How long before a meal should you take ondansetron?

If you are taking ondansetron for nausea that occurs with meals, then the standard tablet should be taken half an hour to 1 hour before meals, and the orally disintegrating tablet or oral soluble film can be taken 15 minutes before meals.However, if you are taking ondansetron for constant, all day nausea then it should be taken at regular intervals during the day as prescribed, with or without food.

Ondansetron (Zofran) is an anti-nausea medicine. It is used to prevent nausea and vomiting that is caused by cancer medicines or radiation therapy, or nausea after surgery.

Ondansetron works in the stomach to block the signals to the brain that cause nausea and vomiting. The standard tablets that are swallowed will start to work within half an hour to 2 hours. Medicines generally work faster on an empty stomach, an hour before food or 2 hours after. The orally disintegrating tablets or oral soluble films are absorbed very quickly into the blood stream so start to work rapidly. Always take your medicine as prescribed by your doctor.

For more information on Ondansetron see: https://www.drugs.com/ondansetron.html