What is the treatment for community-acquired pneumonia (CAP)?

Treatment for Community-Acquired Pneumonia

The treatment for community-acquired pneumonia (CAP) should be stratified based on severity and setting, with outpatients receiving either a macrolide or doxycycline, non-ICU inpatients receiving a beta-lactam plus macrolide combination or a respiratory fluoroquinolone, and ICU patients receiving a beta-lactam plus either azithromycin or a respiratory fluoroquinolone. 1

Treatment Algorithm Based on Setting and Severity

Outpatient Treatment

• First-line options:
  • Macrolide (azithromycin preferred) for patients without comorbidities or risk factors for drug-resistant S. pneumoniae (DRSP) 1
  • Doxycycline as an alternative for macrolide-allergic patients 2
  • Amoxicillin-clavulanate or respiratory fluoroquinolone for patients with comorbidities or risk factors for DRSP 1

Non-ICU Inpatient Treatment

• First-line options:
  • Beta-lactam (ceftriaxone, cefotaxime, ampicillin-sulbactam) plus a macrolide (azithromycin) 2, 1
  • Respiratory fluoroquinolone monotherapy (levofloxacin, moxifloxacin) 1, 3
  • For patients with beta-lactam allergies: respiratory fluoroquinolone 1

ICU Treatment (Severe CAP)

• Without Pseudomonas risk:

  • Beta-lactam (ceftriaxone, cefotaxime) plus either azithromycin or a respiratory fluoroquinolone 2

• With Pseudomonas risk:

  • Antipseudomonal beta-lactam (cefepime, piperacillin-tazobactam, imipenem, meropenem) plus either:
    • Ciprofloxacin (for antipseudomonal coverage), or
    • Aminoglycoside plus azithromycin or respiratory fluoroquinolone 2, 1

Pathogen-Specific Considerations

• S. pneumoniae: Beta-lactams (amoxicillin, ceftriaxone, cefotaxime) 1
• H. influenzae: Amoxicillin-clavulanate, second/third-generation cephalosporins (except cefixime) 1
• Atypical pathogens (Mycoplasma, Legionella, Chlamydophila): Macrolides, doxycycline, or respiratory fluoroquinolones 1
• MRSA: Add vancomycin or linezolid to standard therapy if suspected 1

Duration of Therapy

• Standard uncomplicated CAP: Minimum 5 days when clinical stability is achieved 1
• Severe CAP or specific pathogens:
  • MRSA or Pseudomonas: 7 days 1
  • Standard therapy: 7-10 days total 2, 4

Switching from IV to Oral Therapy

Patients can be switched from IV to oral therapy when they are:

• Hemodynamically stable
• Clinically improving
• Able to take oral medications
• Have a normally functioning gastrointestinal tract 1

Clinical Monitoring

• Fever should resolve within 2-3 days after starting antibiotics
• Treatment failure is indicated by persistent fever beyond 3 days, worsening respiratory symptoms, or progression of pulmonary infiltrates 1
• Maintain oxygen saturation >92% in uncomplicated cases 1

Common Pitfalls to Avoid

1. Inadequate initial coverage: Ensure coverage for both typical and atypical pathogens
2. Inappropriate antibiotic selection: Cefixime should not be used for respiratory infections due to poor activity against S. pneumoniae 1
3. Delayed switch from IV to oral therapy: Switch when clinically appropriate to reduce costs and complications
4. Excessive treatment duration: Most patients need only 5-7 days of therapy when clinically stable 1, 4
5. Failure to recognize treatment failure: Reassess if no improvement after 72 hours 1

Special Considerations

• High-dose, short-course levofloxacin (750 mg daily for 5 days) is as effective as standard dosing (500 mg daily for 10 days) for CAP 3, 5
• Doxycycline has been shown to be cost-effective compared to levofloxacin for hospitalized patients with non-severe CAP, though concerns exist about potential resistance development 2, 6
• Consider corticosteroids within 24 hours for severe CAP as they may reduce mortality 4

The evidence strongly supports a stratified approach to CAP treatment based on severity and setting, with combination therapy for more severe cases and consideration of local resistance patterns when selecting empiric therapy.