What antibiotics can be given to a patient with suspected bacterial tonsillitis?

Antibiotic Treatment for Suspected Bacterial Tonsillitis

Penicillin V remains the first-line antibiotic for suspected bacterial tonsillitis, administered as 250 mg twice or three times daily in children or 250 mg three to four times daily (or 500 mg twice daily) in adolescents and adults for 10 days. 1

First-Line Treatment Options

For Non-Allergic Patients

• Penicillin V is the drug of choice due to its proven efficacy, safety, narrow spectrum, universal susceptibility of Group A Streptococcus, and low cost 1, 2
• Amoxicillin is an acceptable alternative to penicillin V, particularly in young children who may better tolerate the taste of the suspension, with equivalent efficacy 1, 2
• All oral antibiotics must be administered for 10 days to achieve maximal pharyngeal eradication of Group A streptococci and prevent complications like acute rheumatic fever 1, 3
• Intramuscular benzathine penicillin G (1.2 million units as a single dose) is preferred for patients unlikely to complete a full 10-day oral course 1

For Penicillin-Allergic Patients

• For non-anaphylactic penicillin allergy: First-generation cephalosporins (cephalexin, cefadroxil) for 10 days are recommended 1, 3
• For anaphylactic or immediate hypersensitivity to β-lactams: Use macrolides (azithromycin, clarithromycin) or clindamycin 1, 3
• Erythromycin estolate (20-40 mg/kg/day divided 2-3 times daily) or erythromycin ethylsuccinate (40 mg/kg/day divided 2-3 times daily) for 10 days are suitable alternatives 1
• Azithromycin is FDA-approved as an alternative to first-line therapy in individuals who cannot use first-line agents, though it should not be relied upon as first-line treatment 4

Important Clinical Considerations

Testing Before Treatment

• Antibiotics should only be prescribed for confirmed bacterial tonsillitis using rapid antigen detection testing (RADT) and/or throat culture for Group A Streptococcus 1, 3
• Do not initiate antibiotics based on clinical presentation alone, as viral and bacterial tonsillitis cannot be reliably differentiated on clinical grounds 1, 3

Duration Pitfalls

• Short courses (5 days) of standard-dose penicillin are less effective for Group A Streptococcus eradication and should be avoided 3
• While some newer agents (azithromycin, certain cephalosporins) have been studied in shorter courses, the 10-day regimen remains the standard recommendation due to lack of comprehensive data on shorter courses 1

Second-Line Treatment for Treatment Failures

When to Consider Alternative Antibiotics

• If symptoms return within 2 weeks of completing standard therapy, consider treatment failure, chronic carriage with intercurrent viral infection, or reinfection 1, 3
• For documented treatment failures or recurrent episodes, use one of the following regimens 1, 2, 3:
  • Clindamycin: 20-30 mg/kg/day in 3 doses (maximum 300 mg/dose) for 10 days
  • Amoxicillin-clavulanate (Augmentin): 40 mg amoxicillin/kg/day in 3 doses (maximum 2000 mg amoxicillin/day) for 10 days
  • Penicillin V plus rifampin: Penicillin V 50 mg/kg/day in 4 doses for 10 days PLUS rifampin 20 mg/kg/day in 1 dose for the last 4 days

Chronic Carriers

• Approximately 20% of asymptomatic school-age children may be Group A Streptococcus carriers during winter and spring 1, 3
• Chronic carriers experiencing intercurrent viral pharyngitis may test positive for Group A Streptococcus but do not require repeated antibiotic courses 1, 3
• Antimicrobial therapy for chronic carriers is only indicated in special circumstances such as community outbreaks of acute rheumatic fever or family history of acute rheumatic fever 1

Common Pitfalls to Avoid

• Never prescribe antibiotics without microbiological confirmation of Group A Streptococcus infection 1, 3
• Never use broad-spectrum antibiotics when narrow-spectrum penicillin is effective for confirmed Group A Streptococcus 1
• Never prescribe courses shorter than 10 days for standard penicillin or amoxicillin therapy, as this increases treatment failure risk 1, 3
• Do not obtain follow-up throat cultures in asymptomatic patients who completed appropriate therapy 1, 3
• Do not use ASO titers to guide acute treatment decisions, as they reflect past immunologic response rather than current infection 3