Maximum Daily Dose of Ondansetron (Zofran) for a 25kg Child
For a 25kg child, the maximum daily dose of ondansetron is 24mg, typically divided into three doses of 8mg every 8 hours. 1
Weight-Based Dosing Recommendations
- For children weighing 10-25kg, ondansetron can be safely administered at 0.15mg/kg per dose 2
- For a 25kg child specifically, this translates to approximately 3.75mg per dose 2
- Standard dosing is typically rounded to available formulations, with 4mg being the common dose for this weight range 1
- The maximum frequency is three times daily (every 8 hours), resulting in a maximum daily dose of 24mg 1
Administration Considerations
- Ondansetron can be administered orally or intravenously, with oral administration being more common in outpatient settings 2
- For oral administration, ondansetron is available in 4mg and 8mg tablet formulations 1
- The first dose should ideally be given 30 minutes before the anticipated nausea-inducing event (such as chemotherapy or surgery) 1
Safety Profile in Children
- Ondansetron is generally well tolerated in children, with headache, constipation, and diarrhea being the most commonly reported adverse effects 2, 3
- Unlike other antiemetics such as metoclopramide, ondansetron does not cause extrapyramidal symptoms, making it safer for pediatric use 3
- Transient elevations in liver enzymes have been reported in 6-8% of children receiving ondansetron, particularly those also receiving cisplatin chemotherapy 3
Special Considerations
- For children with severe hepatic impairment (Child-Pugh score ≥10), the total daily dose should not exceed 8mg due to reduced clearance and increased half-life 1
- No dosage adjustment is necessary for children with renal impairment 1
- The FDA has reported cases consistent with serotonin syndrome after inadvertent oral overdoses exceeding 5mg/kg in young children, so careful dosing is essential 1
Clinical Efficacy
- Ondansetron has demonstrated superior efficacy compared to placebo, droperidol, and metoclopramide in preventing chemotherapy-induced and postoperative nausea and vomiting in children 2
- In acute gastroenteritis, ondansetron at 0.2mg/kg has been shown to significantly reduce vomiting episodes compared to placebo 4
Remember that while the maximum daily dose is 24mg, the actual prescribed dose should be the minimum effective dose needed to control symptoms, to minimize potential side effects.