How should I treat a patient with a penicillin allergy who has pneumonia (PNA)?

From the Guidelines

For a patient with pneumonia (PNA) and a penicillin allergy, I recommend using a respiratory fluoroquinolone and aztreonam as first-line treatment, as suggested by the Infectious Diseases Society of America/American Thoracic Society consensus guidelines 1. This approach is based on the strong recommendation from the guidelines, which prioritize the use of a respiratory fluoroquinolone and aztreonam for penicillin-allergic patients. The guidelines suggest that this combination is effective for treating community-acquired pneumonia, including cases where Pseudomonas infection is suspected. Some key points to consider when treating a patient with a penicillin allergy include:

• Clarifying the nature of the penicillin allergy to determine the best course of treatment
• Avoiding the use of beta-lactams in patients with true IgE-mediated allergies
• Considering alternative antibiotics such as macrolides or doxycycline for less severe cases
• Using a non-beta-lactam combination for more severe cases
• Monitoring the patient's clinical response to adjust the treatment duration, typically 5-7 days for community-acquired pneumonia. The use of a respiratory fluoroquinolone and aztreonam is supported by the guidelines, which provide level I evidence for the use of fluoroquinolones in this setting 1. This combination is effective against a broad range of respiratory pathogens, including those that are commonly associated with community-acquired pneumonia.

From the FDA Drug Label

In the treatment of pneumonia, azithromycin has only been shown to be safe and effective in the treatment of community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae or Streptococcus pneumoniae in patients appropriate for oral therapy For a patient with a penicillin allergy, azithromycin can be considered as a treatment option for community-acquired pneumonia (CAP) caused by susceptible organisms such as Chlamydia pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, or Streptococcus pneumoniae 2.

• Key considerations:
  • The patient should be appropriate for oral therapy
  • The patient should not have any of the following: cystic fibrosis, nosocomially acquired infections, known or suspected bacteremia, require hospitalization, elderly or debilitated, or significant underlying health problems
• Alternatively, levofloxacin can also be considered as a treatment option for CAP, including nosocomial pneumonia, as it has been shown to be effective in clinical trials 3.
  • Key considerations:
    • The patient's infection should be caused by susceptible organisms
    • The patient's renal function should be taken into account when determining the dosage of levofloxacin

From the Research

Treatment Options for Pneumonia in Patients with Penicillin Allergy

• For patients with a penicillin allergy, alternative antibiotics such as fluoroquinolones can be used to treat pneumonia, as they are active against > 98% of Streptococcus pneumoniae, including penicillin-resistant strains 4.
• The respiratory fluoroquinolones (levofloxacin, gatifloxacin, moxifloxacin, and gemifloxacin) are excellent antibiotics due to high levels of susceptibility among gram-negative, gram-positive, and atypical pathogens 4.
• Monotherapy with a "respiratory quinolone" (i.e., levofloxacin, gatifloxacin, moxifloxacin, or gemifloxacin) is considered optimal first-line therapy for patients hospitalized with community-acquired pneumonia, including those with penicillin allergy 5.

Considerations for Antibiotic Use in Patients with Penicillin Allergy

• Patients with a documented penicillin and/or cephalosporin (P/C) allergy are less likely to receive recommended beta-lactam antibiotic use and more likely to receive alternative antibiotics such as carbapenems and fluoroquinolones 6.
• Proactive evaluation and delabeling of penicillin allergies can improve optimal antibiotic therapy for patients with pneumonia and a documented P/C allergy 7.
• A variety of penicillin delabeling strategies can be used in both the outpatient and inpatient settings, including direct penicillin challenge in patients at low risk 7.

Comparison of Antibiotic Regimens

• Azithromycin plus β-lactam and levofloxacin plus β-lactam have been compared in the treatment of severe community-acquired pneumonia, with no significant differences in 28-day mortality and in-hospital mortality found between the two regimens 8.
• High-dose, short-course therapy regimens with levofloxacin, azithromycin, or telithromycin may offer improved treatment due to higher drug concentrations, more rapid killing, increased adherence, and the potential to reduce development of resistance 4.