What is the recommended dosage of Augmentin (amoxicillin-clavulanate) for an 11-year-old patient weighing 74 pounds with normal renal function and no known allergies to penicillin or amoxicillin?

Augmentin Dosing for an 11-Year-Old Patient Weighing 74 Pounds

For an 11-year-old child weighing 74 pounds (33.6 kg), the recommended dose of Augmentin depends on the indication and severity of infection, but for most respiratory tract infections, the standard dose is 45 mg/kg/day of the amoxicillin component divided into two doses (approximately 750 mg twice daily), while severe infections or areas with high pneumococcal resistance require 90 mg/kg/day divided into two doses (approximately 1,500 mg twice daily). 1, 2

Weight-Based Calculation

• This patient weighs 74 pounds, which converts to 33.6 kg 1
• For standard dosing (45 mg/kg/day): 33.6 kg × 45 mg/kg = 1,512 mg/day total, divided into 756 mg twice daily 1, 2
• For high-dose regimen (90 mg/kg/day): 33.6 kg × 90 mg/kg = 3,024 mg/day total, divided into 1,512 mg twice daily 1, 2

Indication-Specific Dosing Algorithm

For Mild to Moderate Respiratory Infections

• Use the standard dose of 45 mg/kg/day divided into two doses (approximately 750 mg of amoxicillin component twice daily) 1, 3
• This provides adequate coverage for most susceptible pathogens including Streptococcus pneumoniae, Haemophilus influenzae (non-β-lactamase producing), and Streptococcus pyogenes 1

For Severe Infections or High-Risk Situations

• Use the high-dose regimen of 90 mg/kg/day divided into two doses (approximately 1,500 mg of amoxicillin component twice daily) if any of the following risk factors are present: 1, 2
  • Recent antibiotic use within the past 30 days
  • Daycare attendance
  • Geographic area with >10% penicillin-resistant S. pneumoniae
  • Severe infection requiring hospitalization
  • Community-acquired pneumonia
  • Concurrent purulent acute otitis media

For Group A Streptococcal Pharyngitis (Chronic Carriers)

• The dose is 40 mg amoxicillin per kg per day in three doses (maximum 2,000 mg amoxicillin per day) for 10 days 4
• For this patient: 33.6 kg × 40 mg/kg = 1,344 mg/day divided into three doses of approximately 450 mg each 4

Practical Formulation Considerations

• The high-dose formulation provides a 14:1 ratio of amoxicillin to clavulanate, which minimizes gastrointestinal side effects while maintaining efficacy 2, 5
• For this age and weight, tablet formulations are typically more practical than suspension 3
• The maximum single dose should not exceed 2,000 mg regardless of weight 2

Treatment Duration and Monitoring

• Continue treatment for 10 days for most respiratory infections, including pneumonia and acute bacterial sinusitis 1, 2
• Clinical improvement should be evident within 48-72 hours; if no improvement or worsening occurs, reevaluation is necessary 1, 2
• Complete the full course of antibiotics even if symptoms improve before completion 1

Common Pitfalls to Avoid

• Underdosing is a critical error: Using standard doses when high-dose therapy is indicated leads to treatment failure with resistant organisms 2
• Verify the indication: Most upper respiratory tract infections are viral and do not require antibiotics at all 2
• Check for penicillin allergy: Augmentin is contraindicated in patients with serious hypersensitivity reactions to β-lactam antibiotics 3
• Renal function: For patients with normal renal function, no dose adjustment is needed; however, severe renal impairment (GFR <30 mL/min) requires dosage modification 3