Azithromycin Prescription for Atypical Pneumonia
For healthy outpatients with atypical pneumonia, prescribe azithromycin 500 mg on day 1, followed by 250 mg once daily on days 2-5 for a total 5-day course. 1, 2, 3
Complete Prescription Template
Medication: Azithromycin (Zithromax)
Indication: Community-acquired atypical pneumonia
Dose: 500 mg PO on Day 1, then 250 mg PO once daily on Days 2-5
Total Duration: 5 days
Quantity: 6 tablets (one 500 mg tablet + five 250 mg tablets)
Refills: 0
Instructions: Take 500 mg by mouth on the first day, then take 250 mg by mouth once daily for the next 4 days. May be taken with or without food. 3
Critical Patient Selection Criteria
When Azithromycin Monotherapy is CONTRAINDICATED:
Do NOT use azithromycin alone if the patient has ANY of the following: 1, 2
- Age >65 years
- COPD or other chronic lung disease
- Diabetes mellitus
- Heart failure or chronic heart disease
- Renal failure or chronic kidney disease
- Liver disease
- Malignancy
- Alcoholism
- Asplenia
- Immunosuppression
- Recent antibiotic use within past 3 months
- Hospitalization required
- Local macrolide resistance ≥25%
For Patients with Risk Factors - Mandatory Combination Therapy:
If any risk factors above are present, prescribe: 1, 2
- Amoxicillin 1 g PO three times daily (or amoxicillin-clavulanate 2000 mg/125 mg twice daily)
- PLUS azithromycin 500 mg on day 1, then 250 mg daily on days 2-5
Hospitalized Patients
Azithromycin monotherapy is absolutely contraindicated in hospitalized patients. 1, 2
- IV azithromycin 500 mg daily
- PLUS a β-lactam (ceftriaxone 1-2 g IV daily, cefotaxime 1-2 g IV every 8 hours, or ampicillin-sulbactam 1.5-3 g IV every 6 hours)
- Continue IV therapy for 2-5 days, then transition to oral azithromycin 500 mg on day 1, then 250 mg daily to complete 7-10 days total 1
Specific Pathogen Considerations
Mycoplasma pneumoniae:
- Standard 5-day azithromycin regimen is effective 1, 4, 5
- Be aware that macrolide resistance exceeds 95% in some Asian regions, particularly China 1
- Alternative agents if resistance suspected: levofloxacin 750 mg daily or doxycycline 100 mg twice daily 1
Chlamydophila pneumoniae:
- Azithromycin is the preferred agent with 80% nasopharyngeal eradication rates 1
- 5-day course is adequate 1
Legionella species:
- Azithromycin is effective but consider 7-10 day course (not the standard 5-day) 1
- For severe Legionella or immunocompromised patients, extend to 21 days 1
- Respiratory fluoroquinolones (levofloxacin 750 mg daily) may provide faster defervescence 1
Pediatric Dosing (≥6 months)
Standard 5-day regimen: 2, 3, 6
- Day 1: 10 mg/kg PO (maximum 500 mg)
- Days 2-5: 5 mg/kg PO once daily (maximum 250 mg/day)
- Total course: 1.5 grams over 5 days
Alternative 3-day regimen for otitis media/sinusitis: 3
- 10 mg/kg PO once daily for 3 days
Single-dose regimen for otitis media: 3
- 30 mg/kg PO as single dose (maximum 1500 mg)
Safety Monitoring
Before Prescribing:
- Obtain baseline ECG in patients with cardiac risk factors 2
- Contraindicate if QTc >450 ms (men) or >470 ms (women) 2
- Avoid in patients with history of QT prolongation, arrhythmias, or concurrent QT-prolonging medications 2
Expected Clinical Response:
- Patients should demonstrate clinical improvement within 48-72 hours 2, 4, 5
- Most patients become afebrile within 48 hours of treatment initiation 4
- If no improvement by 72 hours, consider treatment failure and reassess diagnosis 2
Common Pitfalls to Avoid
Using azithromycin monotherapy in patients who received antibiotics in the past 3 months - this increases risk of resistant organisms 2
Prescribing azithromycin alone in areas with macrolide resistance ≥25% - use combination therapy or fluoroquinolone instead 1, 2
Using azithromycin as monotherapy in hospitalized patients - always combine with β-lactam 1, 2
Failing to screen for cardiac risk factors - QT prolongation can cause fatal arrhythmias 2
Assuming all "atypical pneumonia" is mild - Legionella can be severe and may require longer treatment or fluoroquinolone therapy 1
Alternative Regimens
If azithromycin is contraindicated or ineffective: 1
- Doxycycline 100 mg PO twice daily for 7-10 days (avoid in children <8 years)
- Levofloxacin 750 mg PO once daily for 5 days
- Moxifloxacin 400 mg PO once daily for 5 days
For severe disease or ICU patients: 1
- β-lactam (ceftriaxone or cefotaxime) PLUS azithromycin 500 mg IV daily, OR
- β-lactam PLUS respiratory fluoroquinolone (levofloxacin 750 mg IV daily)