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

Treatment of Community-Acquired Pneumonia

The treatment of community-acquired pneumonia (CAP) should be based on severity assessment, with empiric antibiotic therapy tailored to the likely pathogens and initiated promptly, using a combination of amoxicillin and a macrolide for hospitalized patients with non-severe CAP, or a β-lactam plus either a macrolide or respiratory fluoroquinolone for severe CAP requiring ICU admission. 1

Initial Assessment and Management

• Severity assessment should guide the decision between outpatient versus inpatient treatment, with tools like CURB-65 helping identify patients who can be safely treated as outpatients 1
• For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED to minimize time to treatment 1
• Empiric antibiotic therapy should be initiated in adults with clinically suspected and radiographically confirmed CAP regardless of initial serum procalcitonin level 1

Outpatient Treatment

• For previously healthy outpatients with no recent antibiotic therapy:

  • A macrolide (erythromycin or clarithromycin) or doxycycline is recommended 2, 1

• For outpatients with comorbidities (COPD, diabetes, renal or congestive heart failure, or malignancy) or recent antibiotic therapy:

  • An advanced macrolide (clarithromycin) or a respiratory fluoroquinolone (levofloxacin) is recommended 2
  • Alternatively, an advanced macrolide plus a β-lactam (high-dose amoxicillin or amoxicillin-clavulanate) can be used 2

• For suspected aspiration with infection:

  • Amoxicillin-clavulanate or clindamycin is recommended 2

Non-Severe Inpatient Treatment

• Combined oral therapy with amoxicillin and a macrolide (erythromycin or clarithromycin) is preferred for patients requiring hospital admission for clinical reasons 2, 1
• Most non-severe inpatients can be adequately treated with oral antibiotics 2
• When oral treatment is contraindicated, recommended parenteral choices include intravenous ampicillin or benzylpenicillin, together with erythromycin or clarithromycin 2
• A respiratory fluoroquinolone (levofloxacin) may provide a useful alternative for those intolerant of penicillins or macrolides or where there are concerns about Clostridium difficile associated diarrhea 2

Severe Inpatient Treatment

• Patients with severe pneumonia should be treated immediately after diagnosis with parenteral antibiotics 2
• An intravenous combination of a broad-spectrum β-lactamase stable antibiotic (co-amoxiclav, cefuroxime, cefotaxime, or ceftriaxone) together with a macrolide (clarithromycin or erythromycin) is preferred 2, 1
• For patients intolerant of β-lactams or macrolides, a fluoroquinolone with enhanced activity against S. pneumoniae (levofloxacin) together with intravenous benzylpenicillin is an alternative 2
• For Pseudomonas infection, use an antipneumococcal, antipseudomonal β-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin or levofloxacin 2, 1

Special Considerations

Multi-Drug Resistant Streptococcus pneumoniae (MDRSP)

• Levofloxacin is effective for CAP caused by MDRSP (isolates resistant to two or more of: penicillin, 2nd generation cephalosporins, macrolides, tetracyclines, and trimethoprim/sulfamethoxazole) 3

Duration of Therapy

• For patients with non-severe, microbiologically undefined pneumonia, 10 days of treatment is proposed 2
• For severe pneumonia where legionella, staphylococcal, or Gram-negative enteric bacilli are suspected or confirmed, treatment should be extended to 14-21 days 2
• Newer evidence suggests patients with CAP can be treated for a minimum of 5 days if they are clinically stable 1, 4
• 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

Switching from IV to Oral Therapy

• Patients should be switched from intravenous to oral therapy when they are hemodynamically stable and improving clinically 1, 5
• Criteria for switch include:
  • Improvement in cough and dyspnea
  • Afebrile (<100°F) on two occasions 8 hours apart
  • Decreasing white blood cell count
  • Functioning gastrointestinal tract with adequate oral intake 2, 1
• Even if the patient remains febrile, switch therapy can occur if other clinical features are favorable 2

Management of Treatment Failure

• For patients who fail to improve as expected, there should be a careful review of the clinical history, examination, prescription chart, and results of all available investigations 2
• Further investigations, including a repeat chest radiograph, CRP, white cell count, and additional microbiological testing should be considered 2
• When a change in empirical antibiotic treatment is necessary:
  • For non-severe pneumonia treated with amoxicillin monotherapy, a macrolide could be substituted or added 2
  • For non-severe pneumonia on combination therapy, changing to a fluoroquinolone with effective pneumococcal coverage is an option 2
  • For severe pneumonia not responding to combination antibiotics, the addition of rifampicin may be considered 2

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
• A chest radiograph should be arranged at follow-up for patients with persistent symptoms or physical signs, or who are at higher risk of underlying malignancy (especially smokers and those over 50 years) 1