Treatment for Strep Throat
Penicillin or amoxicillin for 10 days is the definitive first-line treatment for strep throat, with no documented resistance and proven efficacy in preventing rheumatic fever. 1
First-Line Antibiotic Therapy
Penicillin V or amoxicillin remains the gold standard due to proven efficacy, narrow spectrum of activity, safety profile, and low cost. 1 Group A streptococcus has never developed resistance to penicillin over five decades of use. 1
Recommended Dosing Regimens:
Adults:
- Penicillin V: 500 mg orally twice daily for 10 days 1, 2
- Amoxicillin: 500 mg twice daily for 10 days 1, 3
Children ≥40 kg:
- Same as adult dosing 3
Children <40 kg:
- Amoxicillin: 25 mg/kg/day divided twice daily (or 50 mg/kg once daily, maximum 1000 mg) for 10 days 1, 3
- Penicillin V: 250 mg twice or three times daily for 10 days 1, 2
Intramuscular option when adherence is questionable:
- Benzathine penicillin G: 600,000 units for children <27 kg; 1,200,000 units for ≥27 kg (single dose) 1
Alternatives for Penicillin-Allergic Patients
Non-Immediate/Non-Anaphylactic Penicillin Allergy:
First-generation cephalosporins are the preferred alternatives with strong, high-quality evidence and only 0.1% cross-reactivity risk in non-severe delayed reactions. 1, 4
- Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days 1
- Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 1
Immediate/Anaphylactic Penicillin Allergy:
Clindamycin is the preferred choice with approximately 1% resistance rate in the United States and demonstrated high efficacy even in chronic carriers. 1, 4
Macrolide alternatives (less preferred due to resistance):
- Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
- Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1
Critical Treatment Duration Requirements
A full 10-day course is mandatory for all antibiotics except azithromycin to achieve maximal pharyngeal eradication of Group A streptococcus and prevent acute rheumatic fever. 1, 2 Shortening the course by even a few days dramatically increases treatment failure rates and rheumatic fever risk. 1, 4
Azithromycin requires only 5 days due to its prolonged tissue half-life and unique pharmacokinetics. 1, 4
Important Resistance Considerations
- Macrolide resistance: Approximately 5-8% in the United States, varying geographically 1, 4, 5
- Clindamycin resistance: Only ~1% in the United States 1, 4
- Penicillin resistance: Never documented anywhere in the world 1
Adjunctive Symptomatic Treatment
Acetaminophen or NSAIDs can be considered for moderate to severe symptoms or high fever. 1, 4
Aspirin must be avoided in children due to Reye syndrome risk. 1, 4
Corticosteroids are not recommended as adjunctive therapy. 1, 4
Common Pitfalls to Avoid
Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to up to 10% cross-reactivity risk with all beta-lactam antibiotics. 1, 4
Do not prescribe shorter courses than recommended (except azithromycin's 5-day regimen), as this increases treatment failure and rheumatic fever risk. 1, 2
Do not use trimethoprim-sulfamethoxazole or tetracyclines for strep throat—they do not eradicate Group A streptococcus and have high resistance rates. 1
Check local macrolide resistance patterns before prescribing azithromycin or clarithromycin, as resistance varies geographically and can lead to treatment failure. 4, 2
Do not routinely perform follow-up throat cultures in asymptomatic patients who have completed therapy. 1, 2
When to Reevaluate
Patients with worsening symptoms after appropriate antibiotic initiation or symptoms lasting 5 days after starting treatment should be reevaluated for complications or alternative diagnoses. 5