Ondansetron


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult: PO Prophylaxis of chemotherapy-induced nausea and vomiting Moderately emetogenic chemotherapy: Initial: 8 mg 0.5-2 hours prior to chemotherapy, then 8 mg dose after 8 or 12 hours. Highly emetogenic chemotherapy: 24 mg as a single dose 0.5-2 hours prior to chemotherapy. Post-operative nausea and vomiting 16 mg as a single dose 1 hour prior to anaesthesia. Alternatively, 8 mg 1 hour prior to anaesthesia followed by 2 further 8 mg doses at 8 hourly intervals. Prevent delayed emesis following cancer chemotherapy 8 mg bid for up to 5 days after a course of treatment. Prophylaxis of nausea and vomiting associated with radiation therapy Total body irradiation: 8 mg 1-2 hours prior to daily fraction of radiotherapy. Single high-dose fraction to the abdomen: 8 mg 1-2 hours prior to irradiation. Fractionated radiation to the abdomen: 8 mg 1-2 hours prior to irradiation, followed by 8 hourly doses repeated daily during the radiotherapy course. IV/IM Prophylaxis of chemotherapy-induced nausea and vomiting Moderately emetogenic chemotherapy: 8 mg or 0.15 mg/kg as a single dose. Highly emetogenic chemotherapy: 8 mg as a single dose immediately prior to treatment, may be followed by either a 1 mg/hour continuous IV infusion for up to 24 hours, or by 2 further doses of 8 mg at 4-hour intervals. Alternatively, 16 mg via IV infusion immediately prior to treatment or 0.15 mg/kg via IV infusion 30 minutes prior to chemotherapy, may be followed by 2 further doses at of 8 mg at 4-hour intervals. Max: 16 mg/dose. Post-operative nausea and vomiting 4 mg via slow IV or IM inj given as single dose at induction of anaesthesia. Prophylaxis of nausea and vomiting associated with radiation therapy 8 mg via slow IV or IM inj as a single dose immediately before treatment. Rectal Nausea and vomiting associated with cancer chemotherapy or radiotherapy As supp: 16 mg given 1-2 hours prior to treatment. Prevent delayed emesis following cancer chemotherapy As supp: 16 mg once daily for up to 5 days after a course of treatment.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity. Congenital long QT syndrome. Concomitant use with apomorphine.
Special Precautions
Patient with hypokalaemia, hypomagnesaemia, CHF, CV conduction abnormalities, bradyarrhythmia, other conditions that may develop prolongation of QT interval or electrolyte abnormalities, phenylketonuria, subacute intestinal obstruction and abdominal surgery. May mask progressive ileus or gastric distension and occult bleeding in adenotonsillar surgery. Moderate to severe hepatic impairment. Elderly and children. Pregnancy and lactation. Monitoring Parameters Monitor ECG, serum K, and serum Mg. Monitor for signs and symptoms of serotonin syndrome and decreased bowel activity.
Adverse Reactions
Significant: Chest pain, bradycardia, hypotension, arrhythmia, hypoxia, transient elevation of liver enzymes, transient blurred vision (due to rapid IV inj). Rarely, transient blindness, extrapyramidal symptoms (e.g. dystonic reactions, oculogyric crisis, dyskinesia), seizures, toxic epidermal necrolysis, serotonin syndrome. Gastrointestinal disorders: Constipation, diarrhoea, hiccup, xerostomia, dyspepsia. General disorders and administration site conditions: Malaise, fatigue, fever, cold sensation, injection site reaction, local burning sensation following supp insertion. Investigations: ECG changes. Nervous system disorders: Headache, dizziness, sedation, drowsiness, paraesthesia. Psychiatric disorders: Insomnia, anxiety. Renal and urinary disorders: Urinary retention. Reproductive system and breast disorders: Gynaecological disease. Skin and subcutaneous tissue disorders: Rash, pruritus. Vascular disorders: Flushing, syncope.
Potentially Fatal: QT interval prolongation, torsade de pointes. Rarely, liver failure, anaphylaxis and bronchospasm.
ROUTE(S) : IV: B
ROUTE(S) : IV / PO / Parenteral: B Avoid during 1st trimester due to small increase risk of oral cleft defects.
Drug Interactions
Dexamethasone Na phosphate may potentiate antiemetic effect. May develop serotonin syndrome (including altered mental status, autonomic instability, neuromuscular abnormalities) with SSRIs, MAOIs, mirtazapine, fentanyl, lithium, methylene blue, serotonin noradrenaline reuptake inhibitors (SNRIs). Potent CYP3A4 inducers (e.g. phenytoin, carbamazepine, rifampicin) may reduce plasma concentrations and increase clearance of ondansetron. Coadministration with antiarrhythmics (e.g. amiodarone), atenolol, anthracyclines (e.g. doxorubicin, daunorubicin), trastuzumab, erythromycin, and ketoconazole may cause additive prolongation of QT interval and increase risk of arrhythmia. May decrease analgesic effect of tramadol.
ATC Classification
A04AA01 - ondansetron ; Belongs to the class of serotonin (5HT3) antagonists. Used for the prevention of nausea and vomiting.
Disclaimer: This information is independently developed by CIMS based on ondansetron from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to CIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, CIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 CIMS. All rights reserved. Powered by CIMSAsia.com
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