What is the recommended dose of liquid azithromycin (macrolide antibiotic) for a 30 lb (13.6 kg) boy?

Azithromycin Dosing for a 30 lb (13.6 kg) Boy

For a 30 lb (13.6 kg) boy, the recommended dose of liquid azithromycin is 10 mg/kg (136 mg) on day 1, followed by 5 mg/kg (68 mg) once daily on days 2-5 for most infections. 1

Dosing Based on Weight and Indication

Standard 5-Day Regimen

• For a 30 lb (13.6 kg) child, the FDA-approved dosing for most infections including community-acquired pneumonia is:
  • Day 1: 10 mg/kg = 136 mg (approximately 7.5 mL of 100 mg/5 mL suspension or 3.75 mL of 200 mg/5 mL suspension) 1
  • Days 2-5: 5 mg/kg = 68 mg daily (approximately 3.75 mL of 100 mg/5 mL suspension or 1.9 mL of 200 mg/5 mL suspension) 1
• Total course: 22.5 mL of 200 mg/5 mL suspension (900 mg total) 1

Alternative Regimens by Indication

• Acute Otitis Media options:

  • 5-day regimen as above 1
  • 3-day regimen: 10 mg/kg (136 mg) once daily for 3 days 1
  • Single-dose regimen: 30 mg/kg (408 mg) as a one-time dose 1

• Acute Bacterial Sinusitis:

  • 10 mg/kg (136 mg) once daily for 3 days 1

• Pharyngitis/Tonsillitis:

  • 12 mg/kg (163 mg) once daily for 5 days 1
  • This higher dose is recommended due to evidence of more recurrences with standard dosing 2

Administration Considerations

• Azithromycin suspension can be given with or without food 1
• The suspension is generally well-tolerated by children, with good palatability 3
• For the 30 lb child, use the pre-marked dosing spoon/syringe to measure the exact volume needed 1

Clinical Pharmacology Considerations

• Azithromycin achieves high tissue concentrations that exceed serum levels by up to 100-fold 4
• The drug concentrates in infection sites and maintains effective levels for several days after completing the course 4
• Once-daily administration results in sustained systemic exposure 5
• The long tissue half-life allows for shorter treatment courses compared to other antibiotics 6

Safety Considerations

• Most common adverse effects are gastrointestinal (nausea, vomiting, abdominal pain) 7
• Approximately 9% of pediatric patients experience treatment-related adverse events, typically mild to moderate 3
• Azithromycin should not be administered with aluminum- or magnesium-containing antacids as they reduce absorption 7
• Monitor for potential drug interactions with medications metabolized by cytochrome P450 enzyme system 7

Special Considerations

• For infants <6 months, azithromycin is preferred over erythromycin due to lower risk of infantile hypertrophic pyloric stenosis 7
• For pertussis treatment or prophylaxis, the 5-day regimen is recommended 7
• The 3-day and 1-day regimens have not been established as effective for community-acquired pneumonia in children 1

Azithromycin's convenient once-daily dosing and shorter treatment duration compared to other antibiotics makes it an excellent choice for pediatric infections when clinically appropriate.