Treatment of Community-Acquired Pneumonia
For community-acquired pneumonia (CAP), the recommended first-line treatment is a combination of ceftriaxone (1-2 g/day) with a macrolide (preferably azithromycin) for hospitalized patients, or a respiratory fluoroquinolone like levofloxacin for outpatients or those with specific pathogens. 1
Empiric Treatment Based on Setting and Severity
Outpatient Treatment
Mild to moderate CAP without comorbidities:
- Amoxicillin or
- Macrolide (azithromycin 500mg on day 1, then 250mg daily for days 2-5) 2
- Consider doxycycline if atypical pathogens are suspected
Outpatient with comorbidities or risk factors:
- Respiratory fluoroquinolone (levofloxacin 750mg daily for 5 days) 3 or
- Beta-lactam plus macrolide combination
Inpatient (Non-ICU) Treatment
- Preferred regimen: Ceftriaxone (1-2g/day) plus azithromycin 1
- Alternative: Respiratory fluoroquinolone monotherapy (levofloxacin 750mg daily) 3
ICU Treatment
- Preferred regimen: Ceftriaxone combined with either a macrolide or a respiratory fluoroquinolone 1
- If Pseudomonas suspected: Antipseudomonal beta-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin/levofloxacin or an aminoglycoside plus azithromycin 1
- If MRSA suspected: Add vancomycin or linezolid to standard therapy 1
Pathogen-Specific Treatment
| Pathogen | Recommended Treatment |
|---|---|
| Streptococcus pneumoniae | Beta-lactams (amoxicillin, ceftriaxone) [1] |
| Mycoplasma pneumoniae | Macrolide (azithromycin preferred) [1] |
| Legionella spp. | Levofloxacin (preferred), moxifloxacin, or macrolide ± rifampicin [1] |
| Chlamydophila pneumoniae | Doxycycline, macrolide, levofloxacin, or moxifloxacin [1] |
| Pseudomonas aeruginosa | Antipseudomonal beta-lactam plus either fluoroquinolone or aminoglycoside [1] |
Treatment Duration
- Standard uncomplicated CAP: Minimum 5 days when clinical stability is achieved 1
- CAP caused by MRSA or Pseudomonas: 7 days recommended 1
- Levofloxacin high-dose regimen: 750mg daily for 5 days 3
- Azithromycin regimen: 500mg on day 1, then 250mg daily for days 2-5 2
Monitoring and Response Assessment
- Fever should resolve within 2-3 days after starting antibiotics 1
- Treatment failure is indicated by:
- Persistent fever beyond 3 days
- Worsening respiratory symptoms
- Progression of pulmonary infiltrates 1
- Maintain SaO₂ >92% in uncomplicated cases with oxygen supplementation 1
- Monitor vital signs, mental status, and oxygen saturation at least twice daily 1
Switching from IV to Oral Therapy
Switch from IV to oral therapy when patient:
- Is hemodynamically stable
- Shows clinical improvement
- Can ingest medications
- Has a normally functioning gastrointestinal tract 1
Common Pitfalls to Avoid
- Inadequate initial coverage: Ensure empiric therapy covers both typical and atypical pathogens
- Delayed switch from IV to oral: Transition promptly when criteria are met
- Inappropriate duration: Avoid extending treatment beyond recommended duration when patient has achieved clinical stability
- Failure to recognize treatment failure: Reassess if no improvement after 72 hours
- Overuse of antibiotics: Use narrow-spectrum antibiotics when a pathogen is identified 1
Recent evidence suggests that early administration of systemic corticosteroids (within 24 hours) may reduce mortality in severe CAP 4, though this should be considered on a case-by-case basis.