Do not use this medication if you are allergic to ondansetron or to similar medicines such as dolasetron (Anzemet), granisetron (Kytril), or palonosetron (Aloxi).
Before taking ondansetron, tell your doctor if you have liver disease, or a personal or family history of Long QT syndrome.
Ondansetron orally disintegrating tablets may contain phenylalanine. Tell your doctor if you have phenylketonuria (PKU).
The serious side effects of this medication include blurred vision or temporary blindness, slow heart rate, trouble breathing, anxiety, agitation, shivering, feeling light-headed, or fainting, and urinating less than usual or not at all. Stop taking ondansetron and call your doctor at once if you have any of these side effects.
Ondansetron can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.