What is the recommended IV antibiotic regimen for a patient with pneumonia?

IV Antibiotic Regimen for Pneumonia

For patients with pneumonia requiring IV antibiotics, the recommended regimen should be based on the type of pneumonia (community-acquired vs. hospital-acquired) and risk factors for resistant organisms.

Community-Acquired Pneumonia (CAP)

• For non-severe CAP without risk factors for MRSA or resistant pathogens, use one of the following monotherapy options:

  • Piperacillin-tazobactam 3.375 g IV every 6 hours 1
  • Cefepime 2 g IV every 8 hours 2
  • Levofloxacin 750 mg IV daily 2
  • Imipenem 500 mg IV every 6 hours 2
  • Meropenem 1 g IV every 8 hours 2

• For CAP requiring combination therapy, add a macrolide:

  • Azithromycin 500 mg IV daily for at least 2 days, followed by oral therapy to complete 7-10 days 3, 4
  • Alternatively, ceftriaxone 1-2 g IV daily plus azithromycin has shown excellent efficacy 5, 6, 4

Hospital-Acquired Pneumonia (HAP)

Not at High Risk of Mortality and No Risk Factors for MRSA:

• Use one of the following monotherapy options:
  • Piperacillin-tazobactam 4.5 g IV every 6 hours 2
  • Cefepime 2 g IV every 8 hours 2
  • Levofloxacin 750 mg IV daily 2
  • Imipenem 500 mg IV every 6 hours 2
  • Meropenem 1 g IV every 8 hours 2

Not at High Risk of Mortality but With Risk Factors for MRSA:

• Use one of the above antibiotics plus MRSA coverage:
  • Vancomycin 15 mg/kg IV every 8-12 hours (target trough 15-20 mg/mL) 2
  • OR Linezolid 600 mg IV every 12 hours 2

High Risk of Mortality or Recent IV Antibiotics:

• Use two of the following (avoid using two β-lactams):

  • Piperacillin-tazobactam 4.5 g IV every 6 hours 2
  • Cefepime or ceftazidime 2 g IV every 8 hours 2
  • Levofloxacin 750 mg IV daily or ciprofloxacin 400 mg IV every 8 hours 2
  • Imipenem 500 mg IV every 6 hours or meropenem 1 g IV every 8 hours 2
  • Amikacin 15-20 mg/kg IV daily, gentamicin 5-7 mg/kg IV daily, or tobramycin 5-7 mg/kg IV daily 2
  • Aztreonam 2 g IV every 8 hours (if severe penicillin allergy) 2

• Plus MRSA coverage:

  • Vancomycin 15 mg/kg IV every 8-12 hours (consider loading dose of 25-30 mg/kg for severe illness) 2
  • OR Linezolid 600 mg IV every 12 hours 2

Ventilator-Associated Pneumonia (VAP)

• For VAP with risk of multidrug-resistant pathogens, use:
  • One gram-positive option with MRSA activity (vancomycin or linezolid) 2
  • One β-lactam-based agent with antipseudomonal activity 2
  • One non-β-lactam agent with antipseudomonal activity 2

Special Considerations

• For nosocomial pneumonia with suspected Pseudomonas aeruginosa:

  • Piperacillin-tazobactam 4.5 g IV every 6 hours plus an aminoglycoside 1
  • Treatment duration: 7-14 days 1

• For patients with renal impairment:

  • Adjust dosing based on creatinine clearance according to specific antibiotic guidelines 1

• Risk factors for multidrug-resistant pathogens include:

  • Prior IV antibiotic use within 90 days 2
  • Septic shock 2
  • ARDS preceding pneumonia 2
  • Five or more days of hospitalization prior to pneumonia onset 2
  • Acute renal replacement therapy 2

Duration of Therapy

• Community-acquired pneumonia: 7-10 days 3, 4
• Hospital-acquired pneumonia: 7-14 days 1
• Consider switching to oral therapy when the patient is clinically stable and can tolerate oral intake 2, 3

Common Pitfalls to Avoid

• Underdosing in severe pneumonia: For nosocomial pneumonia, use higher doses (e.g., piperacillin-tazobactam 4.5 g rather than 3.375 g) 1
• Inadequate coverage for Pseudomonas: Add an aminoglycoside when P. aeruginosa is suspected or confirmed 1
• Failure to adjust for renal impairment: Dose adjustments are critical for patients with CrCl ≤ 40 mL/min 1
• Inappropriate monotherapy: For patients with risk factors for mortality or resistant pathogens, combination therapy is recommended 2
• Excessive use of broad-spectrum antibiotics: De-escalate therapy once culture results are available to prevent resistance development 2