Treatment for Community-Acquired Pneumonia (CAP)
CAP treatment refers to the antibiotic therapy regimen used for community-acquired pneumonia, which typically consists of a beta-lactam plus a macrolide or a respiratory fluoroquinolone, with specific regimens varying based on patient setting and risk factors. 1
Treatment Algorithm Based on Patient Setting
Outpatient Treatment
- First-line: Amoxicillin 1g three times daily (3g/day) 2
- For penicillin allergy: Respiratory fluoroquinolone (moxifloxacin or levofloxacin 750mg/day) 1
- Avoid: Macrolide monotherapy due to increasing pneumococcal resistance 1
Non-ICU Inpatient Treatment
- First-line: IV beta-lactam (ceftriaxone, cefotaxime, or ampicillin-sulbactam) plus a macrolide 1
- Alternative to macrolide: Doxycycline 1
- For penicillin allergy: IV respiratory fluoroquinolone (moxifloxacin or levofloxacin 750mg/day) 1
ICU Treatment
- First-line: IV beta-lactam (ceftriaxone, cefotaxime, or ampicillin-sulbactam) plus either IV azithromycin or IV respiratory fluoroquinolone 1
- For penicillin allergy: Aztreonam plus IV respiratory fluoroquinolone 1
Special Considerations
Pseudomonas Risk Factors
If risk factors for Pseudomonas infection are present:
- Preferred regimen: Antipseudomonal beta-lactam (piperacillin-tazobactam, cefepime, imipenem, or meropenem) plus either ciprofloxacin or levofloxacin (750mg) 1
- Alternative regimens:
- Antipseudomonal beta-lactam + aminoglycoside + azithromycin
- Antipseudomonal beta-lactam + aminoglycoside + antipneumococcal fluoroquinolone 1
- For penicillin allergy: Substitute aztreonam for beta-lactam 1
MRSA Risk Factors
If risk factors for Staphylococcus aureus infection, including CA-MRSA:
- Add vancomycin (possibly with clindamycin) or linezolid to the regimen 1
Treatment Duration and Monitoring
- Standard duration: 5-7 days 1, 2
- Criteria for discontinuation: Afebrile for 48-72 hours and no more than 1 CAP-associated sign of clinical instability 1
- Switch from IV to oral: When patient is hemodynamically stable, improving clinically, able to swallow and tolerate oral medications, and has intact gastrointestinal function 1
Important Clinical Pearls
- Obtain sputum and blood cultures before starting antibiotics to allow for pathogen-directed therapy 1
- Consider stopping antibiotics after 48 hours if cultures and urinary antigen tests show no bacterial pathogens 1
- Fluoroquinolones should be used with caution in patients with suspected tuberculosis due to their activity against M. tuberculosis 1
- Patients receiving macrolide prophylaxis for MAC should never receive macrolide monotherapy for empiric treatment of bacterial pneumonia 1
- Clinical response should be assessed within 48-72 hours of initiating therapy 2
Treatment Pitfalls to Avoid
- Avoid macrolide monotherapy due to increasing pneumococcal resistance rates 1
- Avoid trimethoprim-sulfamethoxazole due to inadequate activity against S. pneumoniae 2
- Avoid first-generation cephalosporins due to inadequate activity 2
- Avoid unnecessary broad-spectrum antibiotics to prevent antimicrobial resistance 1, 3
- Avoid delaying antibiotics in severe cases, as early appropriate therapy is essential for improved outcomes 3
By following this evidence-based approach to CAP treatment, clinicians can optimize patient outcomes while practicing good antimicrobial stewardship.