What antibiotic is recommended for bacterial bronchitis?

Antibiotic Treatment for Bacterial Bronchitis

Antibiotics should NOT be routinely prescribed for acute bronchitis in otherwise healthy adults, as bacterial infection is rare and clinical trials show no benefit over placebo. 1, 2

When to Consider Antibiotics

The decision to use antibiotics depends critically on the clinical context:

Healthy Adults with Acute Bronchitis

• Do not prescribe antibiotics - acute bronchitis is predominantly viral, and bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, Bordetella pertussis) are involved only on very rare occasions 1
• The clinical course is spontaneously favorable after approximately 10 days, though cough may persist longer 1
• Important caveat: Purulent sputum or green/yellow sputum does NOT indicate bacterial superinfection and is not an indication for antibiotics 1, 2
• Consider antibiotics only if fever >38°C persists for more than 3-7 days, which suggests bacterial superinfection or pneumonia 1, 2

Patients with Chronic Obstructive Pulmonary Disease (COPD)

For patients with underlying chronic bronchitis and FEV1 between 35-80%, prescribe antibiotics when at least 2 of 3 Anthonisen criteria are present: 2

• Increased sputum volume
• Increased sputum purulence
• Increased dyspnea

For patients with severe chronic respiratory insufficiency (FEV1 <35%), immediate antibiotic therapy is recommended during exacerbations 2

First-Line Antibiotic Choices (When Indicated)

For Suspected Bacterial Bronchitis in COPD Patients

Amoxicillin 3 g/day orally is the first-line treatment for suspected bacterial origin, particularly in adults over 40 years 1, 2

Alternative first-line options:

• Azithromycin (500 mg on day 1, then 250 mg daily for days 2-5) - particularly effective and well-tolerated with clinical cure rates of 85-89% 2, 3, 4, 5
• Macrolides (azithromycin, clarithromycin) - especially for suspected atypical pathogens (Mycoplasma, Chlamydia) in younger adults (<40 years) 1, 2
• First-generation cephalosporins 2

For penicillin allergy:

• Macrolides (azithromycin preferred) 2
• Pristinamycin 2
• Doxycycline 2

Target Pathogens

Antibiotic selection should cover: 2

• Streptococcus pneumoniae
• Haemophilus influenzae
• Moraxella catarrhalis

Second-Line Antibiotic Options

Use second-line antibiotics if first-line therapy fails after 72 hours: 2

• Amoxicillin-clavulanate (625 mg three times daily for 10-14 days) - reference second-line therapy 2, 6
• Second-generation cephalosporins (cefuroxime-axetil) 2
• Third-generation cephalosporins (cefpodoxime-proxetil, cefotiam-hexetil) 2
• Respiratory fluoroquinolones (levofloxacin 500 mg daily for 7 days, moxifloxacin 400 mg daily for 5 days) - particularly effective against resistant pathogens 2, 7, 5

Treatment Duration

• Azithromycin: 5 days (500 mg day 1, then 250 mg days 2-5) 2, 3, 5
• Most other antibiotics: 14 days 1, 2
• Severe infections or elderly with comorbidities: Full 14-day course recommended 6

Monitoring and Follow-Up

• Assess therapeutic efficacy within 72 hours of initiating treatment 1, 2, 6
• Symptoms should decrease within 48-72 hours of effective treatment 1
• Do not change treatment within the first 72 hours unless the patient's clinical state worsens 1, 6

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for acute bronchitis in healthy adults - this is the most common error 1, 2
• Do not assume purulent sputum indicates bacterial infection - sputum color change is NOT diagnostic of bacterial superinfection 1, 2
• Do not use fluoroquinolones as first-line therapy in elderly patients unless specifically indicated, due to serious adverse effect risks 6
• Avoid these antibiotics due to inadequate coverage or poor benefit/risk ratio: 2
  • Ciprofloxacin or ofloxacin (inadequate pneumococcal coverage)
  • Cefixime (inadequate coverage)
  • Cotrimoxazole/trimethoprim-sulfamethoxazole (inconsistent pneumococcal activity, poor benefit/risk ratio)
  • First-generation oral cephalosporins (inadequate activity against penicillin-resistant S. pneumoniae)
• Do not combine aminopenicillin with beta-lactamase inhibitor unless using as second-line therapy - not justified for first-line treatment 1
• Distinguish acute bronchitis from pneumonia - pneumonia requires different management and always requires antibiotics 2

Special Populations

Elderly patients with renal impairment:

• Azithromycin is preferred first-line due to safety in renal impairment 6
• Avoid aminoglycosides (gentamicin, tobramycin) due to nephrotoxicity risk 6
• Amoxicillin/clavulanate 625 mg three times daily for 14 days is an alternative for macrolide contraindications 6