Maximum Daily Dosing of Ondansetron ODT (Orally Disintegrating Tablet)
Ondansetron ODT can be taken up to three times daily with a maximum daily dose of 24 mg (three 8 mg tablets). 1
Recommended Dosing Schedule
The appropriate dosing of ondansetron ODT depends on the clinical indication:
Standard Dosing
- Most common dosage: 8 mg ODT every 8 hours as needed 2
- Maximum daily dose: 24 mg (three 8 mg tablets) 1
- Timing: For prevention of nausea/vomiting, first dose should be given 30 minutes before the triggering event (e.g., chemotherapy, radiation) 2, 1
Specific Clinical Scenarios
For Chemotherapy-Induced Nausea and Vomiting
Moderately emetogenic chemotherapy: 8 mg ODT twice daily 3, 1
- First dose 30 minutes before chemotherapy
- Second dose 8 hours after first dose
- Continue for up to 2 days after completion of chemotherapy
Highly emetogenic chemotherapy: 8 mg ODT three times daily 3, 1
- First dose 30 minutes before chemotherapy
- Subsequent doses at 4 and 8 hours after first dose
- Continue for up to 2 days after completion of chemotherapy
For Radiation-Induced Nausea and Vomiting
- Total body irradiation: 8 mg ODT 2-3 times daily 3
- Upper abdominal radiation: 8 mg ODT 2-3 times daily 3
Administration Considerations
- ODT formulation should be placed on the tongue where it dissolves rapidly without water 4
- This makes it particularly useful for patients who have difficulty swallowing 5
- The bioavailability of ODT formulation is equivalent to conventional tablets 4, 6
- Onset of action is typically within 30 minutes, so timing before anticipated nausea is important 7
Important Precautions
- For breakthrough nausea/vomiting, it's often better to add a medication from a different antiemetic class rather than exceeding the maximum ondansetron dose 2
- Prolonged QT interval is a potential side effect, especially with higher doses 2
- Common side effects include headache, constipation, and dizziness 2
Clinical Pearls
- The ODT formulation provides equivalent efficacy to conventional tablets with the advantage of not requiring water 4, 6
- When used for chemotherapy-induced nausea, studies show that twice daily dosing (8 mg twice daily) is as effective as three times daily dosing for moderate emetogenic chemotherapy 1
- For optimal efficacy, the first dose should always be administered at least 30 minutes before the anticipated nausea-inducing event 2, 7