About ondansetron
5-HT3 serotonin receptor antagonist
Used for
- Prevention of nausea and vomiting from chemotherapy
- Prevention of nausea and vomiting after surgery
- Prevention of nausea and vomiting from radiotherapy
Usual adult dose
Commonly 8 mg before chemotherapy or radiotherapy, then repeated as directed; doses vary by treatment and indication.
Usual dose in children
For chemotherapy: usually 0.15 mg/kg per dose, up to 8 mg, at treatment-specific intervals; specialist dosing applies.
Common side effects
- Headache
- Constipation
- Diarrhea
- Tiredness
Important warnings
- Can prolong the QT heart rhythm; risk is higher with certain heart conditions or low potassium or magnesium.
- Seek urgent care for fainting, severe allergic symptoms, or signs of serotonin syndrome.
- Severe liver impairment requires a lower maximum daily dose.
- Oral lyophilisates may contain phenylalanine; check the product leaflet for ingredients.
Pregnancy
Use during pregnancy only when needed; studies suggest a small possible increase in oral clefts with first-trimester exposure.
Breastfeeding
Information is limited; ondansetron is generally considered compatible with breastfeeding, with infant monitoring for unusual sleepiness or feeding problems.
Interactions
- Apomorphine: combination is contraindicated because of severe low blood pressure and loss of consciousness.
- Other QT-prolonging medicines can increase abnormal heart rhythm risk.
- Serotonergic medicines may increase serotonin syndrome risk.
- Some enzyme-inducing medicines, including phenytoin, carbamazepine, and rifampicin, can reduce ondansetron levels.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.