What respiratory diagnoses can I prescribe a Z-Pak (azithromycin) for?

Appropriate Respiratory Diagnoses for Z-Pak (Azithromycin) Prescription

Azithromycin (Z-Pak) should only be prescribed for specific respiratory diagnoses where it has proven efficacy and FDA approval, including acute bacterial sinusitis, community-acquired pneumonia in appropriate patients, and acute exacerbations of chronic obstructive pulmonary disease. 1

FDA-Approved Respiratory Indications

• Acute bacterial exacerbations of chronic obstructive pulmonary disease (AECB) caused by Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae 1
• Acute bacterial sinusitis due to Haemophilus influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae 1
• Community-acquired pneumonia (CAP) due to Chlamydophila pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, or Streptococcus pneumoniae in patients appropriate for oral therapy 1, 2

Important Contraindications and Limitations

• Not appropriate for pneumonia patients who are judged inappropriate for oral therapy due to moderate to severe illness or risk factors such as:
  • Patients with cystic fibrosis
  • Patients with nosocomially acquired infections
  • Patients with known or suspected bacteremia
  • Patients requiring hospitalization
  • Elderly or debilitated patients
  • Patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia) 1

Specific Guidance by Condition

Acute Bacterial Sinusitis

• Appropriate for subacute forms of purulent maxillary sinusitis, especially after symptomatic treatment failure 2
• Typical treatment duration is 5 days 2
• Consider azithromycin extended release as a single 2.0g dose, which has shown noninferiority to 10-day regimens of other antibiotics 3

Community-Acquired Pneumonia

• For outpatients with no cardiopulmonary disease and no risk factors for drug-resistant S. pneumoniae (DRSP), an advanced generation macrolide like azithromycin is appropriate first-line therapy 2
• Not recommended for patients requiring hospitalization 1
• For pediatric patients, azithromycin has demonstrated efficacy with fewer side effects than comparator drugs 4

Acute Exacerbations of Chronic Bronchitis

• Indicated when at least two of the Anthonisen triad criteria are present (increased volume and purulence of expectoration, increased dyspnea) 2
• A 3-day regimen of azithromycin has shown equivalent efficacy to 10-day regimens of other antibiotics 5, 6
• In COPD, azithromycin may be considered for exacerbation prevention in former smokers ≥65 years with moderate to very severe airflow obstruction on an otherwise optimized regimen 2

Important Considerations and Cautions

• Resistance concerns: The prevalence of macrolide-resistant S. pneumoniae has been increasing, with 25-50% of strains showing resistance 2
• QT prolongation risk: Consider the risk of QT prolongation which can be fatal in at-risk groups, including patients with:
  • Known prolongation of the QT interval
  • History of torsades de pointes
  • Congenital long QT syndrome
  • Bradyarrhythmias or uncompensated heart failure
  • Concurrent use of drugs known to prolong the QT interval 1
• Selective pressure: Azithromycin's long half-life may create a "window" for potential selection of resistant organisms 2
• Inappropriate use: Azithromycin should not be prescribed for:
  • Acute uncomplicated bronchitis (viral etiology) 2
  • Viral upper respiratory tract infections 2
  • Common cold or congestive rhinosinusitis 2

Dosing Recommendations

• Acute bacterial sinusitis: 500mg once daily for 3 days 3
• Community-acquired pneumonia: 500mg on day 1, then 250mg daily for 4 days 1
• Acute exacerbations of COPD: 500mg once daily for 3 days 5

Remember that appropriate antibiotic stewardship requires confirming bacterial etiology when possible and using the narrowest spectrum antibiotic effective for the condition to minimize development of resistance.