What is the recommended antibiotic regimen for tonsillitis?

Antibiotic Regimen for Tonsillitis

For bacterial tonsillitis caused by Group A Streptococcus, prescribe penicillin V 250 mg twice daily (or three times daily) for children, or 500 mg twice daily (or 250 mg four times daily) for adolescents and adults, for a full 10-day course. 1, 2

First-Line Treatment Options

Penicillin-based regimens are the gold standard due to their narrow spectrum, proven efficacy in preventing rheumatic fever, minimal adverse effects, and low cost. 1, 2

Standard Penicillin Regimens (10 days):

• Penicillin V (oral): Children: 250 mg 2-3 times daily; Adolescents/Adults: 500 mg twice daily or 250 mg four times daily 1, 2
• Amoxicillin (oral): 50 mg/kg once daily (maximum 1000 mg) OR 25 mg/kg twice daily (maximum 500 mg) 1, 2
• Benzathine penicillin G (intramuscular): Single dose of 600,000 U for patients <27 kg; 1,200,000 U for patients ≥27 kg 1, 2

The 10-day duration is critical for maximizing bacterial eradication and preventing both suppurative complications (peritonsillar abscess, cervical lymphadenitis) and non-suppurative complications (acute rheumatic fever, post-streptococcal glomerulonephritis). 1, 3

Evidence on Dosing Frequency:

• Twice-daily penicillin V dosing is as effective as more frequent dosing (three or four times daily), which significantly improves compliance. 4, 5
• Once-daily penicillin is inferior and associated with cure rates 12 percentage points lower than more frequent dosing, so it should not be used. 5
• Once-daily amoxicillin is effective, making it an excellent alternative for improving adherence. 1, 5

Treatment for Penicillin-Allergic Patients

For patients with documented penicillin allergy, the choice depends on the type of allergic reaction:

Non-Immediate Hypersensitivity (10 days):

• Cephalexin (oral): 20 mg/kg/dose twice daily (maximum 500 mg/dose) 1, 2
• Cefadroxil (oral): 30 mg/kg once daily (maximum 1 g) 1, 2

Avoid cephalosporins in patients with immediate-type (Type I) hypersensitivity to penicillin due to cross-reactivity risk. 1, 2

Immediate Hypersensitivity or Cephalosporin Intolerance:

• Clindamycin (oral): 7 mg/kg/dose three times daily (maximum 300 mg/dose) for 10 days 1, 2
• Azithromycin (oral): 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 2, 6
• Clarithromycin (oral): 7.5 mg/kg/dose twice daily (maximum 250 mg/dose) for 10 days 1, 2

Critical caveat: Macrolide resistance in Group A Streptococcus varies geographically and temporally, so these agents should be reserved for true penicillin allergy situations. 1, 2

Duration Considerations

Standard-dose penicillin must be given for 10 days. 1 Recent evidence shows:

• 5-day courses of standard-dose penicillin are less effective (OR 0.43; 95% CI 0.23-0.82) for bacterial eradication. 1
• High-dose penicillin (four times daily for 5 days, total 16g) showed non-inferior clinical cure (89.6% vs 93.3%) compared to standard 10-day therapy, though bacterial eradication was lower. 1
• Short-course cephalosporins (5 days) have better microbial eradication than 10-day penicillin (OR 1.60; 95% CI 1.13-2.27), though this approach requires further validation. 1

The 10-day duration cannot be shortened for standard penicillin regimens because studies addressing rare but serious complications like rheumatic fever require the full course. 1

Common Pitfalls to Avoid

• Never initiate antibiotics without confirming Group A Streptococcus infection through rapid antigen detection testing (RADT) or throat culture. 3
• Do not use once-daily penicillin—it has inferior efficacy compared to twice-daily or more frequent dosing. 5
• Avoid prescribing less than 10 days of standard-dose penicillin or amoxicillin, as this increases treatment failure risk and does not prevent rheumatic fever. 1, 3
• Do not routinely perform follow-up throat cultures in asymptomatic patients who completed appropriate therapy. 1, 3
• Do not use macrolides as first-line agents due to increasing resistance patterns; reserve them strictly for documented penicillin allergy. 1, 2
• Avoid broad-spectrum antibiotics when narrow-spectrum penicillins are effective for confirmed GAS. 3

Adjunctive Therapy

• Provide analgesics or antipyretics (acetaminophen or NSAIDs) for moderate to severe symptoms or high fever. 1
• Never use aspirin in children due to Reye's syndrome risk. 1
• Do not prescribe corticosteroids for routine Group A streptococcal pharyngitis treatment. 1

Chronic Carriers

GAS carriers do not ordinarily require identification or antimicrobial therapy because they are unlikely to spread infection and are at minimal risk for complications. 1 Treatment may be considered only in specific circumstances: community outbreaks, family history of rheumatic fever, or excessive patient anxiety. 1