What is the appropriate azithromycin dose for a 6-year-old boy weighing 48 pounds?

Azithromycin Dosing for a 6-Year-Old, 48-Pound Child

For a 6-year-old weighing 48 pounds (21.8 kg), the appropriate azithromycin dose is 200 mg once daily, based on weight-band dosing guidelines. 1

Weight Conversion and Dosing Calculation

• 48 pounds = 21.8 kg 1
• This weight falls into the 15-25 kg weight band, which corresponds to 200 mg once daily 1
• This dosing applies to the standard 5-day regimen for respiratory tract infections 1

Indication-Specific Dosing Regimens

The exact dosing schedule depends on the clinical indication:

For Community-Acquired Pneumonia or Atypical Pneumonia

• Day 1: 10 mg/kg (approximately 220 mg, rounded to 200 mg practically) 1, 2
• Days 2-5: 5 mg/kg (approximately 110 mg, rounded to 100 mg practically) 1, 2
• This 5-day regimen is recommended by the Infectious Diseases Society of America and American Academy of Pediatrics for atypical pathogens including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia trachomatis 1, 3

For Acute Otitis Media

• Option 1 (5-day regimen): 10 mg/kg Day 1, then 5 mg/kg Days 2-5 2
• Option 2 (3-day regimen): 10 mg/kg once daily for 3 days 2
• Option 3 (single dose): 30 mg/kg as a single dose (approximately 650 mg) 2

For Streptococcal Pharyngitis/Tonsillitis

• 12 mg/kg once daily for 5 days (approximately 260 mg daily) 1, 2
• Note: Azithromycin is second-line therapy only for strep throat; penicillin or amoxicillin remains first-line 1
• The higher 12 mg/kg dose is necessary due to high recurrence rates with standard 10 mg/kg dosing 1

Practical Administration Guidelines

• Azithromycin oral suspension can be taken with or without food 2
• Do not administer simultaneously with aluminum- or magnesium-containing antacids—separate by at least 2 hours, as antacids reduce drug absorption 1, 2
• The pediatric oral suspension formulation should be reconstituted with water before administration 1

Expected Clinical Response and Monitoring

• Children on adequate azithromycin therapy should demonstrate clinical improvement within 48-72 hours 1
• If the patient deteriorates or shows no improvement within this timeframe, further investigation is warranted, including assessment for complications such as parapneumonic effusion 1

Important Clinical Caveats

• Azithromycin is NOT first-line for typical bacterial pneumonia caused by Streptococcus pneumoniae or Haemophilus influenzae—amoxicillin remains the preferred agent for these pathogens 1
• For streptococcal pharyngitis, penicillin or amoxicillin should be used first-line, with azithromycin reserved for penicillin-allergic patients 1, 3
• Common adverse effects include gastrointestinal disturbances (abdominal discomfort, diarrhea, nausea, vomiting), which are generally mild to moderate 1, 4
• Azithromycin has fewer gastrointestinal side effects compared to erythromycin 1, 5

Alternative Macrolides for Penicillin-Allergic Patients

If azithromycin is contraindicated or unavailable:

• Clarithromycin: 15 mg/kg/day divided into 2 doses 3
• Erythromycin: 40 mg/kg/day divided into 4 doses 3
• Clarithromycin may be preferred due to better tolerability and twice-daily dosing 3