Azithromycin Dosing for a 10-Year-Old, 62 kg Patient with CAP
For a 10-year-old patient weighing 62 kg with community-acquired pneumonia, administer azithromycin 500 mg on day 1, followed by 250 mg once daily on days 2-5. 1, 2, 3
Weight-Based Dosing Considerations
This patient exceeds the weight threshold where standard pediatric weight-based dosing (10 mg/kg day 1, then 5 mg/kg days 2-5) would reach adult maximum doses:
- Standard pediatric calculation: 10 mg/kg × 62 kg = 620 mg (exceeds adult maximum of 500 mg) 1, 2
- Correct approach: Cap at adult maximum doses regardless of weight-based calculation 2, 3
- Final dosing: 500 mg day 1, then 250 mg daily for days 2-5 1, 2, 3
Clinical Context for Azithromycin Use
Azithromycin is specifically indicated for atypical pneumonia caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Chlamydia trachomatis in children ≥5 years old 1:
- Not first-line for typical bacterial CAP: Amoxicillin (90 mg/kg/day in 2 doses, maximum 4 g/day) remains the preferred agent for Streptococcus pneumoniae and Haemophilus influenzae 1, 3
- When to use azithromycin alone: Clinical presentation suggests atypical pathogen (gradual onset, prominent cough, minimal fever, interstitial infiltrates on chest X-ray) 1
- Combination therapy: For children ≥5 years with CAP where bacterial vs. atypical etiology cannot be distinguished clinically, a macrolide can be added to a β-lactam antibiotic 1
Administration Details
- Can be taken with or without food 4
- Oral formulation preferred: Transition from IV to oral therapy as soon as clinically feasible 1, 2
- Avoid concurrent antacids: Do not administer simultaneously with aluminum- or magnesium-containing antacids, as they reduce absorption 2, 3
Common Pitfall to Avoid
Do not exceed adult maximum doses even when weight-based calculations suggest higher doses 2, 3. For adolescents and larger children, oral azithromycin doses should never exceed 500 mg on day 1 and 250 mg daily for the 5-day respiratory regimen, regardless of weight 2.