What is the recommended dose of Zofran (Ondansetron) ODT (orally disintegrating tablet) for a 6-year-old child?

Zofran ODT Dosing for a 6-Year-Old Child

For a 6-year-old child, the recommended dose of ondansetron (Zofran) ODT is 4 mg as a single dose, administered 30 minutes before chemotherapy or surgery, or at the onset of symptoms for gastroenteritis-related vomiting. 1, 2

Weight-Based Dosing Considerations

The FDA-approved dosing for ondansetron in pediatric patients is primarily weight-based rather than strictly age-based:

• For children weighing less than 40 kg: The standard dose is 4 mg 1
• For children weighing 40 kg or more: The adult dose of 8 mg may be used 1

Since most 6-year-old children weigh significantly less than 40 kg (typically 18-25 kg), the 4 mg dose is appropriate for this age group 1, 2.

Clinical Context-Specific Dosing

For Chemotherapy-Induced Nausea and Vomiting

• Initial dose: 4 mg administered 30 minutes before chemotherapy 1, 3
• Subsequent dosing: May repeat every 8 hours as needed 3
• In clinical trials, pediatric patients aged 4-18 years received ondansetron with complete response rates (no emetic episodes) of 58% on Day 1 of chemotherapy 1

For Gastroenteritis-Related Vomiting

• Single dose: 4 mg at presentation 2
• In a randomized controlled trial of children aged 6 months to 12 years with gastroenteritis, ondansetron significantly reduced vomiting episodes in the emergency department compared to placebo (P=0.001) 2
• This single dose reduced the need for IV fluid therapy (P=0.015) and hospital admission (P=0.007) 2

For Postoperative Nausea and Vomiting

• Preoperative dose: 0.1 mg/kg (maximum 4 mg for most 6-year-olds) given intravenously or orally 1 hour before anesthesia induction 1, 3
• Ondansetron demonstrated superior efficacy compared to placebo, droperidol, and metoclopramide in preventing postoperative emesis in pediatric surgical patients 3

Administration Instructions

The orally disintegrating tablet (ODT) formulation:

• Does not require water for administration 1, 4
• Should be placed on the tongue where it dissolves rapidly 4
• Provides bioequivalence to standard oral tablets 4
• Is particularly useful for children with difficulty swallowing or active vomiting 4

Important Safety Considerations

Common Adverse Effects

• Headache, constipation, and diarrhea are the most frequently reported side effects 3
• In gastroenteritis trials, patients receiving ondansetron had significantly more diarrhea during the 48-hour follow-up period compared to placebo 2
• All adverse events are generally mild to moderate and rarely require treatment discontinuation 3

Clinical Pitfalls

• Do not exceed the weight-appropriate dose: Using adult doses (8 mg) in children under 40 kg is not recommended 1
• Monitor for return visits: In gastroenteritis studies, the revisit rate was higher in the ondansetron group (P=0.047), though admission rates were lower 2
• The medication is well-tolerated with minimal serious adverse events in pediatric populations 3

Comparative Efficacy

Ondansetron has demonstrated superior antiemetic efficacy compared to:

• Metoclopramide and chlorpromazine (both combined with dexamethasone) in chemotherapy-induced nausea 3
• Droperidol (0.02-0.075 mg/kg) and metoclopramide (0.2-0.25 mg/kg) in postoperative settings 3
• Placebo in all clinical contexts studied 2, 3