What are the recommended antibiotics for treating simple pneumonia?

Recommended Antibiotics for Simple Pneumonia

For simple community-acquired pneumonia in adults, the first-line treatment is oral amoxicillin 3 g/day for pneumococcal pneumonia, or a macrolide (such as azithromycin) for atypical pneumonia. 1

Adult Treatment Algorithm

Outpatient Treatment (Adults)

1. Suspected pneumococcal pneumonia (especially in adults over 40 years):

   • Amoxicillin 3 g/day orally 1
   • Duration: 7-8 days (should not exceed 8 days in responding patients) 1

2. Suspected atypical pneumonia (adults under 40 years, within epidemic context):

   • Azithromycin 500 mg once daily for 3 days 1, 2
   • Alternative: Clarithromycin 500 mg twice daily 1
   • Duration: 3-5 days for azithromycin; 7-8 days for other macrolides 3, 4

3. Alternative when pathogen is uncertain:

   • Respiratory fluoroquinolone (levofloxacin 750 mg daily for 5 days or moxifloxacin) 1, 5
   • Telithromycin (alternative to first-line treatments) 1

Hospitalized Patients (Non-ICU)

• Non-antipseudomonal cephalosporin (ceftriaxone/cefotaxime) + macrolide 1
• OR Respiratory fluoroquinolone (moxifloxacin or levofloxacin) 1
• Duration: 7-8 days in responding patients 1

Severe Pneumonia (ICU)

• No risk for Pseudomonas: Non-antipseudomonal cephalosporin + macrolide OR respiratory fluoroquinolone 1
• Risk for Pseudomonas: Antipseudomonal agent (cephalosporin, acylureidopenicillin/β-lactamase inhibitor, or carbapenem) PLUS ciprofloxacin OR macrolide + aminoglycoside 1

Pediatric Treatment Algorithm

Outpatient Treatment (Children)

1. Children < 5 years old:

   • Amoxicillin 90 mg/kg/day in 2 doses 1
   • Duration: 7-14 days 1

2. Children ≥ 5 years old:

   • Amoxicillin 90 mg/kg/day in 2 doses (max 4 g/day) 1
   • For suspected atypical pneumonia: Add azithromycin (10 mg/kg on day 1, then 5 mg/kg/day for days 2-5) 1

Hospitalized Children

• Fully immunized: Ampicillin or penicillin G 1
• Not fully immunized: Ceftriaxone or cefotaxime 1
• Add azithromycin if atypical pneumonia suspected 1

Special Considerations

Aspiration Pneumonia

• First-line: Amoxicillin-clavulanate (1-2g PO q12h or 1.2g IV q8h) 6
• Alternatives: Clindamycin + cephalosporin, or moxifloxacin 1, 6

Treatment Monitoring

• Assess clinical response within 48-72 hours 1
• Do not change treatment within first 72 hours unless clinical worsening 1
• Consider treatment failure if no improvement after 72 hours 6
• Measure C-reactive protein on days 1 and 3/4 to assess response 6

Switching from IV to Oral Therapy

• Switch to oral treatment when clinically stable 1
• Early mobilization is recommended for all patients 1
• Low molecular weight heparin should be given to patients with acute respiratory failure 1

Important Caveats

• Antibiotics should NOT be prescribed for acute bronchitis in healthy adults 1
• Macrolides are preferred for atypical pneumonia due to their effectiveness against Mycoplasma, Chlamydia, and Legionella 7
• Recent studies show shorter antibiotic courses (≤7 days) are as effective as longer courses for uncomplicated pneumonia 6
• For penicillin-allergic patients, consider respiratory fluoroquinolones or macrolides 1
• Resistance patterns should be considered when selecting empiric therapy, particularly for S. pneumoniae 8, 5

By following this evidence-based approach to antibiotic selection for simple pneumonia, clinicians can provide effective treatment while minimizing antibiotic resistance and adverse effects.