Recommended Dosage of Ondansetron (Zofran) in Children
The recommended dosage of ondansetron (Zofran) for children varies by weight, with oral dosing of 0.1-0.15 mg/kg per dose for children under 40 kg, and standard dosing of 4-8 mg for children over 40 kg. 1, 2
Weight-Based Dosing Guidelines
Oral Dosing
- For children ≤15 kg (≤33 lb): 30 mg twice daily for treatment 3
- For children >15-23 kg (33-51 lb): 45 mg twice daily for treatment 3
- For children >23-40 kg (51-88 lb): 60 mg twice daily for treatment 3
- For children >40 kg (>88 lb): 75 mg twice daily for treatment 3
Age-Based Considerations
- Infants 9-11 months: 3.5 mg/kg per dose, twice daily 3
- Term infants 0-8 months: 3 mg/kg per dose, twice daily 3
- Children ≥7 years: Zanamivir 10 mg (two 5-mg inhalations), twice daily 3
Administration Guidelines
For Chemotherapy-Induced Nausea and Vomiting
- FDA-approved dosage for pediatric patients receiving chemotherapy: 0.15 mg/kg IV per dose, administered 30 minutes before chemotherapy, then repeated at 4 and 8 hours after the first dose 1
- Alternative regimen: Single doses of 4-8 mg have shown effectiveness in children with cancer 4
- For children aged 4-18 years with cancer: Initial IV dose ranges from 0.04 to 0.87 mg/kg (total dose 2.16-12 mg) followed by oral doses ranging from 4-24 mg daily for 3 days 1
For Postoperative Nausea and Vomiting
- Intravenous dosing: 0.1-0.15 mg/kg has been shown to be effective for preventing postoperative nausea and vomiting 2
- Oral dosing: 0.1 mg/kg has been shown to be effective for preventing postoperative nausea and vomiting 2
Special Considerations
Renal Impairment
- No dosage adjustment is necessary for children with renal impairment 3
Hepatic Impairment
- Ondansetron undergoes extensive hepatic metabolism; consider lower doses in children with hepatic dysfunction 5
Clinical Efficacy
- Complete or major response rates of 85.3% in non-cisplatin chemotherapy and 71.4% in cisplatin-containing chemotherapy have been reported 6
- Ondansetron is significantly more effective than metoclopramide or chlorpromazine for chemotherapy-induced nausea and vomiting in children 2
- For acute gastroenteritis, ondansetron at 0.2 mg/kg has shown effectiveness in reducing vomiting episodes 7
Safety Profile
- Generally well-tolerated in children with mild to moderate side effects including headache, constipation, and diarrhea 2
- No dosage reduction is needed based on age alone 3
- Ondansetron has a favorable safety profile compared to other antiemetics, rarely necessitating treatment withdrawal 2
Practical Dosing Tips
- For ease of administration, doses may be rounded according to available formulations 3
- Ondansetron is available as tablets (4 mg, 8 mg) and oral solution (4 mg/5 mL) 1
- For children who cannot swallow tablets, the oral solution formulation is recommended 1
Remember that ondansetron dosing should be based on the child's weight and clinical condition, with careful attention to the indication for which it is being prescribed.