What are the recommended antibiotic regimens for bacterial tonsillitis?

Recommended Antibiotic Regimens for Bacterial Tonsillitis

For bacterial tonsillitis caused by Group A Streptococcus (GAS), penicillin V or amoxicillin for 10 days is the first-line treatment, with amoxicillin often preferred due to better taste and once or twice daily dosing options. 1

First-Line Treatment Options

Amoxicillin (Preferred first-line)

• Dosage:
  • Children: 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose)
  • Duration: 10 days

Penicillin V (Traditional first-line)

• Dosage:
  • Children: 30 mg/kg/day divided in 3 doses
  • Adults: Standard dosing
  • Duration: 10 days

Alternative Regimens for Penicillin-Allergic Patients

Azithromycin

• Dosage:
  • Children: 12 mg/kg once daily (maximum 500 mg)
  • Duration: 5 days 1, 2
  • For pharyngitis/tonsillitis specifically, the FDA-approved dosage is 12 mg/kg once daily for 5 days 2

Clindamycin

• Dosage:
  • Children: 20-30 mg/kg/day in 3 divided doses
  • Adults: 300-450 mg orally three times daily
  • Duration: 10 days 1

Treatment Failure Management

If symptoms worsen or don't improve after 48-72 hours of antibiotic therapy, consider the following:

1. Evaluate for:

   • Non-compliance with prescribed regimen
   • Streptococcal carrier with concurrent viral infection
   • New GAS infection
   • True treatment failure (rare) 1

2. Management options:

   • Switch to amoxicillin-clavulanate if failed initial amoxicillin therapy (addresses potential beta-lactamase producing organisms) 1, 3
   • Consider clindamycin for continued treatment failure 1

Clinical Considerations

• Diagnosis: Use Centor Criteria to assess likelihood of GAS pharyngitis (tonsillar exudates, tender anterior cervical lymph nodes, lack of cough, and fever) 1
• Testing: Patients with 3-4 Centor criteria should be tested with rapid antigen detection test (RADT) and/or throat culture 1
• Symptom management: NSAIDs or acetaminophen for pain and fever (avoid aspirin in children due to risk of Reye syndrome) 1

Important Caveats

• Despite GAS being universally susceptible to penicillin, bacteriologic failure occurs in up to 20% of patients treated with penicillin 3
• Beta-lactamase-producing bacteria may "shield" GAS by inactivating penicillin, contributing to treatment failure 3
• Cephalosporins, clindamycin, macrolides, and amoxicillin-clavulanate have shown higher efficacy than penicillin in eradicating infection, especially in patients who failed previous penicillin therapy 3
• While short-course antibiotic therapy (like 3-day azithromycin) may clear streptococci from the throat, complete eradication may require longer treatment courses 4, 5
• In areas with high clarithromycin resistance, 5-day clarithromycin regimens are not recommended for streptococcal tonsillopharyngitis 6

Recurrent Tonsillitis

• Evaluate whether the patient has multiple true GAS infections or is a chronic carrier with viral infections 1
• GAS carriers generally don't require antimicrobial therapy as they are at minimal risk for complications 1
• For patients with recurrent episodes, consider referral for possible tonsillectomy if medical management fails 7