What is the proper dosing of amoxicillin (amoxicillin) for pediatric patients?

Amoxicillin Dosing Guidelines for Pediatric Patients

The recommended dosage of amoxicillin for pediatric patients varies by indication, with standard dosing of 45 mg/kg/day in 2 divided doses for mild to moderate infections and 90 mg/kg/day in 2 divided doses for severe infections or in areas with high pneumococcal resistance. 1

Dosing by Age and Weight

Infants and Children ≥3 Months (≥12 weeks) and <40 kg

• For mild/moderate ear, nose, throat, skin, and genitourinary infections: 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours 2
• For severe ear, nose, throat, skin, and genitourinary infections: 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours 2
• For lower respiratory tract infections (mild/moderate or severe): 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours 2
• For community-acquired pneumonia: 90 mg/kg/day in 2 doses (preferred) or 45 mg/kg/day in 3 doses 3, 1
• For Group A Streptococcal infections: 50-75 mg/kg/day in 2 doses 3, 1

Infants <12 weeks (3 months)

• Due to incompletely developed renal function, the recommended upper dose is 30 mg/kg/day divided every 12 hours 2

Dosing by Indication

Respiratory Tract Infections

• For community-acquired pneumonia with minimal penicillin resistance: 45 mg/kg/day in 2 or 3 divided doses 3, 1
• For areas with high pneumococcal resistance: 90 mg/kg/day in 2 divided doses 3, 1
• For H. influenzae infections (β-lactamase negative): 75-100 mg/kg/day in 3 doses 3

Streptococcal Infections

• For Group A Streptococcal infections: 50-75 mg/kg/day in 2 doses 3, 1
• Treatment should continue for at least 10 days for any infection caused by Streptococcus pyogenes to prevent acute rheumatic fever 2

Administration Considerations

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 2
• Twice-daily dosing has similar efficacy to three-times-daily dosing and may improve adherence 4
• Treatment should continue for a minimum of 48 to 72 hours beyond symptom resolution 2

Dosage Adjustment for Renal Impairment

• Pediatric patients with impaired renal function generally don't require dose reduction unless impairment is severe 2
• For severe renal impairment (GFR 10-30 mL/min): 500 mg or 250 mg every 12 hours, depending on infection severity 2
• For GFR <10 mL/min: 500 mg or 250 mg every 24 hours, depending on infection severity 2

Maximum Dosing Considerations

• The maximum daily dose for children should not exceed 4000 mg (4 g) per day 1
• For children approaching adult weight, some clinicians cap the dose at the standard adult dose of 1500 mg/day, though this practice varies 5

Monitoring and Follow-up

• Clinical improvement should be observed within 48-72 hours of starting appropriate therapy 1
• If no improvement is seen within this timeframe, reevaluation is necessary 1
• Complete the full course of antibiotics as prescribed, even if symptoms improve before completion 1

Common Pitfalls and Considerations

• Underdosing is common in heavier children, with studies showing physicians often prescribe lower-than-recommended doses for children in higher weight categories 5
• For acute otitis media, especially with viral co-infection, standard dosing (40 mg/kg/day) may be inadequate; higher dosing (75-90 mg/kg/day) is recommended 6
• Weight-based dosing is preferred over age-based dosing for accuracy 7
• Prescriptions should include daily dose, number of divided doses, duration of therapy, indication, and child's weight to ensure safe and effective treatment 7