What is the recommended dose of azithromycin (macrolide antibiotic) syrup for a 20kg child?

Azithromycin Syrup Dosing for a 20kg Child

For a 20kg child, the recommended dose of azithromycin syrup is 10 mg/kg (200 mg) on day 1, followed by 5 mg/kg (100 mg) daily for days 2-5. 1, 2

Standard Dosing Regimens

• For most infections including community-acquired pneumonia, the FDA-approved dosage is 10 mg/kg on day 1, followed by 5 mg/kg once daily on days 2-5 2
• For a 20kg child, this translates to:
  • Day 1: 200 mg (10 mg/kg × 20 kg)
  • Days 2-5: 100 mg (5 mg/kg × 20 kg) 1, 2
• According to the FDA label, this would be administered as 5 mL of the 200 mg/5 mL suspension on day 1, followed by 2.5 mL on days 2-5 2

Alternative Dosing Options Based on Indication

• Acute Otitis Media: Three options are available 2:

  • 5-day regimen: 10 mg/kg (200 mg) on day 1, followed by 5 mg/kg (100 mg) daily for days 2-5
  • 3-day regimen: 10 mg/kg (200 mg) daily for 3 days
  • 1-day regimen: 30 mg/kg (600 mg) as a single dose 2

• Acute Bacterial Sinusitis: 10 mg/kg (200 mg) once daily for 3 days 2

• Pharyngitis/Tonsillitis: A higher dose of 12 mg/kg (240 mg) once daily for 5 days is recommended 2, 3

  • This higher dose is necessary as studies have shown better GABHS eradication with a total dose of 60 mg/kg 3

Administration Guidelines

• Azithromycin suspension can be taken with or without food 2
• For the 20kg child, use the 200 mg/5 mL concentration for more accurate dosing 2
• Ensure the suspension is well-shaken before each use 1
• Do not administer with aluminum- or magnesium-containing antacids as they reduce absorption 1

Safety Considerations

• Azithromycin is generally well-tolerated in children with approximately 9% experiencing treatment-related adverse events, most commonly gastrointestinal complaints 4
• The standard 5-day regimen has fewer side effects than the higher-dose shorter regimens (30 mg/kg single dose or 20 mg/kg/day for 3 days) 4
• Monitor for potential drug interactions, particularly with medications that prolong the QT interval 1

Clinical Pearls

• Azithromycin's long tissue half-life allows for once-daily dosing and shorter treatment courses compared to other antibiotics 5, 6
• Measurable levels remain in the body for up to 72 hours after the last dose, providing continued antimicrobial activity 6
• For pertussis treatment in children, the CDC recommends the same 5-day regimen (10 mg/kg on day 1, followed by 5 mg/kg for 4 more days) 1, 7

Remember that while alternative dosing regimens exist for specific indications, the standard 5-day regimen (10 mg/kg on day 1, followed by 5 mg/kg on days 2-5) remains the most commonly recommended approach for most pediatric infections 1, 2.