ondansetron at a glance
Medicine class
Selective serotonin 5-HT3 receptor antagonist antiemetic
Main licensed roles
Prevention or treatment of nausea and vomiting associated with chemotherapy, radiotherapy or surgery, depending on the product
Administration
Orodispersible tablets and films dissolve on the tongue and are then swallowed
What is ondansetron used for?
Oral products have product-specific licences.
Management of nausea and vomiting caused by chemotherapy in adults and children aged 6 months or older.
Management of nausea and vomiting caused by radiotherapy in adults.
Prevention, and for some products treatment, of nausea and vomiting after surgery in adults.
Setofilm is also licensed for post-operative nausea and vomiting in children aged 4 years or older; the selected orodispersible tablet does not support oral use for paediatric post-operative nausea and vomiting.
Ondansetron is sometimes used for severe nausea and vomiting in pregnancy when other options are unsuitable or inadequate, following an informed assessment of benefits and risks.
How does ondansetron work?
Ondansetron selectively blocks 5-HT3 serotonin receptors in the gut and nervous system. This interrupts signals that can trigger the vomiting reflex after chemotherapy, radiotherapy or surgery.
ondansetron preparations and strengths
Dispersible tablet
Route: Oral
Strengths: 4 mg, 8 mg
How to take ondansetron
Use ondansetron exactly as directed for the treatment or procedure involved.
Place an orodispersible tablet on top of the tongue, allow it to disperse, then swallow.
For an orodispersible film, open the sachet at the tear tag without cutting it. With dry fingers and an empty mouth, place an undamaged film on the tongue and allow it to dissolve without water.
Setofilm may be taken with food or drink.
If vomiting occurs after administration, follow the product leaflet or contact the treating team rather than taking extra medicine without checking.
ondansetron side effects
Common or expected effects
- Headache
- Constipation
- Feeling warm or flushed
Get urgent medical advice
- Severe allergic reaction, including breathing difficulty, swelling or collapse
- Sudden chest pain or chest tightness
- Abnormal heart rhythm, particularly with fainting
- Seizure or marked involuntary movements
- Serotonin syndrome, which may include agitation or confusion, sweating, fever, diarrhoea, tremor or muscle stiffness
- Widespread blistering or peeling skin rash
ondansetron in pregnancy
Ondansetron is not routinely recommended during the first trimester by the selected product information because studies suggest a small increase in oral clefts; the MHRA estimated about three additional cases per 10,000 exposed pregnancies. It may still be considered for severe pregnancy sickness after discussion of alternative treatments and the risks of uncontrolled vomiting. Do not stop prescribed treatment without speaking to the maternity or prescribing team.
ondansetron while breastfeeding
ondansetron interactions
Check prescribed, over-the-counter and herbal products before treatment.
Apomorphine
The combination is contraindicated because profound low blood pressure and loss of consciousness have occurred.
Medicines that prolong the QT interval
Examples include amiodarone, erythromycin, ketoconazole, methadone and some cancer treatments; combining them may further increase the risk of an abnormal heart rhythm.
Common questions about ondansetron
Answers are fully visible for fast scanning and source review.
What is ondansetron used for?
It is mainly used to prevent or treat nausea and vomiting associated with chemotherapy, radiotherapy or surgery. The exact licence depends on the product and the person's age.
How do I take an ondansetron orodispersible tablet?
Place it on top of the tongue, allow it to disperse and then swallow.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.