| Download the app: Android | Apple | |
|---|---|
| MEDICAL DISCLAIMER: Educational use only. Not for diagnosis or management. |
Ondansetron
📖 About
Always check the BNF link here.
- 💊 Ondansetron is a potent anti-emetic widely used in oncology, post-operative care, and palliative medicine.
- ✅ Particularly effective against chemotherapy- and radiotherapy-induced nausea and vomiting (CINV/RINV) and post-operative nausea/vomiting (PONV).
⚡ Mechanism of Action
- ⛔ 5-HT3 receptor antagonist.
- Blocks serotonin receptors centrally in the chemoreceptor trigger zone (CTZ) and peripherally in the GI tract/vagus nerve.
- ⬇️ Prevents serotonin-mediated stimulation of vomiting pathways.
🩺 Indications & Dosing – Ondansetron (verify in BNF/datasheet)
| Indication | Details |
|---|---|
| 🤢 General Nausea & Vomiting |
Ondansetron
• Dose: 4–8 mg • Route: PO / IV / IM • Frequency: OD–BD (per clinical need) |
| 🎗️ Chemo/Radiotherapy-induced Nausea |
Ondansetron
• 8 mg PO/IV before treatment • Then 8 mg q12h for 1–2 days (protocol dependent) |
| 🏥 Post-operative Nausea/Vomiting (PONV) |
Ondansetron
• 4 mg IV/IM • Given at induction or post-operatively |
- 💧 IV should be given over at least 2–5 min to reduce arrhythmia risk.
🔄 Interactions
- See BNF – avoid with other QT-prolonging drugs (e.g. amiodarone, macrolides, antipsychotics).
- ⚡ May increase risk of serotonin syndrome when combined with SSRIs, SNRIs, MAOIs, or other serotonergic agents.
⚠️ Cautions
- 💔 QT prolongation risk – caution in those with arrhythmias, electrolyte imbalance, or on other QT-prolonging meds.
- 📉 Severe hepatic impairment – max dose 8 mg daily.
- 👶 Neonates/infants – use with caution (immature hepatic metabolism).
🚫 Contraindications
- Hypersensitivity to ondansetron or other 5-HT3 antagonists.
- Concomitant use with apomorphine (severe hypotension and loss of consciousness reported).
💥 Side Effects
- 🤢 Constipation (common).
- 🧠 Headache, dizziness.
- 🌡️ Flushing, hiccups.
- 💔 QT prolongation, arrhythmias (rare but serious).
- ⚡ Rare: serotonin syndrome (with serotonergic drugs), seizures, anaphylaxis.
- 🫁 Rare: transient visual disturbances during IV administration.
📑 References
- BNF: Ondansetron
- MHRA Drug Safety Update: Ondansetron & QT prolongation
| Educational content only. Feedback welcome. |
|
|
Categories
- A Level
- About
- Acute Medicine
- Anaesthetics and Critical Care
- Anatomy
- Biochemistry
- Book
- Cardiology
- Collections
- CompSci
- Crib Sheets
- Dental
- Dermatology
- Differentials
- Drugs
- ENT
- Electrocardiogram
- Embryology
- Emergency Medicine
- Endocrinology
- Ethics
- Foundation Doctors
- GCSE
- Gastroenterology
- General Practice
- Genetics
- Geriatric Medicine
- Guidelines
- Gynaecology
- Haematology
- Hepatology
- Immunology
- Infectious Disease
- Infectious Diseases
- Infographic
- Investigations
- Lists
- Mandatory Training
- Medical Students
- Microbiology
- Nephrology
- Neurology
- Neurosurgery
- Nutrition
- OSCE
- Obstetrics
- Obstetrics Gynaecology
- Oncology
- Ophthalmology
- Oral Medicine and Dentistry
- Orthopaedics
- Paediatrics
- Palliative
- Pathology
- Pharmacology
- Physiology
- Procedures
- Psychiatry
- Public Health
- Radiology
- Renal
- Respiratory
- Resuscitation
- Revision
- Rheumatology
- Statistics and Research
- Stroke
- Surgery
- Toxicology
- Trauma and Orthopaedics
- USMLE
- Urology