{"ok":true,"entry":{"slug":"ondansetron","kind":"medication","name":"ondansetron","aliases":["Zofran"],"brands_sg":["Zofran","Odnatron","Ondavell","Natzo","Vomiz"],"class":"5-HT3 antiemetic","tags":["digestive"],"use_for":"prescribed to prevent or treat nausea and vomiting","use_after":"healthhub: usually as needed; regularly only if directed","use_duration":null,"take_with":"healthhub: with or without food","pros":["healthhub: blocks the serotonin signal behind nausea","fda label: used before chemo, radiotherapy and surgery","sg register: 4 mg and 8 mg tablets, plus injections"],"cons":["healthhub: constipation, headache and drowsiness","fda label: it can prolong the qt interval","healthhub: rarely, serotonin syndrome can occur"],"dose_note":"the us label for ondansetron tablets gives 'A single 24 mg dose administered 30 minutes before the start of single-day highly emetogenic chemotherapy' as the largest adult dose it prints, 16 mg an hour before induction of anaesthesia for postoperative nausea, and states 'In patients with severe hepatic impairment (Child-Pugh score of 10 or greater), do not exceed a total daily dose of 8 mg'. sg-registered oral strengths are 4 mg and 8 mg. in singapore the prescriber sets the dose.","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["healthhub: a liver condition, or abnormal heart rhythm","healthhub: recent surgery in the stomach area","fda label: congenital long qt syndrome","healthhub: pregnancy or breastfeeding"],"clashes":[{"src":["fda_ond_contra","hh_ond_inter"],"note":"fda label: contraindicated — risk of profound hypotension and loss of consciousness; healthhub names it too","with":"apomorphine"},{"src":["fda_ond_inter"],"note":"fda label: serotonin syndrome has been described with concomitant use, so symptoms are monitored for","with":"serotonergic drugs (ssris, snris)"},{"src":["hh_ond_inter","fda_ond_warn"],"note":"healthhub asks that these heart medicines be declared; the fda label flags other qt-prolonging drugs","with":"amiodarone or sotalol"},{"src":["hh_ond_inter"],"note":"healthhub asks that domperidone, also used for nausea and vomiting, be declared","with":"domperidone"},{"src":["fda_ond_inter"],"note":"fda label: potent cyp3a4 inducers significantly increased clearance and lowered ondansetron blood levels","with":"phenytoin, carbamazepine, rifampicin"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/datasets/d_767279312753558cbf19d48344577084/view","label":"HSA — Listing of Registered Therapeutic Products (data.gov.sg open dataset, 5,511 rows, cached in full and filtered locally)","quote":"All 17 registered ondansetron products carry Forensicclassification 'Prescription Only', ATC A04AA01 — SIN05133P ZOFRAN TABLET 8 mg · SIN13714P ODNATRON · SIN15004P ONDAVELL · SIN15423P NATZO · SIN17125P VOMIZ, plus injections.","accessed":"2026-08-27"},{"id":"hh_ond_uses","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub (Pharmaceutical Society of Singapore) — Ondansetron: what is this medication for","quote":"Ondansetron is used to prevent or treat nausea and vomiting. Ondansetron works by blocking the actions of a chemical called serotonin that causes nausea and vomiting.","accessed":"2026-08-27"},{"id":"hh_ond_admin","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: how should I take or use this medication","quote":"You may take Ondansetron with or without food.","accessed":"2026-08-27"},{"id":"hh_ond_missed","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: missed dose","quote":"Ondansetron is generally taken on an as-needed basis. Take them regularly only when directed by the doctor. If you forget to take a dose, take it as soon as you remember.","accessed":"2026-08-27"},{"id":"hh_ond_prec","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: precautions","quote":"You have a history of: Liver condition; Abnormal heart rhythm; Recent surgery in the stomach area. You are pregnant or breastfeeding. You are taking any other medications, including supplements, traditional medications and herbal remedies.","accessed":"2026-08-27"},{"id":"hh_ond_side","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: common side effects","quote":"Constipation … Diarrhea … Headache … Drowsiness. Avoid driving or engaging in activities that require concentration … Anxiety","accessed":"2026-08-27"},{"id":"hh_ond_serious","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: rare but serious side effects","quote":"Ondansetron is generally safe, but very rarely a serious condition known as Serotonin syndrome may occur. This can cause serious health problems that may sometimes be life threatening.","accessed":"2026-08-27"},{"id":"hh_ond_inter","url":"https://www.healthhub.sg/medication-devices-and-treatment/medications/ondansetron","label":"HealthHub — Ondansetron: what food or medication should I avoid","quote":"Certain heart medications (e.g. Amiodarone, Sotalol); Domperidone which is used for treating nausea and vomiting; Apomorphine, which is used for treating Parkinson's disease","accessed":"2026-08-27"},{"id":"fda_ond_dose","url":"https://api.fda.gov/drug/label.json?search=openfda.generic_name:%22ondansetron%20hydrochloride%22&limit=1","label":"US label for ondansetron tablets, section 2 Dosage and Administration, via openFDA drug/label.json (effective 2024-04-24)","quote":"A single 24 mg dose administered 30 minutes before the start of single-day highly emetogenic chemotherapy … Postoperative 16 mg administered 1 hour before induction of anesthesia … do not exceed a total daily dose of 8 mg","accessed":"2026-08-27"},{"id":"fda_ond_ind","url":"https://api.fda.gov/drug/label.json?search=openfda.generic_name:%22ondansetron%20hydrochloride%22&limit=1","label":"US label for ondansetron tablets, section 1 Indications and Usage, via openFDA","quote":"indicated for the prevention of nausea and vomiting associated with: highly emetogenic cancer chemotherapy … moderately emetogenic cancer chemotherapy … radiotherapy … Ondansetron tablets are also indicated for the prevention of postoperative nausea and/or vomiting.","accessed":"2026-08-27"},{"id":"fda_ond_contra","url":"https://api.fda.gov/drug/label.json?search=openfda.generic_name:%22ondansetron%20hydrochloride%22&limit=1","label":"US label for ondansetron tablets, section 4 Contraindications, via openFDA","quote":"Ondansetron is contraindicated in patients: … receiving concomitant apomorphine due to the risk of profound hypotension and loss of consciousness","accessed":"2026-08-27"},{"id":"fda_ond_warn","url":"https://api.fda.gov/drug/label.json?search=openfda.generic_name:%22ondansetron%20hydrochloride%22&limit=1","label":"US label for ondansetron tablets, section 5 Warnings and Precautions, via openFDA","quote":"QT Interval Prolongation and Torsade de Pointes: Avoid ondansetron tablets in patients with congenital long QT syndrome; monitor with electrocardiograms (ECGs) if concomitant electrolyte abnormalities, cardiac failure or arrhythmias, or use of other QT prolonging drugs.","accessed":"2026-08-27"},{"id":"fda_ond_inter","url":"https://api.fda.gov/drug/label.json?search=openfda.generic_name:%22ondansetron%20hydrochloride%22&limit=1","label":"US label for ondansetron tablets, section 7 Drug Interactions, via openFDA","quote":"Serotonin syndrome … has been described following the concomitant use of 5-HT3 receptor antagonists and other serotonergic drugs, including SSRIs and SNRIs … potent inducers of CYP3A4 (i.e., phenytoin, carbamazepine, and rifampin)","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:27.496708+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}