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

Treatment of Community-Acquired Pneumonia

The recommended first-line treatment for community-acquired pneumonia (CAP) is a combination of a β-lactam (such as amoxicillin or ceftriaxone) plus a macrolide (such as azithromycin or clarithromycin), with the specific regimen determined by severity and treatment setting. 1, 2

Treatment Based on Patient Setting and Severity

Outpatient Treatment

• For previously healthy outpatients with no risk factors for drug-resistant pathogens, a macrolide (azithromycin or clarithromycin) is recommended as first-line therapy 1
• The British Thoracic Society recommends amoxicillin at higher doses (1 g every 8 hours) for outpatient treatment 1, 2
• Doxycycline 100 mg twice daily is an alternative first-line option for outpatients without comorbidities 2
• For outpatients with comorbidities or recent antibiotic use, a respiratory fluoroquinolone (levofloxacin) or a β-lactam plus a macrolide is recommended 1, 2

Hospitalized Non-ICU Patients

• A combination of a β-lactam (such as ceftriaxone) plus a macrolide (such as azithromycin) is the preferred regimen 1, 2, 3
• A respiratory fluoroquinolone alone (levofloxacin or moxifloxacin) can be used as an alternative treatment option 2, 4

Severe CAP/ICU Treatment

• For patients without risk factors for Pseudomonas, a β-lactam plus either a macrolide or a respiratory fluoroquinolone is recommended 2
• For patients with risk factors for Pseudomonas, an antipseudomonal β-lactam plus either ciprofloxacin/levofloxacin, or an aminoglycoside plus azithromycin is recommended 2
• Consider adding vancomycin or linezolid when community-acquired MRSA is suspected 2

Duration of Therapy

• Patients with CAP should be treated for a minimum of 5 days 1, 2
• Patients should be afebrile for 48–72 hours and have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy 1, 2
• For uncomplicated S. pneumoniae pneumonia, 7-10 days of treatment is typically sufficient 2
• For severe pneumonia or when specific pathogens like Legionella, staphylococcal, or Gram-negative enteric bacilli are suspected or confirmed, consider extending treatment to 14-21 days 2

Switching from IV to Oral Therapy

• Patients should be switched from intravenous to oral therapy when they are hemodynamically stable and improving clinically 1
• Patients initially treated with parenteral antibiotics should be transferred to an oral regimen as soon as clinical improvement occurs and temperature has been normal for 24 hours 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 1, 2
• All patients with CAP should be tested for COVID-19 and influenza when these viruses are common in the community 3

Common Pitfalls and Caveats

• Overreliance on fluoroquinolones can lead to resistance; they should be reserved for patients with β-lactam allergies or when specifically indicated 2
• Inadequate coverage for atypical pathogens should be avoided, ensuring coverage for Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila 2
• Delaying antibiotic administration is associated with increased mortality, particularly in severe pneumonia 2
• The first antibiotic dose should be administered while still in the emergency department for hospitalized patients 2
• Local antimicrobial susceptibility patterns should guide the choice of empiric therapy, as resistance patterns may vary by region 2

Special Considerations

• For patients who fail to improve as expected, conduct a careful review of the clinical history, examination, prescription chart, and all available investigation results 2
• Consider additional investigations including repeat chest radiograph, CRP, white cell count, and further microbiological testing 2
• Low-tidal-volume ventilation (6 cm³/kg of ideal body weight) is recommended for patients undergoing ventilation who have diffuse bilateral pneumonia or acute respiratory distress syndrome 1
• Systemic corticosteroid administration within 24 hours of development of severe CAP may reduce 28-day mortality 3

Follow-up

• Clinical review should be arranged for all patients at around 6 weeks, either with their general practitioner or in a hospital clinic 1