What are the first-line antibiotics for acute tonsillitis?

First-Line Antibiotics for Acute Tonsillitis

For patients with acute tonsillitis, penicillin V is the first-line antibiotic treatment of choice, with amoxicillin as an acceptable alternative in younger children due to taste considerations. 1

Diagnosis Considerations

Before prescribing antibiotics, it's important to determine if the tonsillitis is likely bacterial (specifically Group A Streptococcus) rather than viral:

• Use Centor criteria to assess likelihood of bacterial infection:

  • Fever >38°C
  • Absence of cough
  • Tender anterior cervical lymphadenopathy
  • Tonsillar exudate
  • Age considerations (higher score for ages 3-14, lower for older patients)

• Throat culture or rapid antigen detection test (RADT) should be performed when bacterial etiology is suspected

First-Line Treatment Options

For Patients Without Penicillin Allergy:

1. Penicillin V (oral) 1

   • Children: 250 mg 2-3 times daily for 10 days
   • Adolescents/adults: 250 mg 4 times daily or 500 mg twice daily for 10 days
   • Strong recommendation, high-quality evidence

2. Amoxicillin (oral) 1

   • 50 mg/kg once daily (max 1000 mg) for 10 days
   • Alternative: 25 mg/kg twice daily (max 500 mg per dose) for 10 days
   • Often preferred in younger children due to better taste and availability as syrup
   • Strong recommendation, high-quality evidence

3. Benzathine penicillin G (intramuscular) 1

   • <27 kg: 600,000 units (single dose)
   • ≥27 kg: 1,200,000 units (single dose)
   • Useful when oral compliance is a concern
   • Strong recommendation, high-quality evidence

For Patients With Penicillin Allergy:

1. Cephalexin (oral) 1

   • 20 mg/kg twice daily (max 500 mg per dose) for 10 days
   • Strong recommendation, high-quality evidence
   • Note: Avoid in patients with immediate-type hypersensitivity to penicillin

2. Clindamycin (oral) 1

   • 7 mg/kg 3 times daily (max 300 mg per dose) for 10 days
   • Strong recommendation, moderate-quality evidence

3. Macrolides (oral) 1

   • Azithromycin: 12 mg/kg once daily (max 500 mg) for 5 days
   • Clarithromycin: 7.5 mg/kg twice daily (max 250 mg per dose) for 10 days
   • Strong recommendation, moderate-quality evidence
   • Caution: Increasing resistance of GAS to macrolides has been reported

Important Clinical Considerations

1. Duration of therapy:

   • Standard 10-day course for penicillins and most alternatives is recommended
   • Recent evidence suggests that shorter courses (5 days) of penicillin are less effective for GAS eradication 1
   • Exception: Azithromycin is given for 5 days due to its prolonged tissue half-life

2. Treatment failures:

   • Up to 20% of patients may experience bacteriologic failure with penicillin 2
   • For treatment failures, consider:
     • Clindamycin (20-30 mg/kg/day in 2-4 divided doses for 10 days) 1
     • Amoxicillin-clavulanate (40 mg/kg/day in 3 divided doses for 10 days) 1, 3

3. Potential pitfalls:

   • Beta-lactamase-producing bacteria may "shield" GAS from penicillin action 2
   • Poor compliance with 10-day regimens is common
   • Amoxicillin should be avoided in suspected Epstein-Barr virus infections due to risk of severe rash 1
   • Macrolides should not be used as first-line due to increasing resistance 1

Adjunctive Therapy

• Ibuprofen or paracetamol for symptomatic relief 1
• Corticosteroids may be considered in adults with severe presentations (3-4 Centor criteria) but are not routinely recommended 1

Remember that most cases of acute tonsillitis are viral in origin and do not require antibiotic therapy. Appropriate diagnosis and judicious use of antibiotics are essential to prevent antimicrobial resistance.