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

Amoxicillin Dosing for Pediatric Streptococcal Pharyngitis

The recommended dose of amoxicillin for pediatric patients with streptococcal pharyngitis is 50 mg/kg once daily (maximum 1000 mg) or alternatively 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days. 1

Dosing Regimen Details

First-line Treatment Options:

• Once-daily dosing: 50 mg/kg once daily (maximum 1000 mg) 1
• Twice-daily dosing: 25 mg/kg twice daily (maximum 500 mg per dose) 1
• Duration: 10 days (mandatory to prevent acute rheumatic fever) 1, 2

This dosing recommendation is supported by the Infectious Diseases Society of America (IDSA) 2012 clinical practice guidelines for the management of Group A Streptococcal pharyngitis, which provides strong evidence with high quality for this regimen 1.

Administration Considerations:

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 2
• The suspension should be shaken well before using 2

Alternative Options for Penicillin-Allergic Patients

For patients with penicillin allergy, alternative options include:

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1 Note: Avoid in patients with immediate hypersensitivity to penicillin
• Clindamycin: 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days 1
• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1 Note: Group A streptococcal resistance to macrolides is well-known and varies geographically

Clinical Evidence Supporting Once-Daily Dosing

Recent research supports the efficacy of once-daily amoxicillin dosing:

• A study using real-time PCR to measure bacterial load found no statistical difference in Group A Streptococcus (GAS) eradication between once-daily, twice-daily, and three-times-daily amoxicillin regimens 3
• Once-daily dosing may improve compliance compared to multiple daily doses, which is particularly important since non-compliance is a major cause of treatment failure 4

Important Clinical Considerations

Treatment Duration

• A full 10-day course is mandatory for streptococcal pharyngitis to prevent acute rheumatic fever 2
• While shorter courses (3-6 days) of certain antibiotics have been studied 5, the standard recommendation remains 10 days of amoxicillin therapy for complete eradication of GAS and prevention of complications 1

Common Pitfalls to Avoid

1. Inadequate dosing: Underdosing amoxicillin can lead to treatment failure
2. Insufficient duration: Stopping antibiotics before completing the full 10-day course increases risk of rheumatic fever
3. Inappropriate antibiotic selection: Using macrolides as first-line therapy when not indicated by penicillin allergy (resistance concerns)
4. Failure to reassess: Not following up after 48-72 hours if symptoms persist

Return to School Considerations

• Research indicates that children treated with a full dose of amoxicillin (50 mg/kg) may be non-infectious as early as 12-24 hours after initiation of therapy if they are afebrile and clinically improved 6

Treatment Algorithm

1. Confirm diagnosis of GAS pharyngitis through rapid antigen detection test or throat culture
2. Assess for penicillin allergy
3. If no penicillin allergy: Prescribe amoxicillin 50 mg/kg once daily (max 1000 mg) for 10 days
4. If penicillin allergic: Select appropriate alternative based on allergy type
5. Follow-up if symptoms persist beyond 48-72 hours of treatment initiation

Amoxicillin's once-daily dosing offers the advantages of improved compliance while maintaining excellent efficacy against GAS, making it an optimal choice for pediatric streptococcal pharyngitis.