Treatment of Streptococcal Pharyngitis
Penicillin or amoxicillin for 10 days is the first-line treatment for strep throat in non-allergic patients, with amoxicillin offering superior adherence due to once-daily dosing. 1, 2
First-Line Treatment for Non-Allergic Patients
Penicillin and amoxicillin remain the drugs of choice due to their narrow spectrum, proven efficacy, safety profile, and low cost, with no documented penicillin resistance in Group A Streptococcus. 3, 1
Recommended Dosing Options:
Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days - This is the preferred oral regimen as once-daily dosing enhances adherence while maintaining equal efficacy to penicillin 1, 2, 4
Penicillin V: 500 mg twice daily OR 250 mg four times daily for 10 days in adults 1, 2
Benzathine penicillin G intramuscularly: Single dose of 1,200,000 units for patients ≥27 kg or 600,000 units for patients <27 kg - Use this when oral adherence is a concern 1, 2
The once-daily amoxicillin regimen is supported by multiple studies demonstrating equivalent bacteriologic eradication rates compared to multiple-daily penicillin dosing, with improved compliance 5, 6. However, once-daily penicillin V (1000 mg) is NOT recommended, as it shows significantly higher treatment failure rates compared to twice-daily dosing 7.
Treatment for Penicillin-Allergic Patients
The choice of alternative antibiotic depends critically on the type of allergic reaction:
For Non-Immediate (Delayed) Reactions:
- First-generation cephalosporins are preferred - Cephalexin 20 mg/kg twice daily (maximum 500 mg per dose) OR Cefadroxil 30 mg/kg once daily (maximum 1 gram) for 10 days 1, 2
- Cross-reactivity risk is only 0.1% in patients with non-severe, delayed penicillin reactions 1
For Immediate/Anaphylactic Reactions:
Clindamycin is the preferred alternative: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1, 2
Clindamycin resistance remains very low at approximately 1% in the United States 1
Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days - This is the ONLY antibiotic approved for a shorter 5-day course 1, 2
Macrolide resistance is approximately 5-8% in the United States but varies geographically 1
Critical Treatment Duration Requirements
A full 10-day course is mandatory for ALL antibiotics EXCEPT azithromycin to achieve maximal pharyngeal eradication and prevent acute rheumatic fever. 3, 1, 2, 4
This 10-day duration is non-negotiable despite some research suggesting shorter courses may have comparable clinical efficacy 8. The guidelines prioritize prevention of acute rheumatic fever, which requires complete bacterial eradication, not just symptom resolution 3, 1, 2.
Adjunctive Symptomatic Therapy
- Acetaminophen or NSAIDs (such as ibuprofen) should be used for moderate to severe symptoms or high fever 3, 1, 2
- Aspirin must be avoided in children due to Reye syndrome risk 3, 1, 2
- Corticosteroids are NOT recommended 1
Critical Pitfalls to Avoid
Never use cephalosporins in patients with immediate/anaphylactic penicillin reactions - The 10% cross-reactivity risk makes this dangerous 3, 1
Never shorten treatment courses below 10 days for penicillin, amoxicillin, or cephalosporins - This increases treatment failure and rheumatic fever risk despite some research suggesting otherwise 1, 2
Do not use tetracyclines, sulfonamides, trimethoprim-sulfamethoxazole, or older fluoroquinolones - These have high resistance rates or lack efficacy against Group A Streptococcus 3, 9
Do not use broad-spectrum cephalosporins (cefdinir, cefpodoxime) or newer fluoroquinolones routinely - These have unnecessarily broad spectrums and promote antibiotic resistance 3
Follow-Up and Special Considerations
Routine post-treatment throat cultures or rapid antigen tests are NOT recommended for asymptomatic patients who completed therapy 3, 1, 2
Asymptomatic household contacts should NOT be tested or treated routinely - Penicillin prophylaxis has not been shown to reduce subsequent infection rates 3, 1, 9
Treatment can be safely delayed up to 9 days after symptom onset and still prevent acute rheumatic fever 1
Symptoms should improve within 24-48 hours of initiating therapy; if symptoms worsen after 48-72 hours or persist beyond 5 days, reevaluation is warranted 9