From the FDA Drug Label
The recommended dosage for adult and pediatric patients 6 months of age and older for prevention of nausea and vomiting associated with emetogenic chemotherapy is 0.15-mg/kg per dose for 3 doses (maximum of 16 mg per dose).
For a 16 kg child, the recommended dose would be:
- 0.15 mg/kg x 16 kg = 2.4 mg per dose The dose should be infused intravenously over 15 minutes. 1
From the Research
For a 16 kg child, the recommended IV Zofran (ondansetron) dose is 1.6 mg, administered slowly over 2-5 minutes, based on the standard pediatric dosing of 0.1 mg/kg per dose, with a maximum of 4 mg per dose, as supported by the most recent and highest quality study available 2. The medication can be repeated every 8 hours as needed for nausea and vomiting.
- When administering, dilute the medication in 50 mL of compatible solution such as normal saline or D5W if giving as an infusion rather than a direct IV push.
- Monitor the child for potential side effects including headache, dizziness, or QT interval prolongation, especially if the child has cardiac issues or is on other medications that affect cardiac conduction.
- Zofran works by blocking serotonin receptors (5-HT3) in the chemoreceptor trigger zone and gastrointestinal tract, effectively reducing the nausea and vomiting reflex.
- For ongoing nausea management, the dose can be scheduled rather than given as needed, but should not exceed three doses in 24 hours. The optimal dose of ondansetron in pediatric patients has been studied, and it has been 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 2.
- The most recent study comparing ondansetron and metoclopramide in patients with renal colic found that ondansetron was more effective in preventing vomiting 3.
- However, the study by 2 provides the most relevant information for determining the optimal dose of ondansetron in pediatric patients.