Azithromycin Dosing for a 9-Year-Old Weighing 132 lbs
For a 9-year-old child weighing 132 lbs (60 kg), the appropriate azithromycin dose depends on the indication, but the standard regimen is 500 mg on day 1, followed by 250 mg once daily on days 2-5 (maximum adult dose).
Weight-Based Dosing Calculation
This child weighs 60 kg, which exceeds the typical pediatric weight thresholds in dosing guidelines. According to FDA labeling and clinical practice guidelines, doses for oral therapy should not exceed adult doses 1, 2.
For Common Indications:
Community-Acquired Pneumonia (CAP):
- Standard pediatric dosing: 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg/day on days 2-5 (maximum 250 mg/day) 1, 2
- For this 60 kg child: This would calculate to 600 mg on day 1 and 300 mg on days 2-5, but the maximum adult dose caps this at 500 mg/250 mg 2
- Give: 500 mg day 1, then 250 mg daily days 2-5
Pharyngitis/Tonsillitis:
- Pediatric dosing: 12 mg/kg once daily for 5 days 2
- For this 60 kg child: Would calculate to 720 mg daily, but cap at adult maximum of 500 mg daily for 5 days 2
- Give: 500 mg once daily for 5 days
Acute Otitis Media or Acute Bacterial Sinusitis:
- 3-day regimen: 10 mg/kg once daily for 3 days (maximum 500 mg/day) 2
- Give: 500 mg once daily for 3 days
Key Clinical Considerations
Formulation Selection
At this weight and age, tablets or capsules are appropriate rather than suspension. The child can take standard 250 mg or 500 mg tablets 2.
Important Safety Points
Drug Interactions:
- Avoid concurrent aluminum- or magnesium-containing antacids (reduces absorption) 3
- Monitor if taking medications metabolized by cytochrome P450 (digoxin, triazolam, ergot alkaloids) 3
Adverse Effects:
- Common: Abdominal discomfort, diarrhea, nausea, vomiting, headache 3, 2
- These are generally mild to moderate and rarely require discontinuation 4
- Higher doses (like the 30 mg/kg single-dose regimen) are associated with more GI adverse effects 4
Hepatic Function:
- Use with caution in patients with impaired hepatic function 3
- If ALT >40, consider dose reduction of approximately 15% based on pharmacokinetic data 5
Dosing Pitfalls to Avoid
Do not exceed adult maximum doses even when weight-based calculations suggest higher amounts 1, 2
Do not use the 30 mg/kg single-dose regimen (approved only for acute otitis media in younger children) for other indications in this age group 2, 6
Ensure appropriate indication: Azithromycin provides atypical coverage (Mycoplasma, Chlamydophila) and should not be used as monotherapy for typical bacterial pneumonia requiring beta-lactam coverage 1
Duration matters: The 5-day regimen (500/250 mg) is standard for most respiratory infections; 3-day regimens are acceptable for specific indications like sinusitis 2