What are the treatment options for bacterial pharyngitis?

Treatment Options for Bacterial Pharyngitis

Penicillin or amoxicillin remains the first-line treatment for bacterial pharyngitis caused by Group A Streptococcus, with a mandatory 10-day course to prevent acute rheumatic fever and achieve maximal bacterial eradication. 1, 2

First-Line Treatment Regimens

For patients without penicillin allergy:

• Penicillin V: 250 mg four times daily OR 500 mg twice daily for 10 days in adolescents and adults 1, 2
• Amoxicillin: 50 mg/kg once daily (maximum 1000 mg) for 10 days, often preferred in children due to better palatability and once-daily dosing that enhances adherence 1, 2
• Intramuscular benzathine penicillin G: Single dose (600,000 units if <27 kg; 1,200,000 units if ≥27 kg) when oral adherence is uncertain 1, 2

Penicillin is preferred because of its proven efficacy, narrow spectrum, safety profile, low cost, and the fact that penicillin-resistant Group A Streptococcus has never been documented anywhere in the world 1. The full 10-day course is essential—shorter courses increase treatment failure rates and risk of acute rheumatic fever 1, 3.

Treatment for Penicillin-Allergic Patients

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

Non-Immediate (Non-Anaphylactic) Penicillin Allergy

First-generation cephalosporins are the preferred alternatives with strong, high-quality evidence supporting their use 1, 4:

• Cephalexin: 20 mg/kg per dose twice daily (maximum 500 mg per dose) for 10 days in children; 500 mg twice daily for 10 days in adults 1, 4
• Cefadroxil: 30 mg/kg once daily (maximum 1 gram) for 10 days 1, 4

The cross-reactivity risk with first-generation cephalosporins is only 0.1% in patients with non-severe, delayed penicillin reactions 4. These agents maintain a narrow spectrum, proven efficacy, and reasonable cost 1.

Immediate/Anaphylactic Penicillin Allergy

For patients with immediate hypersensitivity reactions (anaphylaxis, angioedema, urticaria within 1 hour), ALL beta-lactam antibiotics must be avoided due to up to 10% cross-reactivity risk 1, 4:

• Clindamycin (preferred): 7 mg/kg per dose three times daily (maximum 300 mg per dose) for 10 days in children; 300 mg three times daily for 10 days in adults 1, 4

  • Clindamycin has strong, moderate-quality evidence with approximately 1% resistance among Group A Streptococcus in the United States 1, 4
  • Particularly effective in chronic carriers and treatment failures 1, 4

• Azithromycin: 12 mg/kg once daily (maximum 500 mg) for 5 days 1, 4, 5

  • The ONLY antibiotic requiring just 5 days due to prolonged tissue half-life 1, 3
  • Macrolide resistance is 5-8% in the United States and varies geographically 1, 4
  • Should be reserved for patients who cannot tolerate clindamycin or first-generation cephalosporins 4

• Clarithromycin: 7.5 mg/kg per dose twice daily (maximum 250 mg per dose) for 10 days 1, 4

  • Similar resistance concerns as azithromycin 4

Critical Treatment Duration Requirements

All antibiotics except azithromycin require a full 10-day course to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever 1, 2, 3. Shortening the course by even a few days results in appreciable increases in treatment failure rates 3. The 10-day duration is essential because the primary goal is not just symptomatic improvement but prevention of acute rheumatic fever, which requires adequate bacterial eradication 3.

Antibiotics NOT Recommended

The following should NOT be used for bacterial pharyngitis:

• Tetracyclines: High prevalence of resistant strains 1
• Sulfonamides and trimethoprim-sulfamethoxazole: Do not eradicate Group A Streptococcus 1, 4
• Older fluoroquinolones (ciprofloxacin): Limited activity against Group A Streptococcus 1
• Newer fluoroquinolones (levofloxacin, moxifloxacin): Unnecessarily broad spectrum and expensive 1

Diagnostic Confirmation Required

Treatment should only be initiated after confirming Group A Streptococcus infection through rapid antigen detection test (RADT) or throat culture 1, 3. A positive RADT is diagnostic and does not require backup culture, but a negative RADT in children and adolescents should be followed by throat culture 3. Clinical features alone cannot reliably distinguish bacterial from viral pharyngitis 1, 3.

Adjunctive Therapy

For symptomatic relief:

• Acetaminophen or NSAIDs (ibuprofen) for moderate to severe symptoms or high fever 1, 4, 3
• Aspirin must be avoided in children due to risk of Reye syndrome 1, 4, 3
• Corticosteroids are NOT recommended as adjunctive therapy 1, 4

Common Pitfalls to Avoid

• Do not prescribe antibiotics without diagnostic confirmation—most pharyngitis is viral 1, 3
• Do not use cephalosporins in patients with immediate/anaphylactic penicillin reactions due to 10% cross-reactivity risk 1, 4
• Do not shorten treatment courses below 10 days (except azithromycin's 5-day regimen) as this increases treatment failure and rheumatic fever risk 1, 3
• Do not prescribe broad-spectrum cephalosporins (cefdinir, cefpodoxime, cefixime) when narrow-spectrum agents are appropriate—they are more expensive and select for resistant flora 1
• Do not use azithromycin as first-line therapy—reserve it for penicillin-allergic patients who cannot use other alternatives 4
• Do not perform routine post-treatment throat cultures in asymptomatic patients who have completed therapy 1, 3

Treatment Failures and Recurrent Infections

If treatment fails despite adequate compliance:

• Retreatment with the same regimen is acceptable if compliance was good 1, 2
• For chronic carriers or multiple failures: Clindamycin 20-30 mg/kg per day in three doses (maximum 300 mg per dose) for 10 days 1, 2
• Alternative regimens for recurrent infections: Amoxicillin-clavulanic acid (40 mg/kg/day in 3 divided doses for children; 500 mg twice daily for adults) for 10 days 1
• Benzathine penicillin G with rifampin (20 mg/kg/day in 2 divided doses for 4 days, maximum 600 mg/day) may achieve high eradication rates 1

When multiple episodes occur over months or years, it may be difficult to differentiate viral infections in a chronic carrier from true Group A Streptococcal infections 1. Chronic carriers generally do not require treatment as they are unlikely to spread infection or develop complications 4.