What are the first line antibiotics for acute bacterial tonsillitis?

First-Line Antibiotics for Acute Bacterial Tonsillitis

Penicillin is the first-line antibiotic treatment for acute bacterial tonsillitis due to its proven efficacy, safety, narrow spectrum, and low cost. 1

Primary Treatment Options

• Penicillin V (oral): First-choice treatment for acute bacterial tonsillitis, particularly effective against Group A β-hemolytic streptococci (GABHS), the most common bacterial cause 1, 2
• Amoxicillin: Often used in younger children instead of penicillin V due to better taste acceptance and availability as syrup/suspension 1
• Amoxicillin-clavulanate: Alternative first-line option, particularly when β-lactamase producing bacteria are suspected 2, 3

Alternative Options for Penicillin-Allergic Patients

• Clindamycin: Preferred alternative for penicillin-allergic patients with excellent gram-positive coverage against Streptococcus pyogenes 4
• First-generation cephalosporins: Good alternative in non-Type I penicillin allergies 1
• Macrolides (azithromycin, clarithromycin, erythromycin): Options for patients with true penicillin allergy, though with lower efficacy rates (77-78%) compared to first-line options 1, 5
• Doxycycline: Alternative option in penicillin-allergic adult patients 1

Treatment Duration and Dosing

• Standard treatment duration is 10 days for penicillin, erythromycin, and clarithromycin 5, 6
• Azithromycin may be given for 5 days due to its prolonged tissue half-life 5
• For children, high-dose amoxicillin (90 mg/kg/day) or amoxicillin-clavulanate (90 mg/6.4 mg per kg/day) is recommended 1

Treatment Failure Management

• If no improvement after 72 hours of initial therapy, consider switching antibiotics 1
• For treatment failures with penicillin:
  • Clindamycin (20-30 mg/kg/day in 3 doses, maximum 300 mg/dose) 4
  • Cephalosporins (cefuroxime axetil, cefpodoxime proxetil) 1
  • Respiratory fluoroquinolones (gatifloxacin, levofloxacin, moxifloxacin) in adults with moderate disease who have recently received antibiotics 4

Special Considerations

• Amoxicillin should be avoided in children with suspected Epstein-Barr virus infection due to risk of severe rash 1
• Group A β-hemolytic streptococci have not developed resistance to penicillins over five decades 1
• Combination therapy may be considered in severe or recurrent cases (e.g., clindamycin plus rifampin) 1, 4

Common Pitfalls

• Failing to distinguish between bacterial and viral tonsillitis (viral causes are more common and don't require antibiotics) 6
• Not completing the full course of antibiotics, particularly with penicillin, which can lead to treatment failure 6
• Using broad-spectrum antibiotics unnecessarily when narrow-spectrum options would be effective 1
• Overlooking the possibility of a carrier state rather than active infection in recurrent cases 4

Monitoring and Follow-up

• Reassess patients who don't respond to initial therapy within 72 hours 1
• Consider further evaluation with cultures if symptoms persist despite appropriate second-line therapy 4
• For truly recurrent tonsillitis meeting specific criteria (7+ episodes in one year or 5+ episodes in each of two consecutive years), tonsillectomy may be considered 6