Generic
Ondansetron
128 brands available in the market
At a glance
Ondansetron is an anti-emetic used for prevention and treatment of nausea and vomiting associated with chemotherapy, radiotherapy and surgery. It acts as a 5-HT3 receptor antagonist to block serotonin effects.
Description
Ondansetron is a potent, highly selective 5HT3 receptor-antagonist. Chemotherapeutic agents and radiotherapy may cause release of 5HT in the small intestine initiating a vomiting reflex by activating vagal afferents via 5HT3 receptors. Ondansetron blocks the initiation of this reflex. It blocks 5HT3 receptors in both central and peripheral nervous systems to control nausea and vomiting.
Indications
- Prevention of chemotherapy-induced nausea and vomiting
- Prevention of radiotherapy-induced nausea and vomiting
- Prevention and treatment of postoperative nausea and vomiting
Therapeutic class
Anti-emetic Drugs
Pharmacological class
5-HT3 Receptor Antagonist
Pharmacology
Ondansetron blocks 5-HT3 receptors to prevent serotonin effects, inhibiting the vomiting reflex initiated by 5HT released from the small intestine during chemotherapy and radiotherapy.
Mechanism of action
Controls nausea and vomiting by blocking serotonin receptors.
Dosage
Chemotherapy-induced Nausea:
- Highly emetogenic: 24 mg (oral) 30 min before chemotherapy
- Moderately emetogenic: 8 mg 30 min before chemotherapy, then 8 mg after 8 hours; then 8 mg twice daily (every 12 hours) for 1-2 days
- IV: 0.15 mg/kg (max 16 mg) IV infusion over 15 min, 30 min before chemotherapy
Postoperative Nausea: 16 mg (oral) 1 hour before anesthesia; IV: 4 mg
Pediatric Dose (4-11 years): 4 mg 30 min before chemotherapy, then 4 and 8 hours after; then 4 mg three times daily for 1-2 days
Administration
- Oral: May be taken with or without food
- Oral soluble film: Place on tongue, dissolves in 20 seconds; do not chew or swallow whole
- IV: Infuse over 15 minutes; not less than 30 seconds
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Headache
- Constipation
- Diarrhea
- Fatigue
- Flushing or warmth sensation
- Hiccups
- Liver enzyme abnormalities
Rare: Anaphylaxis, bronchospasm, tachycardia, angina, hypokalemia
Precautions & warnings
- Caution in patients with hypersensitivity to other 5-HT3 receptor antagonists
- May mask ileus or gastric distension after abdominal surgery
- Severe hepatic impairment: Max 8 mg/day
- Caution while driving
Contraindications
- Concurrent use with apomorphine (profound hypotension)
Drug interactions
- May reduce analgesic effect of tramadol
- Rifampicin and other CYP3A4 inducers may reduce levels/effects
- QT-prolonging agents may cause additive QT prolongation
- Increased risk of arrhythmias with cardiotoxic drugs
Food interactions
No harmful interaction with alcohol.
Use in pregnancy
Use in Pregnancy: Ondansetron is considered safe during pregnancy; animal studies show low or no adverse effects.
Pregnancy Category: B — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Ondansetron is probably safe during breastfeeding; no significant risk to baby.
Pediatric use
Dose established for children 4 months+ (chemotherapy, PONV).
Geriatric use
No dose adjustment needed in elderly.
Renal / hepatic impairment
Renal Impairment: Safe in kidney disease; no dose adjustment needed.
Hepatic Impairment: Severe hepatic impairment: Max 8 mg/day; caution in liver disease.
Overdose effects
Overdose: Visual disturbances, constipation, hypotension; ECG monitoring, symptomatic treatment.
Storage conditions
Store at temperature not exceeding 30°C in a dry place; protect from light and moisture.
Chemical structure
Ondansetron