What is the recommended treatment for Community-Acquired Pneumonia (CAP)?

Treatment of Community-Acquired Pneumonia (CAP)

The recommended treatment for Community-Acquired Pneumonia should be based on severity assessment, with specific antibiotic regimens tailored to outpatient, non-ICU inpatient, or ICU settings to optimize outcomes related to morbidity, mortality, and quality of life. 1

Initial Assessment and Management

• Severity assessment should guide the decision for outpatient versus inpatient treatment, using tools like CURB-65 or Pneumonia PORT Severity Index (PSI) 2, 1
• For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED 2, 1
• Empiric antibiotic therapy should be initiated promptly in adults with clinically suspected and radiographically confirmed CAP 1

Outpatient Treatment

Previously Healthy Patients

• For previously healthy patients with no recent antibiotic use:
  • A macrolide (azithromycin or clarithromycin) or doxycycline is recommended 2
  • Azithromycin dosing: 500 mg on day 1, followed by 250 mg daily for days 2-5 3

Patients with Comorbidities or Recent Antibiotic Use

• For patients with comorbidities (COPD, diabetes, heart failure, etc.) or recent antibiotic use:
  • A respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin 750 mg) as monotherapy 2
  • OR a β-lactam plus a macrolide 2, 1
  • Preferred β-lactams include high-dose amoxicillin (1 g three times daily) or amoxicillin-clavulanate (2 g twice daily) 2

Non-ICU Inpatient Treatment

• For hospitalized non-ICU patients:
  • A respiratory fluoroquinolone (e.g., levofloxacin) as monotherapy 2, 1
  • OR a β-lactam (cefotaxime, ceftriaxone, or ampicillin) plus a macrolide 2, 1
  • For penicillin-allergic patients, a respiratory fluoroquinolone is recommended 2

ICU Treatment

• For severe CAP requiring ICU admission:
  • A β-lactam (cefotaxime, ceftriaxone, or ampicillin-sulbactam) plus either azithromycin or a respiratory fluoroquinolone 2, 1
  • For penicillin-allergic patients, aztreonam plus a respiratory fluoroquinolone is recommended 2

Special Considerations in ICU

• For suspected Pseudomonas infection:

  • An antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin/levofloxacin or an aminoglycoside plus azithromycin 2, 1

• For suspected community-acquired MRSA:

  • Add vancomycin or linezolid to the standard regimen 2, 1

Duration of Therapy

• Patients with CAP should be treated for a minimum of 5 days 2, 1
• Patients should be afebrile for 48-72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy 2, 1
• Longer duration may be needed if initial therapy was not active against the identified pathogen or if complicated by extrapulmonary infection 2, 1

IV to Oral Switch Criteria

• Patients should be switched from intravenous to oral therapy when they are:
  • Hemodynamically stable and improving clinically 2
  • Able to ingest medications with a normally functioning gastrointestinal tract 2, 1
  • Patients should be discharged as soon as they are clinically stable 2

Pathogen-Directed Therapy

• Once the etiology of CAP has been identified using reliable microbiological methods, antimicrobial therapy should be directed at that specific pathogen 2, 1
• Early treatment (within 48 hours of symptom onset) is recommended for optimal outcomes 1

Special Considerations

• For patients with hypoxemia or respiratory distress, consider a trial of noninvasive ventilation unless immediate intubation is required 2, 1
• Low-tidal-volume ventilation (6 cm³/kg of ideal body weight) should be used for patients with diffuse bilateral pneumonia or ARDS 2, 1
• Patients with persistent septic shock despite fluid resuscitation should be considered for additional supportive therapies 2, 1

Follow-up

• Clinical review should be arranged for all patients at around 6 weeks 2, 1
• A follow-up chest radiograph should be obtained for patients with persistent symptoms or those at higher risk of underlying malignancy (especially smokers and those over 50 years) 2, 1

Common Pitfalls and Caveats

• In regions with high rates (>25%) of high-level macrolide-resistant S. pneumoniae, avoid macrolide monotherapy 2
• Fluoroquinolones should be used judiciously to prevent development of resistance 4, 5
• Failure to recognize severity can lead to inappropriate site-of-care decisions and inadequate initial therapy 2, 1
• Delayed antibiotic administration in severe CAP is associated with increased mortality 2, 6