Best Antibiotics for Strep Throat
First-Line Treatment
Penicillin is the first-line treatment for group A streptococcal pharyngitis due to its efficacy, safety, narrow spectrum, and low cost. 1 This recommendation is strongly supported by the American Academy of Pediatrics and the Infectious Diseases Society of America.
The recommended dosing regimens for penicillin are:
- Penicillin V: 500 mg 2-3 times daily for adults (250 mg 2-3 times daily for children) for 10 days 1
- The standard 10-day duration is important to prevent acute rheumatic fever 1
Amoxicillin is an acceptable alternative to penicillin V, particularly for young children:
- Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
Clinical Pearl: Twice-daily dosing of penicillin (500 mg twice daily) is as effective as more frequent dosing and may improve compliance compared to four-times-daily dosing 2.
Alternatives for Penicillin-Allergic Patients
For patients with penicillin allergy, the following alternatives are recommended:
Cephalexin: 20 mg/kg twice daily (maximum 500 mg per dose) for 10 days 1
- Note: Only for non-anaphylactic penicillin allergies 3
Clindamycin: 7 mg/kg three times daily (maximum 300 mg per dose) for 10 days 1
Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1
- Caution: There is significant resistance to azithromycin in some parts of the United States 3
- In clinical trials, azithromycin (given for 5 days) has shown superior bacteriologic eradication rates compared to penicillin (95% vs 73% at Day 14) 4
- However, azithromycin is associated with more gastrointestinal adverse effects than amoxicillin (16.8% vs 12.7%) 4
Treatment Considerations
Efficacy Concerns
While penicillin remains the recommended first-line treatment, it's important to note that bacteriologic failure rates with penicillin have increased over time:
- Historical failure rates were 2-10% until the early 1970s
- Current failure rates are reported to be approximately 30% 5
Potential reasons for penicillin failure include:
- Poor compliance with the 10-day regimen
- Reexposure to infected family members
- Copathogenicity with other bacteria
- Eradication of normal protective pharyngeal flora
- Penicillin tolerance 5
Treatment Duration
The standard duration for penicillin and amoxicillin treatment is 10 days to prevent complications such as acute rheumatic fever 1.
Follow-up and Recurrence
- Routine follow-up testing is not recommended for asymptomatic patients after completing treatment 1
- For recurrence shortly after treatment completion, consider retreatment with the same antibiotic or intramuscular benzathine penicillin G 1
- Patients are considered non-contagious after 24 hours of antibiotic therapy 1
Symptom Management
In addition to antibiotics, symptom relief is important:
- Ibuprofen (preferred): 400mg every 6-8 hours as needed
- Acetaminophen: 500-1000mg every 4-6 hours as needed 1
When to Consider Alternative Approaches
- For patients with multiple recurrences (7 episodes in 1 year, 5 episodes in each of 2 years, or 3 episodes in each of 3 years), tonsillectomy may be considered 3
- Patients with worsening symptoms after antibiotic initiation or symptoms lasting 5 days after starting treatment should be reevaluated 3
Pitfalls to Avoid
- Overtreatment: Only 10% of adults with sore throat have group A streptococcal pharyngitis, yet 60% or more receive antibiotics 3
- Inadequate duration: Shortening the standard 10-day course may increase risk of complications
- Inappropriate antibiotic selection: Using broad-spectrum antibiotics when narrow-spectrum would suffice
- Failing to consider resistance patterns: Particularly important when prescribing macrolides like azithromycin 3