Azithromycin Dosing for a 2-Year-Old Weighing 27 Pounds
For a 2-year-old child weighing 27 pounds (12.3 kg), the recommended dose of azithromycin 200mg/5mL suspension is 6.25 mL (250 mg) once daily for 5 days for most respiratory infections, or 3.75 mL (150 mg) once daily for 5 days for pharyngitis/tonsillitis. 1
Weight-Based Dosing Calculation
27 pounds = 12.3 kg
For community-acquired pneumonia, acute otitis media, or acute bacterial sinusitis: The standard regimen is 10 mg/kg on day 1, followed by 5 mg/kg daily on days 2-5 2, 1
- Day 1 dose: 10 mg/kg × 12.3 kg = 123 mg (approximately 3 mL of 200mg/5mL suspension)
- Days 2-5 dose: 5 mg/kg × 12.3 kg = 61.5 mg (approximately 1.5 mL of 200mg/5mL suspension)
For pharyngitis/tonsillitis (second-line therapy): The dose is 12 mg/kg once daily for 5 days 1
- Daily dose: 12 mg/kg × 12.3 kg = 148 mg (approximately 3.75 mL of 200mg/5mL suspension) for all 5 days
Practical Dosing from FDA Label
According to the FDA-approved dosing table for children weighing 10 kg (22 lbs), using the 200mg/5mL suspension 1:
- For otitis media/pneumonia (5-day regimen): 2.5 mL on day 1, then 1.25 mL on days 2-5
- For pharyngitis/tonsillitis: The child falls between the 8 kg and 17 kg dosing brackets, requiring approximately 3.75 mL daily for 5 days
Clinical Context and Indication-Specific Considerations
- Azithromycin is NOT first-line therapy for typical bacterial pneumonia caused by Streptococcus pneumoniae or Haemophilus influenzae—amoxicillin remains the preferred agent 2
- Azithromycin is specifically indicated for atypical pneumonia caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Chlamydia trachomatis 2, 3
- For streptococcal pharyngitis, azithromycin is second-line therapy only; penicillin or amoxicillin remain first-line 4, 2
- The higher dose of 12 mg/kg daily for pharyngitis is necessary due to high recurrence rates with standard dosing 2
Administration Guidelines
- Azithromycin can be taken with or without food 1
- The suspension should be shaken well before each use
- Complete the full course even if symptoms improve 5
- Children should show clinical improvement within 48-72 hours; if not, reevaluation is necessary 2, 5
Important Safety Considerations
- Avoid concurrent administration with aluminum- or magnesium-containing antacids, as they reduce absorption 2
- Monitor for gastrointestinal side effects (abdominal discomfort, diarrhea, nausea), which are generally mild 2, 6
- Azithromycin has fewer gastrointestinal side effects compared to erythromycin 2, 6
- The drug is generally well tolerated in pediatric patients, with adverse events being mostly mild to moderate 6
Common Pitfalls to Avoid
- Do not use azithromycin as first-line empiric therapy for community-acquired pneumonia without considering typical bacterial pathogens that require beta-lactam coverage 2
- Do not underdose pharyngitis/tonsillitis—the 12 mg/kg daily regimen (not the standard 10 mg/kg then 5 mg/kg regimen) is required to prevent recurrence 2
- Ensure accurate weight-based dosing rather than age-based dosing, as pediatric dosing is primarily weight-dependent 1