What are the recommended antibiotics for treating bacterial tonsillitis?

Recommended Antibiotics for Bacterial Tonsillitis

Penicillin V is the first-line antibiotic for confirmed bacterial tonsillitis, dosed at 250 mg twice or three times daily in children, or 250 mg four times daily or 500 mg twice daily in adolescents/adults for 10 days. 1

First-Line Treatment Options

The following antibiotics are recommended as first-line therapy for Group A Streptococcus (GAS) tonsillitis:

Penicillin-Based Regimens

• Penicillin V remains the gold standard due to its proven efficacy, narrow spectrum, safety profile, and low cost, with strong recommendation and high-quality evidence from the Infectious Diseases Society of America. 1, 2

• Amoxicillin is an acceptable alternative to penicillin V, dosed at 50 mg/kg once daily (maximum 1000 mg) or 25 mg/kg twice daily (maximum 500 mg per dose) for 10 days in children, with strong recommendation from the American Academy of Pediatrics. 1, 2

• Benzathine penicillin G as a single intramuscular dose is recommended by the CDC for patients with compliance concerns: 600,000 units for patients <27 kg, and 1,200,000 units for patients ≥27 kg. 1

Critical Treatment Duration

• The 10-day duration is non-negotiable for standard penicillin or amoxicillin regimens to maximize bacterial eradication and prevent rheumatic fever, with the only exception being high-dose penicillin V (800 mg four times daily) which may be given for 5 days. 2, 3, 4

• Short courses of 5 days with standard-dose penicillin are less effective for GAS eradication and should be avoided. 3

Treatment for Penicillin-Allergic Patients

The choice of alternative antibiotic depends on the type of penicillin allergy:

Non-Anaphylactic Penicillin Allergy

• First-generation cephalosporins are preferred for patients without immediate-type hypersensitivity reactions. 1, 2

• Cephalexin 20 mg/kg/dose twice daily (maximum 500 mg/dose) for 10 days. 1, 2

• Cefadroxil 30 mg/kg once daily (maximum 1 g) for 10 days. 1, 2

• Cephalosporins have demonstrated higher clinical cure rates than penicillin in some meta-analyses, though the clinical significance remains debated. 1

Anaphylactic Penicillin Allergy

• Clindamycin 7 mg/kg/dose three times daily (maximum 300 mg/dose) for 10 days is the preferred option for true penicillin allergy. 1, 2

• Azithromycin 12 mg/kg once daily (maximum 500 mg) for 5 days can be used, but macrolide resistance in GAS is a significant concern. 1, 5

• Clarithromycin 7.5 mg/kg/dose twice daily (maximum 250 mg/dose) for 10 days is another macrolide option, with the same resistance concerns. 1

Critical Diagnostic Requirement

• Never prescribe antibiotics without microbiological confirmation of GAS through rapid antigen detection testing (RADT) and/or throat culture. 2, 3

• Use Centor/McIsaac criteria to guide testing: fever ≥38.3°C, tonsillar exudate, tender anterior cervical lymphadenopathy, and absence of cough. 2

• Patients with 0-2 Centor criteria should not receive antibiotics as viral etiology is most likely. 2

Management of Treatment Failure or Recurrent Tonsillitis

For patients with documented GAS tonsillitis recurring within 2 weeks of completing standard therapy:

• Clindamycin 20-30 mg/kg/day in 3 divided doses (maximum 300 mg/dose) for 10 days. 2, 3

• Amoxicillin-clavulanate 40 mg/kg/day (amoxicillin component) in 3 divided doses for 10 days. 2, 3

• Consider that patients may be chronic GAS carriers experiencing intercurrent viral infections rather than true recurrent bacterial infections. 3

Important Pitfalls to Avoid

• Never use broad-spectrum antibiotics when narrow-spectrum penicillins are effective for confirmed GAS. 2, 3

• Never perform follow-up throat cultures on asymptomatic patients who completed appropriate therapy. 2, 3

• Do not rely on ASO titers to guide treatment decisions for acute episodes, as they reflect past immunologic response, not current infection status. 3

• Be aware of macrolide resistance: approximately 1% of azithromycin-susceptible S. pyogenes isolates become resistant following therapy, and susceptibility testing should be performed when using macrolides. 5

• Penicillin remains the drug of choice for prophylaxis of rheumatic fever; data establishing efficacy of azithromycin in subsequent prevention of rheumatic fever are not available. 5