What is the recommended dose of azithromycin (Zithromax) for a 2-year-old child weighing 33.8 pounds with a Mycoplasma infection using the 200mg/5mL suspension?

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Azithromycin Dosing for a 2-Year-Old with Mycoplasma Infection

For a 2-year-old child weighing 33.8 pounds (15.3 kg) with a Mycoplasma infection, the recommended dose of azithromycin 200mg/5mL suspension is 10 mg/kg (153 mg) on day 1, followed by 5 mg/kg (76.5 mg) daily for days 2-5.

Dosage Calculation

Based on the FDA-approved dosing guidelines for azithromycin in pediatric patients with community-acquired pneumonia:

  • Weight: 33.8 pounds = 15.3 kg
  • Day 1 dose: 10 mg/kg = 153 mg (approximately 3.8 mL of 200mg/5mL suspension)
  • Days 2-5 dose: 5 mg/kg = 76.5 mg (approximately 1.9 mL of 200mg/5mL suspension)

Administration Guidelines

  • Azithromycin suspension can be given with or without food 1
  • Food may improve gastrointestinal tolerability 2
  • The full 5-day course should be completed even if symptoms improve before completion

Evidence-Based Rationale

The American Academy of Pediatrics and the Infectious Diseases Society of America recommend azithromycin for treatment of atypical pneumonia caused by Mycoplasma, particularly in children 2. For community-acquired pneumonia in children, the recommended dosage is 10 mg/kg on day 1 followed by 5 mg/kg on days 2-5 1.

This dosing regimen is supported by the FDA drug label which specifically states for pediatric patients with community-acquired pneumonia: "10 mg/kg as a single dose on the first day followed by 5 mg/kg on Days 2 through 5" 1.

Monitoring and Follow-up

  • Clinical improvement should be assessed within 48-72 hours of starting therapy 3
  • If no improvement or worsening occurs within this timeframe, reevaluation is necessary 3
  • Common side effects to monitor include gastrointestinal symptoms (diarrhea, nausea, abdominal pain)

Important Considerations

  • The full 5-day course should be completed to ensure eradication of the infection and prevent development of resistance
  • If the child vomits shortly after administration, consult a healthcare provider about re-dosing
  • Azithromycin has better activity against Mycoplasma pneumoniae compared to other antibiotics like doxycycline in young children

Practical Administration Tips

  • Use a calibrated medication syringe or dosing spoon for accurate measurement
  • Shake the suspension well before each use
  • Store the suspension as directed on the package (typically at room temperature)
  • Discard any unused medication after the treatment course is completed

Remember that clinical improvement should be evident within 48-72 hours of starting appropriate therapy. If the child's condition deteriorates or shows no improvement within this timeframe, further investigation should be performed.

References

Guideline

Community-Acquired Pneumonia Treatment in Children

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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