Zofran

Ondansetron

Clinical data
Trade names	Zofran, Ondisolv, others
AHFS/Drugs.com	Monograph
MedlinePlus	a601209
Pregnancy category	AU: B1 US: B (No risk in non-human studies)
Routes of administration	by mouth, rectal, IV, IM
ATC code	A04AA01 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	~60%
Protein binding	70%-76%
Metabolism	Liver (CYP3A4, CYP1A2, CYP2D6)
Biological half-life	5.7 hours
Excretion	Kidney
Identifiers
IUPAC name (RS)-9-methyl-3-[(2-methyl-1H-imidazol-1-yl)methyl]-2,3-dihydro-1H-carbazol-4(9H)-one
CAS Number	99614-02-5 Y
PubChem CID	4595
IUPHAR/BPS	2290
DrugBank	DB00904 Y
ChemSpider	4434 Y
UNII	4AF302ESOS
KEGG	D00456 Y
ChEMBL	CHEMBL46 Y
ECHA InfoCard	100.110.918
Chemical and physical data
Formula	C18H19N3O
Molar mass	293.4 g/mol
3D model (Jmol)	Interactive image
SMILES O=C3c2c1ccccc1n(c2CCC3Cn4ccnc4C)C
InChI InChI=1S/C18H19N3O/c1-12-19-9-10-21(12)11-13-7-8-16-17(18(13)22)14-5-3-4-6-15(14)20(16)2/h3-6,9-10,13H,7-8,11H2,1-2H3 Y Key:FELGMEQIXOGIFQ-UHFFFAOYSA-N Y

Ondansetron, marketed under the brand name Zofran, is a medication used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, or surgery. It is also useful in gastroenteritis. It has little effect on vomiting caused by motion sickness. It can be given by mouth, by injection into a muscle or into a vein.

Common side effects include diarrhea, constipation, headache, sleepiness, and itchiness. Serious side effects include QT prolongation and severe allergic reaction. It appears to be safe during pregnancy but has not been well studied in this group. It is a serotonin 5-HT₃ receptor antagonist. It does not have any effect on dopamine receptors or muscarinic receptors.

Ondansetron was first used medically in 1990. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication. The wholesale cost of the injectable form in the developing world is about 0.10 to 0.76 USD per dose. In the United States it costs about 1.37 USD per tablet.

Although an effective antiemetic agent, the high cost of brand-name ondansetron initially limited its use to controlling postoperative nausea and vomiting and chemotherapy-induced nausea and vomiting.