What is the best antibiotic for a patient with streptococcal (GABHS) pharyngitis and bronchitis?

Treatment of Strep Throat with Bronchitis

Penicillin or amoxicillin remains the best antibiotic choice for streptococcal pharyngitis, even when bronchitis is present, as bronchitis is typically viral and does not require antibiotic treatment. 1

Key Clinical Principle

The presence of bronchitis alongside strep throat does not change the antibiotic selection, because:

• Acute bronchitis is overwhelmingly viral and antibiotics provide no benefit for the bronchitis component 1
• Group A streptococcal pharyngitis requires targeted treatment with narrow-spectrum antibiotics 1
• Broad-spectrum antibiotics should be avoided as they increase antibiotic resistance without additional clinical benefit 1

First-Line Treatment Recommendation

Penicillin or amoxicillin for 10 days is the treatment of choice based on: 1

• Proven efficacy and safety 1
• Narrow spectrum of activity 1
• Low cost 1
• No documented penicillin resistance in Group A streptococcus ever 1, 2

Specific Dosing Options:

• Amoxicillin 50 mg/kg once daily (maximum 1000 mg) for 10 days offers the advantage of once-daily dosing, which enhances adherence 1, 3
• Penicillin V given 2-3 times daily for 10 days is equally effective 1
• Intramuscular benzathine penicillin G as a single dose for patients unlikely to complete oral therapy 1

For Penicillin-Allergic Patients

Non-Anaphylactic Allergy:

First-generation cephalosporins for 10 days (cephalexin or cefadroxil): 1, 3

• Narrow-spectrum cephalosporins are strongly preferred over broad-spectrum agents 1, 3
• Avoid broad-spectrum cephalosporins (cefuroxime, cefixime, cefdinir, cefpodoxime) as they unnecessarily select for resistant organisms 1, 3
• Up to 10% of penicillin-allergic patients are also allergic to cephalosporins 1, 2

Anaphylactic Penicillin Allergy:

Alternative options include: 1

• Clindamycin for 10 days (resistance rate approximately 1% in the US) 1
• Clarithromycin for 10 days 1
• Azithromycin for 5 days (12 mg/kg/day, maximum 500 mg) 1

Important caveat: Macrolide resistance rates in the US are approximately 5-8%, making them less reliable than clindamycin 1, 2

Critical Pitfalls to Avoid

Do not use broad-spectrum antibiotics thinking they will "cover both infections": 1

• Bronchitis does not benefit from antibiotics 1
• Broad-spectrum agents increase antibiotic resistance without improving outcomes 1
• They are more expensive and have more side effects 1

Do not use the following antibiotics for strep throat: 1

• Tetracyclines (high resistance rates) 1
• Sulfonamides or trimethoprim-sulfamethoxazole (do not eradicate Group A strep) 1
• Older fluoroquinolones like ciprofloxacin (limited activity against Group A strep) 1

Duration of Therapy

10 days of treatment is required for most antibiotics to achieve maximal pharyngeal eradication of Group A streptococcus: 1

• Azithromycin is the exception (5 days approved by FDA) 1, 4
• Shorter courses with some cephalosporins have been studied but cannot be endorsed due to methodological concerns 1

Expected Clinical Response

Symptom improvement should occur within 24-48 hours of starting appropriate antibiotic therapy: 1

• If no improvement by 48-72 hours, consider treatment failure or alternative diagnosis 1
• The bronchitis symptoms (cough, chest discomfort) will resolve on their own over 1-3 weeks regardless of antibiotic use 1