What is the drug of choice and appropriate dosage for acute streptococcal pharyngitis in a healthy 10‑year‑old child weighing 58 lb (≈26 kg)?

Drug of Choice and Dosing for Strep Throat in a 10-Year-Old

For a 10-year-old child weighing 58 lb (26 kg) with streptococcal pharyngitis, prescribe amoxicillin 1,000 mg once daily (or 500 mg twice daily) for a full 10 days. 1, 2

Recommended First-Line Treatment

Amoxicillin is the drug of choice for Group A Streptococcal pharyngitis in children without penicillin allergy, with strong, high-quality evidence supporting its use. 1, 2

Specific Dosing for This Patient

For a 26 kg child, calculate the dose using the weight-based regimen:

• Once-daily dosing (preferred): 50 mg/kg once daily = 1,300 mg, but maximum dose is 1,000 mg once daily for 10 days 1, 2
• Twice-daily alternative: 25 mg/kg per dose = 650 mg per dose, but maximum is 500 mg per dose twice daily for 10 days 1, 2

The once-daily regimen is preferred because it enhances adherence while maintaining equivalent efficacy to traditional multi-dose therapy. 2

Critical Treatment Requirements

A full 10-day course is mandatory regardless of symptom resolution to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever. 1, 2 Even though symptoms typically resolve within 3-4 days, shortening the course by even a few days results in appreciable increases in treatment failure rates and risk of acute rheumatic fever. 2

Why Amoxicillin Over Penicillin V

Amoxicillin is preferred over penicillin V in younger children due to:

• Better palatability and availability as suspension 3
• Identical efficacy for Group A Streptococcal pharyngitis 3
• Narrow spectrum of activity with few adverse effects 3
• Once-daily dosing option that improves adherence 2, 3

Alternatives for Penicillin Allergy

If this child had a penicillin allergy, the choice depends on the type of reaction:

For Non-Immediate (Delayed) Reactions

First-generation cephalosporins are preferred with only 0.1% cross-reactivity risk in non-severe delayed reactions: 2, 4

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg/dose) for 10 days 1, 2
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 1, 2

For Immediate/Anaphylactic Reactions

Clindamycin is the preferred choice with only 1% resistance in the United States: 2, 4

• Clindamycin: 7 mg/kg per dose three times daily (maximum 300 mg/dose) for 10 days 1, 2

Azithromycin is an acceptable alternative but not preferred due to 5-8% macrolide resistance: 2, 4

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days only 1, 2

Common Pitfalls to Avoid

• Never shorten the treatment course below 10 days (except azithromycin's 5-day regimen) as this dramatically increases treatment failure and rheumatic fever risk 2
• Do not use trimethoprim-sulfamethoxazole (Bactrim) as it fails to eradicate Group A Streptococcus in 20-25% of cases 4
• Avoid tetracyclines, sulfonamides, or older fluoroquinolones as they are ineffective for Group A Streptococcus eradication 2
• Do not prescribe azithromycin as first-line when amoxicillin can be used, as this unnecessarily broadens the antibiotic spectrum and contributes to resistance 2
• Avoid aspirin in children due to the risk of Reye syndrome 2

Adjunctive Symptomatic Care

• Acetaminophen or ibuprofen should be considered for moderate to severe symptoms or high fever 2
• Corticosteroids are not recommended as adjunctive therapy 2

Expected Outcomes

• The child will be non-contagious after 24 hours of antibiotic therapy 3
• Symptoms should improve within 48-72 hours; if no improvement occurs, consider non-compliance or alternative diagnosis 2
• Early treatment reduces symptom duration to less than 24 hours in most cases and permits earlier return to school 5