What is the appropriate dose of Ondansetron (Zofran) for a 13 kg child experiencing vomiting?

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Last updated: February 27, 2025View editorial policy

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From the Guidelines

For a 13 kg child experiencing vomiting, the appropriate dose of Ondansetron (Zofran) is 0.65 mg/kg, which equals approximately 8.45 mg, but according to the most recent and highest quality evidence available, specifically for children between 1 month and 11 years, the dose is 5 mg/kg once a day (oral) as per 1. However, this dose seems excessively high for a child. Given the provided evidence and considering the standard approach for calculating the dose of ondansetron in children, a more appropriate and commonly used dose in clinical practice for a child of this weight would be around 0.15 mg/kg, which for a 13 kg child equals 1.95 mg, rounded to 2 mg, but this is not supported by the provided evidence. The key considerations in managing a child with vomiting include ensuring hydration and monitoring for side effects such as headache, constipation, or rarely, QT prolongation. It's crucial to note that while the evidence from 1 provides dosage guidelines for children, it does not specifically address the use of ondansetron for vomiting in children, and the dose provided seems more aligned with other conditions. In real-life clinical practice, the dose of 0.15 mg/kg (approximately 2 mg for a 13 kg child) is commonly used for vomiting, but this is based on clinical guidelines not directly referenced here. The decision to use ondansetron and the appropriate dose should be made considering the individual child's condition, the cause of vomiting, and under the guidance of a healthcare professional, especially since the provided evidence does not directly address the treatment of vomiting in children with ondansetron.

From the Research

Ondansetron Dosing for Pediatric Patients

  • The appropriate dose of Ondansetron for a 13 kg child experiencing vomiting can be determined based on several studies 2, 3, 4, 5, 6.
  • According to the studies, the recommended dose of Ondansetron for children is between 0.1 to 0.15 mg/kg for intravenous administration and 0.1 mg/kg for oral administration 2, 5.
  • For a 13 kg child, the calculated dose would be:
    • Intravenous: 0.1 to 0.15 mg/kg x 13 kg = 1.3 to 1.95 mg
    • Oral: 0.1 mg/kg x 13 kg = 1.3 mg
  • A study published in 2019 compared the efficacy of oral ondansetron with domperidone in children with acute gastroenteritis and found that ondansetron was more effective in cessation of vomiting 3.
  • Another study published in 2010 found that within the dose range of 0.13-0.26 mg/kg, higher doses of ondansetron were not superior to lower doses, nor were they associated with increased side effects 4.
  • A randomized controlled trial published in 2016 found that a single oral dose of ondansetron facilitated successful rehydration in children aged 3 months to 5 years with acute diarrhea and vomiting 6.

Administration and Efficacy

  • Ondansetron can be administered intravenously or orally, depending on the clinical situation and the child's ability to tolerate oral medication 2, 5.
  • The studies suggest that ondansetron is effective in preventing emesis in children undergoing surgery, chemotherapy, and radiotherapy, as well as in those with acute gastroenteritis and viral gastritis 2, 3, 5, 6.
  • Ondansetron has been shown to be well-tolerated in children, with mild to moderate adverse events such as headache, constipation, and diarrhea being the most commonly reported 2, 5.

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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