Ondansetron
Also sold as: Zofran
Prescription neededNausea and vomiting
Comes as:TabletOral solutionInjection
Usual adult dose
Dose is set by your doctor. Usual adult dose: 4 to 8 mg up to 2 or 3 times a day for nausea and vomiting. Higher, scheduled doses are used with cancer treatment.
Your doctor may give you a different dose. Children's doses depend on weight.
Side effects
Common
- headache
- constipation
- feeling of warmth or flushing
- tiredness
Serious — get help
Stop taking it and see a doctor straight away if you notice:
- fast or irregular heartbeat or fainting
- agitation with fever and muscle twitching (serotonin syndrome)
- severe allergic reaction
Do not take it, or take care, if
- Heart rhythm problems (long QT) or low potassium or magnesium
- Severe liver disease (maximum 8 mg a day)
- First 3 months of pregnancy (ask your doctor)
Interactions
Medicines that can react with this one.
Serious1 medicineDo not take these together unless your doctor says so.
- Amiodarone
Both prolong the QT interval and together raise the risk of dangerous heart rhythms.
Moderate2 medicinesTake together only with care. Ask your doctor or pharmacist.
- Fluoxetine
The combination can increase the risk of serotonin syndrome.
- Tramadol
Ondansetron may reduce the pain relief of tramadol and raise the risk of serotonin syndrome.