What is the drug of choice for bacterial pharyngitis?

Drug of Choice for Bacterial Pharyngitis

Penicillin or amoxicillin is the recommended drug of choice for bacterial pharyngitis due to Group A Streptococcus (GAS) based on their proven efficacy, safety, narrow spectrum of activity, and low cost. 1

First-Line Treatment Options

For patients without penicillin allergy:

• Oral Penicillin V:

  • Adults: 250 mg 2-3 times daily for 10 days
  • Children: Weight-based dosing for 10 days

• Oral Amoxicillin (alternative with equivalent efficacy):

  • 50 mg/kg once daily (maximum 1000 mg) for 10 days 1, 2
  • Advantage: Once-daily dosing may improve adherence
  • Particularly useful for young children due to better taste acceptance

• Intramuscular Benzathine Penicillin G (single dose):

  • Preferred for patients unlikely to complete a full oral course
  • <60 lb (27 kg): 600,000 units IM

  • 60 lb (27 kg): 1,200,000 units IM 2

Alternative Treatments for Penicillin-Allergic Patients

For patients with penicillin allergy:

1. First-generation cephalosporins (if not anaphylactically sensitive):

   • Cephalexin: 20 mg/kg twice daily (max 500 mg per dose) for 10 days
   • Cefadroxil: 30 mg/kg once daily (max 1 g) for 10 days 1, 2

2. Clindamycin: 7 mg/kg per dose three times daily for 10 days 1, 2

   • Excellent coverage against GAS with minimal resistance reported in the US

3. Clarithromycin: 7.5 mg/kg twice daily (max 250 mg per dose) for 10 days 2

4. Azithromycin: 12 mg/kg once daily (max 500 mg) for 5 days 1, 2, 3

   • Note: FDA-approved for shorter course (5 days)
   • Caution: Macrolide resistance has been reported in up to 5% of GAS in the US

Treatment Considerations

Efficacy and Resistance

• Penicillin-resistant GAS has never been documented 1
• The 10-day duration for most antibiotics is necessary to achieve maximal pharyngeal eradication of GAS 1
• While some newer antibiotics (cefdinir, cefpodoxime, azithromycin) are FDA-approved for shorter courses, the IDSA does not endorse these shorter regimens due to broader spectrum and higher cost 1

Medications to Avoid

• Tetracyclines: High prevalence of resistant strains
• Sulfonamides and trimethoprim-sulfamethoxazole: Do not eradicate GAS
• Older fluoroquinolones (e.g., ciprofloxacin): Limited activity against GAS
• Newer fluoroquinolones: Unnecessarily broad spectrum and expensive 1

Adjunctive Therapy

• Acetaminophen or ibuprofen for pain and fever control
• Avoid aspirin in children (risk of Reye syndrome) 2

Follow-up Recommendations

• Patients are considered non-contagious after 24 hours of antibiotic therapy 2
• Clinical response typically occurs within 24-48 hours of starting treatment 1, 2
• Follow-up throat cultures or rapid antigen detection tests are not routinely recommended 1
• Complete the full antibiotic course even if symptoms resolve quickly 2

Important Caveats

• GAS pharyngitis is usually self-limited, but treatment reduces symptom duration and prevents complications like acute rheumatic fever 1
• If symptoms persist after 5 days of appropriate treatment, consider:
  • Non-compliance with prescribed regimen
  • Penicillin treatment failure
  • New GAS infection
  • Viral pharyngitis in a GAS carrier 2