What is the appropriate dosage of Azithromycin (azithro) for a 6-year-old child weighing 50 pounds with a Mycoplasma infection?

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Last updated: April 22, 2025View editorial policy

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From the Guidelines

For a 50-pound (22.7 kg) 6-year-old child with Mycoplasma infection, the recommended azithromycin dosage is 10 mg/kg on day 1 (maximum 500 mg), followed by 5 mg/kg on days 2-5 (maximum 250 mg daily). This dosage is based on the guidelines provided by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America, as outlined in the study published in Clinical Infectious Diseases 1.

The recommended dosage translates to approximately 227 mg on day 1, followed by 114 mg daily for days 2-5. Since azithromycin typically comes in 250 mg tablets or 200 mg/5mL suspension, the child would likely receive 200 mg on day 1 and 100 mg on days 2-5 if using the suspension. The suspension is generally preferred for children this age.

Azithromycin is effective against Mycoplasma pneumoniae because it concentrates in tissues and has a long half-life, allowing for once-daily dosing, as noted in the guidelines 1. It works by inhibiting bacterial protein synthesis. Common side effects may include diarrhea, abdominal pain, and nausea. The medication should be given with food if stomach upset occurs, though it can be taken with or without food.

It is essential to complete the full 5-day course even if symptoms improve before finishing the medication, as emphasized in the guidelines 1. This ensures that the infection is fully cleared and reduces the risk of resistance development.

Some key points to consider when administering azithromycin to children include:

  • The dosage should not exceed the maximum recommended dose.
  • The medication should be taken as directed, with or without food.
  • Common side effects should be monitored, and medical attention should be sought if they persist or worsen.
  • The full course of treatment should be completed, even if symptoms improve before finishing the medication.

Overall, the recommended azithromycin dosage for a 50-pound (22.7 kg) 6-year-old child with Mycoplasma infection is 10 mg/kg on day 1, followed by 5 mg/kg on days 2-5, with a maximum daily dose of 250 mg. This dosage is supported by the guidelines provided by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America 1.

From the Research

Azithromycin Dosage for a 50lb 6-year-old with Mycoplasma

  • The American Academy of Pediatrics recommends azithromycin as a first-line treatment for Mycoplasma pneumoniae infections in children 2.
  • The usual dosage of azithromycin for children is 10-12 mg/kg/day for 5 days, which would be approximately 250-300 mg per day for a 50lb (22.7kg) child 2.
  • However, it's essential to note that the effectiveness of azithromycin may be reduced in cases of macrolide-resistant Mycoplasma pneumoniae, which has been reported to be increasing worldwide 3, 4.

Efficacy of Azithromycin against Mycoplasma pneumoniae

  • Azithromycin has been shown to be effective against Mycoplasma pneumoniae, with a 5-day course of oral azithromycin being a recommended treatment option 2, 5.
  • However, studies have reported varying degrees of macrolide resistance among Mycoplasma pneumoniae isolates, which may affect the efficacy of azithromycin treatment 3, 4, 6.
  • In a study of pediatric patients with Mycoplasma pneumoniae pneumonia, azithromycin was found to be effective in reducing the duration of fever, but its efficacy was lower in patients with macrolide-resistant strains 4.

Considerations for Treatment

  • The choice of antibiotic treatment for Mycoplasma pneumoniae infections should be based on the severity of the infection, the patient's age and weight, and the presence of any underlying medical conditions 2.
  • Alternative antibiotic treatments, such as minocycline or fluoroquinolones, may be considered in cases of macrolide-resistant Mycoplasma pneumoniae or in patients who do not respond to azithromycin treatment 4, 6.

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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