First-Line Treatment for Strep Throat
Penicillin V or amoxicillin for 10 days is the first-line treatment for strep throat in non-allergic patients, based on proven efficacy, narrow spectrum, safety, and low cost. 1
Primary Treatment Regimen
For Non-Penicillin Allergic Patients
Oral Penicillin V (Drug of Choice):
- Children: 250 mg twice or three times daily for 10 days 1
- Adolescents and adults: 250 mg three to four times daily OR 500 mg twice daily for 10 days 1
Amoxicillin (Equally Effective Alternative):
- Children: 50 mg/kg once daily (maximum 1000 mg) for 10 days 1, 2
- Amoxicillin is often preferred in young children due to better palatability of the suspension compared to penicillin V 1
- Once-daily dosing may enhance adherence while maintaining equal efficacy to penicillin V 1
Intramuscular Benzathine Penicillin G:
- 1.2 million units as a single dose 1
- Preferred for patients unlikely to complete a full 10-day oral course (e.g., poor compliance anticipated, lack of follow-up access) 1
For Penicillin-Allergic Patients
Non-Immediate (Non-Anaphylactic) Allergy:
- First-generation cephalosporins for 10 days 1, 2
- Cephalexin is an appropriate option 3
- Cefpodoxime 100 mg twice daily for 10 days in adults and adolescents 2
Immediate-Type Hypersensitivity (Anaphylaxis):
- Erythromycin estolate: 20-40 mg/kg/day (maximum 1 g/day) divided twice or three times daily for 10 days 1
- Erythromycin ethyl succinate: 40 mg/kg/day (maximum 1 g/day) divided twice or three times daily for 10 days 1
- Clarithromycin for 10 days 1
- Azithromycin for 5 days (maximum 500 mg once daily) 1, 4
- Clindamycin for 10 days 1
Critical Clinical Considerations
Duration of Therapy
- The full 10-day course is essential to achieve maximal pharyngeal eradication of group A streptococci and prevent rheumatic fever 1
- While some newer agents (azithromycin, certain cephalosporins) have been studied in shorter courses (≤5 days), the IDSA guidelines emphasize that definitive comprehensive data are lacking to endorse these shorter regimens 1
- The 2012 guideline notes that 5-day azithromycin is acceptable for penicillin-allergic patients, but this represents an exception rather than the standard 1
Why Penicillin Remains First-Line
- No documented penicillin resistance: Group A streptococci have never developed resistance to penicillin anywhere in the world 1
- Narrow spectrum: Minimizes disruption of normal flora and reduces selection pressure for resistant organisms 1
- Proven efficacy: Decades of data confirm effectiveness in preventing rheumatic fever 1
- Low cost: Significantly less expensive than broader-spectrum alternatives 1
- Minimal adverse effects: Well-tolerated with infrequent side effects 1
Common Pitfalls to Avoid
Do not use broader-spectrum agents as first-line therapy when penicillin can be used:
- Cephalosporins and macrolides are more expensive and have broader spectra, potentially selecting for antibiotic-resistant flora 2
- Reserve these agents for documented penicillin allergy or treatment failure 1, 2
Do not use cephalosporins in patients with immediate-type penicillin hypersensitivity:
- Cross-reactivity occurs in up to 10% of penicillin-allergic patients 2
- Use macrolides or clindamycin instead 1
Do not prescribe shorter courses without clear indication:
- While research suggests some agents may be effective in 5 days, the standard remains 10 days for most antibiotics to ensure bacterial eradication 1
- Azithromycin 5-day course is the exception for penicillin-allergic patients 1, 4
Ensure compliance:
- If adherence to a 10-day oral regimen is questionable, use intramuscular benzathine penicillin G instead 1
- This is particularly important in populations with limited healthcare access or where rheumatic fever remains prevalent 1
Do not routinely test or treat asymptomatic household contacts:
- Testing and treating asymptomatic contacts is not recommended unless special circumstances exist (e.g., outbreak settings, high risk of complications) 1