ondansetron hydrochloride dihydrate at a glance
Medicine class
Selective serotonin 5-HT3 receptor antagonist and antiemetic.
Licensed roles
Cancer treatment-related nausea and vomiting, and prevention or treatment of postoperative nausea and vomiting where supported by the formulation.
What is ondansetron hydrochloride dihydrate used for?
The selected products support the following uses; the licensed population and suitable route vary by formulation.
Management of nausea and vomiting caused by cytotoxic chemotherapy in adults and children within the licensed age range.
Management of radiotherapy-related nausea and vomiting in adults.
Prevention of postoperative nausea and vomiting in adults; injection is also licensed for prevention and treatment in children within the stated age range.
Treatment of established postoperative nausea and vomiting using the injection formulation.
Non-licensed context: ondansetron is also used for significant nausea and vomiting in pregnancy, including hyperemesis gravidarum, after an individual benefits-and-risks discussion.
How does ondansetron hydrochloride dihydrate work?
Ondansetron selectively blocks 5-HT3 serotonin receptors on nerves in the gut and brain. This interrupts vomiting signals triggered when chemotherapy, radiotherapy or surgery causes serotonin-mediated activation of these pathways.
ondansetron hydrochloride dihydrate preparations and strengths
Oral solution
Route: Oral
Strengths: 8 mg/5 mL
Syrup
Route: Oral
Strengths: 4 mg/5 mL, 8 mg/5 mL
Tablet
Route: Oral
Strengths: 4 mg, 8 mg
How to take ondansetron hydrochloride dihydrate
Use ondansetron exactly as stated on the dispensing label and for the reason prescribed. It may be taken with or without food where the product leaflet permits.
Swallow film-coated tablets with water. A tablet breakline may be intended only to make swallowing easier, not to produce equal portions.
Measure oral liquid with the supplied spoon or oral syringe rather than a household teaspoon. Shake the bottle if instructed, replace the cap and wash the measuring device after use.
Injection or infusion should be prepared and administered by a healthcare professional.
If vomiting occurs soon after an oral dose, ask the treating team or pharmacist before taking more.
ondansetron hydrochloride dihydrate side effects
Common or expected effects
- Headache
- Constipation
- Warmth or flushing
- Irritation around an intravenous administration site
Get urgent medical advice
- Severe allergic reaction, including breathing difficulty or facial or throat swelling
- QT prolongation or another abnormal heart rhythm, which may cause palpitations, fainting or collapse
- Sudden chest pain or tightness associated with myocardial ischaemia
- Seizures or abnormal involuntary movements
- Serotonin syndrome, particularly with other serotonergic treatments
- Severe skin reactions
ondansetron hydrochloride dihydrate in pregnancy
Ondansetron is used outside its product licence for significant pregnancy sickness when the expected benefit justifies the potential risk. UK pregnancy information describes a possible very small increase in cleft lip or palate after early-pregnancy exposure, while evidence for cardiac malformations is conflicting; most exposed pregnancies are not affected. Treatment choices should be discussed with the maternity or prescribing team, particularly during the first trimester.
ondansetron hydrochloride dihydrate interactions
Check all prescribed, pharmacy and complementary treatments before ondansetron is used.
Apomorphine
The combination is contraindicated because profound hypotension and loss of consciousness have been reported.
QT-prolonging or cardiotoxic medicines
Antiarrhythmics, some antibiotics, antifungals, cancer treatments and other QT-prolonging medicines can add to the risk of serious arrhythmia.
Common questions about ondansetron hydrochloride dihydrate
Answers are fully visible for fast scanning and source review.
Is ondansetron licensed for ordinary stomach bugs?
The selected products are licensed mainly for nausea and vomiting related to chemotherapy, radiotherapy or surgery, not routine gastroenteritis.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.