What is the recommended dose of ondansetron (Zofran) per kilogram for pediatric patients?

From the Guidelines

The recommended dose of ondansetron for pediatric patients is 0.15 mg/kg, as established in clinical practice. This dose is based on the most recent and highest quality study available, which evaluated the optimal dose and scheduling of 5-HT3 receptor antagonists in children 1. According to this study, established doses for ondansetron are 5 mg/m2 or 0.15 mg/kg.

Key Considerations

• Weight-based dosing is preferred over age-based dosing to ensure appropriate therapeutic levels.
• Ondansetron works by blocking serotonin (5-HT3) receptors in the chemoreceptor trigger zone and gastrointestinal tract, preventing the nausea and vomiting reflex.
• Common side effects include headache and constipation, and the medication should be used with caution in patients with congenital long QT syndrome due to potential cardiac effects.
• For children receiving chemotherapy, the combination of a 5-HT3 antagonist plus a corticosteroid is suggested before chemotherapy in children receiving chemotherapy of high or moderate emetic risk 1.
• The addition of aprepitant to a 5-HT3 receptor antagonist in pediatric patients has been evaluated in two studies, which showed improved complete response rates during both the 0- to 24-hour and 24- to 120-hour periods after chemotherapy 1.

Administration and Formulations

• Ondansetron can be administered intravenously or orally every 6-8 hours as needed for nausea and vomiting.
• Oral formulations include tablets, orally disintegrating tablets (ODTs), and liquid.
• The maximum single dose of 4 mg for children under 40 kg and 8 mg for those over 40 kg should not be exceeded.

It is essential to note that the optimal dose and scheduling of 5-HT3 receptor antagonists in children have been evaluated in several trials, but these studies are small, and it is difficult to identify the optimal oral and intravenous doses of 5-HT3 receptor antagonists in children 1. However, based on the available evidence, 0.15 mg/kg is the recommended dose of ondansetron for pediatric patients.

From the FDA Drug Label

The initial dose of ondansetron injection ranged from 0.04 to 0.87 mg per kg (total dose of 2.16 mg to 12 mg) The recommended dose of ondansetron for pediatric patients is 0.04 to 0.87 mg per kg.

• The dose range is based on clinical trials with 182 pediatric patients aged 4 to 18 years with cancer. 2

From the Research

Ondansetron Pediatric Dose per Kilogram

The recommended dose of ondansetron for pediatric patients varies depending on the study and the specific context. Here are some key points to consider:

• A study from 1999 3 compared the antiemetic efficacy of single high-dose ondansetron (0.6 mg/kg, maximum dose 32 mg) and multiple standard-dose ondansetron (0.15 mg/kg, maximum dose 8 mg, every 4 hours for four doses) in pediatric oncology patients.
• Another study from 2008 4 evaluated the safety of an ondansetron loading dose of 16 mg/m(2) (top, 24 mg) in children with cancer, but did not provide a dose per kilogram.
• A 2018 study 5 compared the therapeutic values of palonosetron and ondansetron in preventing pediatric chemotherapy-induced nausea and vomiting, with ondansetron dosed at 3 × 150 μg/kg.
• A 2021 study 6 compared single daily dosing (0.3 mg/kg/dose) and divided dosing (0.15 mg/kg/dose every 8 hours) intravenous ondansetron for 24 hours in children undergoing chemotherapy.
• A 2005 study 7 assessed the effects of 0.1 mg/kg ondansetron on electrocardiography in children receiving chemotherapy for acute leukemia.

Key Findings

Some key findings related to the dose of ondansetron per kilogram include:

• 0.6 mg/kg (maximum dose 32 mg) as a single high-dose ondansetron 3
• 0.15 mg/kg (maximum dose 8 mg) every 4 hours for four doses as multiple standard-dose ondansetron 3
• 0.3 mg/kg/dose as single daily dosing ondansetron 6
• 0.15 mg/kg/dose every 8 hours as divided dosing ondansetron 6
• 0.1 mg/kg ondansetron in the 2005 study 7

Dosing Considerations

When considering the dose of ondansetron per kilogram for pediatric patients, it is essential to take into account the specific context and the findings of relevant studies, such as those mentioned above 3, 4, 5, 6, 7.