Ondansetron is primarily used to prevent nausea and vomiting associated with chemotherapy, radiation therapy, and surgery. It is generally well tolerated but can rarely cause QT prolongation and potentially fatal arrhythmias (torsades de pointes), especially with IV administration above 16 mg. Single IV doses should not exceed 16 mg. Use with caution in patients with electrolyte abnormalities, pre-existing heart conditions, or those taking other QT-prolonging medications. ECG monitoring is recommended for high-risk patients.
Ondansetron molecular structure diagram from the DrugsPRO substance library.
Also known as: Zofran, Zuplenz
Classification
Chemical: Medicine
Tag: Antiemetic
Tag: Carbazole derivative
Tag: Not psychoactive
Tag: Pharmaceutical
Effects
Reduction Of Nausea
Reduction Of Vomiting
Headache
Diarrhea
Fatigue
Nausea
Dizziness
Routes of Administration
Oral
Dosage
Threshold: 1 mg
Light: 2-4 mg
Common: 4-8 mg
Strong: 8-16 mg
Heavy: 24 mg (oncology context only)
Duration
Onset: 0.5-1 h
Peak: 1-2 h
Offset: 4-12 h
After Effects: 0-6 h
Total Duration: 4-12 h
Intravenous
Dosage
Threshold: 1 mg
Light: 2-4 mg
Common: 4-8 mg
Strong: 8-16 mg
Heavy: >16 mg (not recommended due to QT risk)
Duration
Peak: 0.25-0.5 h
Offset: 4-12 h
Onset: 0-0.25 h
After Effects: 0-4 h
Total Duration: 4-8 h
Intramuscular
Dosage
Common: 4-8 mg
Duration
Onset: 0.25-0.5 h
Peak: 0.5-1 h
Offset: 4-12 h
Harm Reduction
Check interactions before mixing substances, pay attention to dose spacing and hydration, and treat all dosage guidance as approximate rather than guaranteed safe.
Sources
Substance data is aggregated from the following public harm-reduction and reference sources.
This static page is intended as a readable non-JS and prerender-friendly library export.
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Ondansetron - Treoir substaint DrugsPRO
Ondansetron: Ondansetron is primarily used to prevent nausea and vomiting associated with chemotherapy, radiation therapy, and surgery. It is generally well tolerated but can rarely cause QT prolongation and potentially fatal arrhythmias (torsades de pointes), especially with IV administration above
