Treatment of Streptococcal Pharyngitis (Strep Throat)
Penicillin or amoxicillin is the first-line treatment for streptococcal pharyngitis due to their proven efficacy, safety, narrow spectrum of activity, and low cost. 1, 2
First-Line Treatment Options
For patients without penicillin allergy:
- Oral penicillin V for 10 days: 250 mg 2-3 times daily for children; 250 mg 4 times daily or 500 mg twice daily for adolescents and adults 1, 3
- Oral amoxicillin for 10 days: 50 mg/kg once daily (maximum 1,000 mg) or 25 mg/kg twice daily (maximum 500 mg) 1
- Intramuscular benzathine penicillin G (single dose) for patients unlikely to complete a full 10-day oral course: 600,000 units for patients <60 lb (27 kg) and 1,200,000 units for patients ≥60 lb 1, 2
Treatment for Penicillin-Allergic Patients
For patients with penicillin allergy:
- Non-immediate (non-anaphylactic) penicillin allergy: First-generation cephalosporins such as cephalexin (20 mg/kg twice daily) or cefadroxil (30 mg/kg once daily) for 10 days 4
- Immediate/severe penicillin allergy: Clindamycin (7 mg/kg three times daily for 10 days, maximum 300 mg per dose) 4
- Alternative for severe penicillin allergy: Macrolides such as erythromycin (20-40 mg/kg/day divided 2-3 times daily for 10 days) or azithromycin (12 mg/kg once daily for 5 days, maximum 500 mg) 4, 5
Duration of Therapy
- A full 10-day course of antibiotics is recommended for most agents to ensure complete eradication of the organism and prevent rheumatic fever 1, 2, 6
- Azithromycin is the exception, requiring only a 5-day course due to its prolonged tissue half-life 4, 5
- Shortened courses (5-7 days) have shown similar effectiveness in some studies but are not universally recommended by guidelines 7
Important Considerations
- Patients are typically no longer contagious after 24 hours of appropriate antibiotic therapy 2
- Clinical improvement usually occurs within 24-48 hours of starting antibiotics 2
- Routine post-treatment throat cultures are not recommended for asymptomatic patients who have completed therapy 2
- Penicillin failure rates have increased over time, possibly due to poor compliance with the 10-day regimen 8
Treatment of Recurrent Streptococcal Pharyngitis
- Treat recurrences with the same antimicrobial agent used initially 2
- Consider intramuscular benzathine penicillin G if compliance with oral therapy is questionable 2
- For multiple recurrences, consider alternative antibiotics such as clindamycin or amoxicillin/clavulanate due to their higher rates of pharyngeal eradication 2, 4
Adjunctive Therapy
- Acetaminophen or NSAIDs for moderate to severe symptoms or high fever 1
- Avoid aspirin in children due to the risk of Reye syndrome 1
- Corticosteroids are not recommended as adjunctive therapy 4
Pitfalls to Avoid
- Do not treat likely viral pharyngitis (with cough, rhinorrhea, hoarseness, oral ulcers) with antibiotics 1
- Be aware of local macrolide resistance patterns when prescribing these agents 4
- Ensure patients complete the full course of antibiotics to prevent treatment failure and complications 6
- For penicillin treatment, non-compliance is a major cause of treatment failure 8