What is the recommended dose of amoxicillin (amoxicillin) for pediatric patients with strep throat?

Amoxicillin Dosing for Strep Throat in Pediatric Patients

For Group A Streptococcal pharyngitis (strep throat) in children, the recommended dose of amoxicillin is 50-75 mg/kg/day divided into 2 doses for 10 days, with a maximum of 1000 mg per dose. 1

Standard Dosing Algorithm

The preferred regimen is 50 mg/kg/day divided every 12 hours (approximately 25 mg/kg per dose twice daily), not exceeding 1000 mg per dose, administered for a full 10-day course. 1, 2

• This dosing provides optimal coverage against Streptococcus pyogenes (Group A Streptococcus) while maintaining excellent bacteriologic eradication rates 1
• The twice-daily dosing schedule significantly improves adherence compared to three-times-daily penicillin V regimens 1
• Treatment must continue for the full 10 days to prevent acute rheumatic fever, even if symptoms resolve earlier 1, 3

Weight-Based Calculation Examples

For practical application, calculate the total daily dose and divide by 2:

• Child weighing 20 kg: 50 mg/kg/day = 1000 mg/day total, given as 500 mg twice daily 1
• Child weighing 44.5 kg: 50-75 mg/kg/day = 2225-3337 mg/day, but capped at 1000 mg per dose (2000 mg/day maximum) 1
• Maximum dose: Never exceed 1000 mg per individual dose, regardless of calculated weight-based dosing 1, 2

Critical Treatment Considerations

Children become non-contagious after just 24 hours of appropriate antibiotic therapy, allowing return to school on day 2 if afebrile and clinically improved. 1, 4

• A single dose of amoxicillin (50 mg/kg) results in non-detection of GAS in 91% of children by the following morning 4
• However, the full 10-day course must still be completed to prevent complications, particularly acute rheumatic fever 1, 3

Evidence Supporting This Dosing

The 40-50 mg/kg/day dosing range demonstrates superior efficacy compared to lower-dose penicillin V:

• Amoxicillin 40 mg/kg/day achieved 87.9% clinical cure versus 70.9% with standard-dose penicillin V (p=0.025) 5
• Bacteriologic cure rates were 79.3% with amoxicillin versus 54.5% with penicillin V (p=0.005) 5
• The carrier rate was significantly lower with amoxicillin (10.3%) compared to penicillin V (23.6%) 5

When NOT to Use Standard Amoxicillin

Amoxicillin/clavulanate (Augmentin) should be reserved for treatment failures or chronic GAS carriers, not as first-line therapy for uncomplicated strep throat. 2

• For treatment failures: Use amoxicillin/clavulanate at 40 mg/kg/day of the amoxicillin component (maximum 2000 mg/day) for 10 days 2
• Standard amoxicillin alone remains the preferred first-line agent for initial treatment 2

Penicillin Allergy Alternatives

For children with documented penicillin allergy:

• Non-anaphylactic reactions: Use narrow-spectrum cephalosporins (cephalexin or cefadroxil) for 10 days 1
• Type I hypersensitivity/anaphylaxis: Use clindamycin 10-20 mg/kg/day divided into 3 doses 1
• Macrolides (azithromycin, clarithromycin) have inferior bacteriologic efficacy and should be reserved for true Type I allergies 6, 1

Common Pitfalls to Avoid

Do not use amoxicillin/clavulanate as first-line therapy - this unnecessarily exposes children to broader spectrum coverage and increased adverse effects when standard amoxicillin is highly effective. 2

• Avoid premature discontinuation when symptoms improve - the full 10-day course is essential for preventing rheumatic fever 1, 3
• Do not exceed 1000 mg per dose even in larger children or adolescents 1, 2
• Ensure dosing is based on actual body weight, not age alone 1

Administration Guidance

Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance. 3

• Oral suspension can be mixed with formula, milk, fruit juice, water, or cold drinks if needed, but must be consumed immediately 3
• Reconstituted suspension remains stable for 14 days; refrigeration is preferable but not required 3