What is the recommended first-line antibiotic treatment for acute tonsillitis?

First-Line Antibiotic Treatment for Acute Tonsillitis

Penicillin is the first-choice antibiotic for acute tonsillitis caused by Group A Streptococcus, due to its proven efficacy, safety, narrow spectrum, and low cost. 1

Diagnostic Approach

Before initiating antibiotic therapy, it's important to determine if the tonsillitis is bacterial or viral:

• Centor criteria can help assess the likelihood of bacterial pharyngitis:

  • Fever >38°C
  • Tonsillar exudates
  • Tender anterior cervical lymphadenopathy
  • Absence of cough
  • 3-4 criteria suggest higher probability of streptococcal infection

• Testing considerations:

  • Rapid antigen detection tests have low sensitivity but high specificity
  • Throat cultures are more sensitive but take longer for results

First-Line Treatment Options

For patients without penicillin allergy:

• 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

• Amoxicillin (oral) 1

  • 50 mg/kg once daily (maximum 1000 mg)
  • Alternative: 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days

• Benzathine penicillin G (intramuscular) 1

  • <27 kg: 600,000 U single dose
  • ≥27 kg: 1,200,000 U single dose

Alternative Treatment Options (Penicillin Allergy)

For patients with penicillin allergy, alternatives include:

• Cephalexin (if non-immediate hypersensitivity): 20 mg/kg twice daily (max 500 mg/dose) for 10 days 1
• Clindamycin: 7 mg/kg 3 times daily (max 300 mg/dose) for 10 days 1
• Macrolides (e.g., azithromycin, clarithromycin): Consider only when absolutely necessary due to increasing resistance 1, 2

Treatment Duration

A full 10-day course of antibiotics is recommended for penicillin, amoxicillin, and most alternatives to:

• Prevent acute rheumatic fever
• Reduce risk of suppurative complications
• Ensure bacterial eradication 3

While shorter courses with newer antibiotics (3-5 days with azithromycin) may provide similar symptom relief, only the 10-day therapy has proven effective in preventing rheumatic fever and glomerulonephritis 3.

Important Considerations

• Delayed prescribing is a valid option for less severe presentations (0-2 Centor criteria) 1

• Symptomatic treatment is important regardless of antibiotic use:

  • NSAIDs or acetaminophen for pain/fever
  • Adequate hydration
  • Rest

• Treatment failure: If no improvement after 48-72 hours, reassess diagnosis and consider changing antibiotics 1

Pitfalls to Avoid

1. Overtreatment: Not all sore throats require antibiotics; viral causes are common
2. Undertreatment: Failing to treat streptococcal pharyngitis can lead to complications
3. Inappropriate antibiotic selection: Using broad-spectrum antibiotics when narrow-spectrum would suffice
4. Inadequate duration: Shorter courses may not prevent complications
5. Ignoring resistance patterns: Local resistance patterns should guide therapy when available

Special Populations

• Carriers: Chronic streptococcal carriers generally don't require treatment unless specific circumstances exist 1
• Recurrent tonsillitis: May require consideration of tonsillectomy if meeting Paradise criteria (≥7 episodes in past year or ≥5 episodes per year for 2 consecutive years) 3

Remember that penicillin has remained effective against Group A Streptococcus for decades with no significant development of resistance, making it the optimal first-line choice for acute tonsillitis.