What oral antibiotic covers Group A beta-hemolytic streptococcal (GABHS) infections?

Oral Antibiotics for Group A Beta-Hemolytic Streptococcal Infections

Penicillin V (250-500 mg twice daily for 10 days) or amoxicillin (500-1000 mg once daily for 10 days) are the first-line oral antibiotics for Group A streptococcal infections in non-allergic patients. 1, 2

First-Line Treatment for Non-Allergic Patients

Penicillin V remains the drug of choice due to proven efficacy, safety, narrow spectrum, low cost, and zero documented resistance worldwide. 1, 2

• Dosing for adults: 250 mg four times daily OR 500 mg twice daily for 10 days 1, 2
• Dosing for children: 250 mg twice or three times daily for 10 days 2

Amoxicillin is equally effective and often preferred in young children due to better palatability of the suspension. 2, 3

• Dosing for adults: 500 mg every 12 hours or 250 mg every 8 hours for 10 days 3
• Dosing for children: 50 mg/kg once daily (maximum 1000 mg) OR 25 mg/kg twice daily (maximum 500 mg) for 10 days 2
• Amoxicillin once-daily dosing is non-inferior to twice-daily penicillin V for GABHS eradication 4

Critical: A full 10-day course is mandatory to achieve maximal pharyngeal eradication and prevent acute rheumatic fever. 1, 2

Treatment for Penicillin-Allergic Patients

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

First-generation cephalosporins are the preferred alternatives with only 0.1% cross-reactivity risk in non-severe delayed reactions. 5, 2

• Cephalexin: 500 mg every 12 hours for adults; 20 mg/kg/dose twice daily (maximum 500 mg/dose) for children, for 10 days 5, 2
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 5, 2

Immediate/Anaphylactic Penicillin Allergy

All beta-lactams must be avoided due to up to 10% cross-reactivity risk. 5, 1

Clindamycin is the preferred choice with approximately 1% resistance rate in the United States and high efficacy even in chronic carriers. 5, 6

• Dosing: 300 mg three times daily for adults; 7 mg/kg/dose three times daily (maximum 300 mg/dose) for children, for 10 days 5, 1, 6
• Clindamycin should be reserved for penicillin-allergic patients per FDA labeling 6

Macrolides are acceptable alternatives but have 5-8% resistance rates in the United States. 5, 1

• Azithromycin: 500 mg on day 1, then 250 mg once daily for 4 days (adults); 12 mg/kg once daily (maximum 500 mg) for 5 days (children) 5, 1
  • Only antibiotic requiring just 5 days due to prolonged tissue half-life 5, 1
• Clarithromycin: 250 mg twice daily for adults; 7.5 mg/kg/dose twice daily (maximum 250 mg/dose) for children, for 10 days 5, 2

Critical Pitfalls to Avoid

• Never shorten the course below 10 days (except azithromycin's 5-day regimen) as this dramatically increases treatment failure and rheumatic fever risk 5, 2
• Never use sulfonamides or tetracyclines due to high resistance rates and frequent treatment failures 1, 2
• Never use cephalosporins in patients with anaphylaxis, angioedema, or immediate urticaria to penicillin due to 10% cross-reactivity risk 5, 1
• Be aware of local macrolide resistance patterns before prescribing azithromycin or clarithromycin, as resistance varies geographically 5, 1

When to Use Intramuscular Therapy

Benzathine penicillin G is preferred when oral compliance is uncertain: 600,000 units for patients <27 kg; 1,200,000 units for patients ≥27 kg as a single intramuscular dose. 1, 2