Azithromycin Pediatric Dosing
Standard Dosing for Children ≥6 Months
For most pediatric infections in children 6 months and older, azithromycin should be dosed at 10 mg/kg (maximum 500 mg) on day 1, followed by 5 mg/kg once daily (maximum 250 mg/day) on days 2–5. 1
Indication-Specific Dosing (Children ≥6 Months)
- Community-acquired pneumonia (atypical pathogens): 10 mg/kg day 1, then 5 mg/kg daily days 2–5 2, 1
- Acute otitis media: Three FDA-approved regimens exist 1:
- 10 mg/kg day 1, then 5 mg/kg daily days 2–5 (5-day regimen)
- 10 mg/kg once daily for 3 days (3-day regimen)
- 30 mg/kg as a single dose (1-day regimen)
- Acute bacterial sinusitis: 10 mg/kg once daily for 3 days 1
- Pharyngitis/tonsillitis (streptococcal): 12 mg/kg once daily for 5 days (maximum 500 mg/day) 1
Intravenous Dosing (Hospitalized Children)
- Severe community-acquired pneumonia: 10 mg/kg IV on days 1 and 2, then transition to oral therapy 2, 3
Dosing for Infants <6 Months
For infants younger than 6 months, azithromycin dosing is 10 mg/kg once daily for 5 days. 4
Important Safety Consideration
- Erythromycin (not azithromycin) carries risk of infantile hypertrophic pyloric stenosis (IHPS) in infants <1 month old 4
- Azithromycin is the preferred macrolide for neonates and young infants when macrolide therapy is indicated 4
- The specific indication studied in this age group was pertussis prophylaxis and treatment 4
Weight-Based Dosing Tables
5-Day Regimen (Community-Acquired Pneumonia, Otitis Media)
| Weight | Day 1 Dose | Days 2–5 Dose | Total Course |
|---|---|---|---|
| 5 kg (11 lbs) | 2.5 mL (100 mg/5 mL) | 1.25 mL | 150 mg [1] |
| 10 kg (22 lbs) | 5 mL | 2.5 mL | 300 mg [1] |
| 20 kg (44 lbs) | 5 mL (200 mg/5 mL) | 2.5 mL | 600 mg [1] |
| 30 kg (66 lbs) | 7.5 mL | 3.75 mL | 900 mg [1] |
| 40 kg (88 lbs) | 10 mL | 5 mL | 1200 mg [1] |
| ≥50 kg (≥110 lbs) | 12.5 mL | 6.25 mL | 1500 mg [1] |
Pharyngitis/Tonsillitis (12 mg/kg × 5 days)
| Weight | Daily Dose (Days 1–5) | Total Course |
|---|---|---|
| 8 kg (18 lbs) | 2.5 mL (200 mg/5 mL) | 500 mg [1] |
| 17 kg (37 lbs) | 5 mL | 1000 mg [1] |
| 25 kg (55 lbs) | 7.5 mL | 1500 mg [1] |
| 33 kg (73 lbs) | 10 mL | 2000 mg [1] |
| 40 kg (88 lbs) | 12.5 mL | 2500 mg [1] |
Key Clinical Pearls
Administration
- Can be taken with or without food 1
- Do not co-administer with aluminum- or magnesium-containing antacids (reduces absorption) 4
Common Pitfalls
- Underdosing streptococcal pharyngitis: Using 10 mg/kg instead of the required 12 mg/kg leads to treatment failure and higher recurrence rates compared to penicillin 3, 1
- Re-dosing after vomiting: For the single 30 mg/kg dose regimen in otitis media, safety of re-dosing has not been established; in clinical trials, patients who vomited within 30 minutes were re-dosed at the same total dose 1
Tolerability
- Gastrointestinal adverse events occur in approximately 9–18% of pediatric patients, primarily diarrhea (3–6%), vomiting (2–6%), and abdominal pain (1–3%) 1, 5
- Better tolerated than amoxicillin/clavulanate (4% vs 31% treatment-related adverse events in one study) 1
- Higher doses (30 mg/kg single dose, 20 mg/kg daily) associated with more adverse effects but still generally well-tolerated 5