Azithromycin Dosing for Children
For most pediatric infections, azithromycin should be dosed at 10 mg/kg (maximum 500 mg) on day 1, followed by 5 mg/kg (maximum 250 mg) once daily on days 2-5. 1
Standard Dosing Regimens by Indication
Community-Acquired Pneumonia (Including Atypical Pathogens)
- Preferred regimen: 10 mg/kg on day 1, then 5 mg/kg once daily for days 2-5 2, 3, 1
- This 5-day course is specifically recommended for Mycoplasma pneumoniae and Chlamydophila pneumoniae infections 2, 3
- For intravenous therapy when needed: 10 mg/kg on days 1 and 2, then transition to oral 2
Acute Otitis Media
The FDA label provides three acceptable regimens 1:
- 5-day regimen: 10 mg/kg day 1, then 5 mg/kg days 2-5 (most commonly used)
- 3-day regimen: 10 mg/kg once daily for 3 days
- Single-dose regimen: 30 mg/kg as a single dose (maximum 1,500 mg)
Acute Bacterial Sinusitis
- 10 mg/kg once daily for 3 days 1
Pharyngitis/Tonsillitis (Group A Streptococcus)
- 12 mg/kg once daily for 5 days (maximum 500 mg/day) 3, 1
- Critical caveat: This higher dose (12 mg/kg vs. 10 mg/kg) is necessary because standard dosing has shown higher recurrence rates compared to penicillin 4
- Only use in children ≥2 years of age 1
Pertussis Treatment and Prophylaxis
- Infants <6 months: 10 mg/kg once daily for 5 days 3
- Children ≥6 months: 10 mg/kg day 1, then 5 mg/kg days 2-5 3
- Azithromycin is preferred over erythromycin in young infants due to better safety profile and no association with infantile hypertrophic pyloric stenosis 3
Weight-Based Dosing Tables
For the standard 5-day regimen (community-acquired pneumonia, otitis media) 1:
| Weight | Day 1 Dose | Days 2-5 Dose | Total Course |
|---|---|---|---|
| 5 kg (11 lbs) | 2.5 mL | 1.25 mL | 150 mg |
| 10 kg (22 lbs) | 5 mL | 2.5 mL | 300 mg |
| 20 kg (44 lbs) | 5 mL* | 2.5 mL* | 600 mg |
| 30 kg (66 lbs) | 7.5 mL | 3.75 mL | 900 mg |
| 40 kg (88 lbs) | 10 mL | 5 mL | 1,200 mg |
| ≥50 kg (≥110 lbs) | 12.5 mL | 6.25 mL | 1,500 mg |
*Using 200 mg/5 mL concentration 1
For pharyngitis/tonsillitis (12 mg/kg daily for 5 days) 1:
| Weight | Daily Dose | Total Course |
|---|---|---|
| 8 kg (18 lbs) | 2.5 mL | 500 mg |
| 17 kg (37 lbs) | 5 mL | 1,000 mg |
| 25 kg (55 lbs) | 7.5 mL | 1,500 mg |
| 33 kg (73 lbs) | 10 mL | 2,000 mg |
| 40 kg (88 lbs) | 12.5 mL | 2,500 mg |
Age Restrictions and Special Populations
- Minimum age: 6 months for most indications (otitis media, sinusitis, pneumonia) 1
- Pharyngitis/tonsillitis: Only approved for children ≥2 years 1
- Neonates and infants <1 month: Can use 10 mg/kg once daily for 5 days for pertussis, where benefits outweigh risks 3
- Maximum daily dose: Do not exceed adult doses (500 mg day 1,250 mg days 2-5 for standard regimen) 2, 1
Administration Considerations
- Can be taken with or without food 1
- Avoid concurrent antacids: Aluminum- or magnesium-containing antacids reduce absorption 3
- If vomiting occurs: For the single 30 mg/kg dose regimen, if vomiting occurs within 30 minutes, re-dosing at the same total dose has been studied in limited patients, though safety data are limited 1
Safety Profile
- Adverse events occur in approximately 9% of pediatric patients, predominantly mild-to-moderate gastrointestinal symptoms (diarrhea, abdominal pain, nausea, vomiting) 5, 6
- Better tolerated than amoxicillin/clavulanate and has fewer gastrointestinal effects than erythromycin 3, 5
- Treatment discontinuation due to adverse events: Only 1.3% of children 5
- Higher doses (20-30 mg/kg) are associated with more adverse effects but remain generally well-tolerated 6
- Monitor for QT prolongation when used with other QT-prolonging medications 3