First-Line Treatment for Strep Throat
Penicillin V or amoxicillin remains the definitive first-line treatment for strep throat due to proven efficacy, safety, narrow spectrum, low cost, and the complete absence of penicillin resistance in Group A Streptococcus over five decades. 1, 2
Primary Treatment Regimen
For non-penicillin-allergic patients, use:
- Children: Penicillin V 250 mg orally 2-3 times daily for 10 days 1
- Adolescents and adults: Penicillin V 250 mg four times daily OR 500 mg twice daily for 10 days 1
- Alternative for children: Amoxicillin 50 mg/kg once daily (maximum 1000 mg) for 10 days, which offers better palatability and once-daily dosing to improve adherence 1, 2
The 10-day duration is critical for maximal pharyngeal eradication of Group A Streptococcus and prevention of rheumatic fever. 1, 2 Penicillin has never developed resistance anywhere globally, making it uniquely reliable. 2, 3
When oral compliance is questionable, particularly in underserved populations where follow-up is unreliable, use intramuscular benzathine penicillin G: 600,000 units for patients <60 lbs (27 kg) or 1,200,000 units for patients ≥60 lbs as a single dose. 1, 2
Treatment for Penicillin-Allergic Patients
The choice depends on the type of allergic reaction:
Non-Immediate/Non-Anaphylactic Allergy
Immediate Hypersensitivity/Anaphylactic Allergy
Avoid cephalosporins due to 10% cross-reactivity risk. 4 Use instead:
- Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days (strong, moderate evidence) 1
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days (strong, moderate evidence) 1
- Clarithromycin: 7.5 mg/kg twice daily (maximum 250 mg per dose) for 10 days (strong, moderate evidence) 1
Critical Considerations and Pitfalls
Macrolide resistance is a significant concern. Geographic resistance rates for azithromycin and clarithromycin range from 5-8% in the United States but vary temporally and geographically. 1, 4 The FDA label for azithromycin explicitly states that susceptibility testing should be performed and that data establishing efficacy in preventing rheumatic fever are not available. 5 Despite this, azithromycin remains guideline-recommended for penicillin-allergic patients when macrolides are appropriate. 1
Clindamycin has only 1% resistance among U.S. Group A Streptococcus isolates and demonstrates high efficacy even in chronic carriers, making it an excellent choice for severe penicillin allergy. 4
Do not use broad-spectrum antibiotics like amoxicillin-clavulanate (Augmentin) as first-line therapy. This increases costs, promotes antimicrobial resistance, and causes more gastrointestinal side effects without providing additional clinical benefit. 3 Reserve Augmentin only for chronic GAS carriers at 40 mg amoxicillin/kg/day in three divided doses for 10 days. 1, 3
Complete the full 10-day course for all antibiotics except azithromycin (5 days due to prolonged tissue half-life). 1, 4 Shorter courses lead to treatment failure and potential complications including rheumatic fever. 2
When to Treat
Only treat patients with confirmed Group A Streptococcus via throat culture or rapid antigen detection testing. 2 For patients with 0-2 Centor criteria (fever, tonsillar exudates, tender anterior cervical lymphadenopathy, absence of cough), antibiotics should not be used. 1 For those with 3-4 Centor criteria, testing is warranted, and treatment provides modest symptom reduction of 1-2 days. 1, 2
Adjunctive Symptomatic Management
- Acetaminophen or NSAIDs (like ibuprofen) for pain and fever relief 2, 4
- Avoid aspirin in children due to Reye syndrome risk 2, 4
- Do not use corticosteroids routinely 2, 4
Post-treatment testing is not routinely recommended for asymptomatic patients who completed therapy, as chronic carriage is common and these individuals are at low risk for complications or transmission. 1, 2