Recommended Treatment for Pneumonia
Treatment depends critically on the setting and severity of illness: outpatient community-acquired pneumonia (CAP), hospitalized non-ICU CAP, severe ICU-requiring CAP, or hospital-acquired/ventilator-associated pneumonia (HAP/VAP).
Outpatient Community-Acquired Pneumonia
For previously healthy outpatients without risk factors for drug-resistant pathogens, start with a macrolide (azithromycin or clarithromycin preferred over erythromycin) or doxycycline as monotherapy. 1
- Oral therapy is appropriate from the beginning for ambulatory pneumonia 2
- Treatment duration should be 7 days for uncomplicated cases 3, 1
- For patients with comorbidities or recent antibiotic exposure, consider combination therapy with amoxicillin plus a macrolide 1
Hospitalized Non-ICU Pneumonia (Moderate Severity)
Combined therapy with a beta-lactam antibiotic plus a macrolide is the preferred regimen for hospitalized patients with moderate-severity CAP. 2, 3, 1
Specific Regimens:
- Amoxicillin (high-dose to cover drug-resistant Streptococcus pneumoniae) plus azithromycin or clarithromycin 3, 1
- Alternative: Respiratory fluoroquinolone monotherapy (levofloxacin 750 mg daily or moxifloxacin), though fluoroquinolones should be avoided in pregnancy unless benefits outweigh risks 2, 3
Route and Duration:
- Intravenous antibiotics may be initiated, but switch to oral therapy once clinical improvement occurs and temperature normalizes for 24 hours 3, 1
- Treatment duration: 7-8 days for responding patients 2, 1
- Patients do not need to remain hospitalized after switching to oral therapy 2
Important Caveat:
- Avoid tigecycline due to FDA boxed warning regarding increased all-cause mortality; infectious disease consultation recommended if considering its use 2
Severe ICU-Requiring Pneumonia
For severe CAP requiring ICU admission, immediate parenteral therapy with a non-antipseudomonal third-generation cephalosporin (or beta-lactam/beta-lactamase inhibitor) plus a macrolide OR a respiratory fluoroquinolone (levofloxacin 750 mg daily or moxifloxacin) is recommended. 2, 3
Without Pseudomonas Risk Factors:
- Ceftriaxone or cefotaxime PLUS azithromycin 2
- Alternative: Moxifloxacin or levofloxacin monotherapy (± non-antipseudomonal cephalosporin) 2
With Pseudomonas Risk Factors:
Use an antipseudomonal beta-lactam (piperacillin-tazobactam 4.5g IV q6h, cefepime 2g IV q8h, or meropenem 1g IV q8h) PLUS either ciprofloxacin OR a macrolide plus an aminoglycoside (gentamicin, tobramycin, or amikacin). 2
- Piperacillin-tazobactam is FDA-approved for nosocomial pneumonia and community-acquired pneumonia 4
- Treatment duration: 10 days for microbiologically undefined severe pneumonia 3
- Meropenem can be dosed up to 6g daily (3 × 2g in 3-hour infusions) for severe cases 2
Critical Note:
- Ceftazidime must be combined with penicillin G for adequate S. pneumoniae coverage 2
Hospital-Acquired Pneumonia (HAP) and Ventilator-Associated Pneumonia (VAP)
Low Risk of Multidrug-Resistant Organisms (MDROs):
Monotherapy with piperacillin-tazobactam 4.5g IV q6h, cefepime 2g IV q8h, meropenem 1g IV q8h, or a respiratory fluoroquinolone (levofloxacin 750 mg IV daily) is appropriate. 2, 1, 4
High Risk of MDROs or Unstable Hemodynamics:
Combination therapy is mandatory: an antipseudomonal beta-lactam PLUS either an aminoglycoside (gentamicin 5-7 mg/kg IV daily or amikacin 15-20 mg/kg IV daily) OR ciprofloxacin 400 mg IV q8h. 2
MRSA Coverage:
Add vancomycin 25-30 mg/kg IV q8-12h, teicoplanin 6-12 mg/kg IV (high-dose 12 mg/kg for severe disease), or linezolid 600 mg IV q12h when MRSA risk is present. 2
Duration:
- 7 days is appropriate for patients who respond clinically 1
- Longer durations only for persistent signs of active infection 1
Risk Factors for MDROs:
- Septic shock at HAP/VAP onset 2
- ARDS preceding HAP/VAP 2
- Acute renal replacement therapy prior to onset 2
- Previous MDRO colonization 2
- Structural lung diseases (bronchiectasis) 2
Special Populations: Aspiration Pneumonia
Hospital Ward (Admitted from Home):
ICU or Nursing Home Origin:
- Clindamycin plus cephalosporin 2
Treatment Failure Management
If patients fail to improve within 48-72 hours, conduct a careful clinical review including examination, prescription verification, and repeat investigations (chest radiograph, CRP, white cell count, additional microbiological specimens). 3, 1
- For patients on amoxicillin monotherapy who fail, add or substitute a macrolide 3
- Consider empirical treatment change if no improvement 3
- De-escalate antibiotics based on culture results once available 1
Key Pitfalls to Avoid
- Do not use azithromycin monotherapy in regions with high S. pneumoniae resistance (e.g., Taiwan reports low susceptibility) 2
- Avoid fluoroquinolones in pregnancy unless absolutely necessary 3
- Monitor for neuromuscular excitability or seizures with high-dose penicillins, especially in renal impairment 4
- Piperacillin-tazobactam and aminoglycosides must be reconstituted and administered separately, though Y-site co-administration is permissible under specific conditions 4
- Watch for rhabdomyolysis with piperacillin-tazobactam; discontinue if signs develop 4
Biomarker-Guided Therapy
Procalcitonin (PCT) may guide shorter treatment duration in responding patients. 2