kg uses adult dosing. 2, 1