Stereochemistry | RACEMIC |
Molecular Formula | C18H19N3O |
Molecular Weight | 293.363 |
Optical Activity | ( + / - ) |
Defined Stereocenters | 0 / 1 |
E/Z Centers | 0 |
Charge | 0 |
SHOW SMILES / InChI
SMILES
CN1C2=C(C3=C1C=CC=C3)C(=O)C(CN4C=CN=C4C)CC2
InChI
InChIKey=FELGMEQIXOGIFQ-UHFFFAOYSA-N
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
Molecular Formula | C18H19N3O |
Molecular Weight | 293.363 |
Charge | 0 |
Count |
MOL RATIO
1 MOL RATIO (average) |
Stereochemistry | RACEMIC |
Additional Stereochemistry | No |
Defined Stereocenters | 0 / 1 |
E/Z Centers | 0 |
Optical Activity | ( + / - ) |
Ondansetron (ZOFRAN®) is a selective 5-HT3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by radiotherapy, anesthesia, surgery or cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. It is not certain whether ondansetron's antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. The released serotonin may stimulate the vagal afferents through the 5-HT3 receptors and initiate the vomiting reflex.
CNS Activity
Originator
Approval Year
Cmax
AUC
Overview
CYP3A4 | CYP2C9 | CYP2D6 | hERG |
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Drug as perpetrator
Drug as victim
Tox targets
Sourcing
Sample Use Guides
To prevent nausea and vomiting associated with cancer chemotherapy the recommended adult oral dosage of ondansetron (ZOFRAN®) is a single 24-mg tablet administered 30 minutes before the start of single-day highly emetogenic chemotherapy; for moderately emetogenic cancer chemotherapy the recommended adult oral dosage is one 8-mg ondansetron (ZOFRAN®) tablet given twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy: the first dose should be administered 30 minutes before the start of emetogenic chemotherapy, with a subsequent dose 8 hours after the first dose.
To prevent nausea and vomiting associated with radiotherapy the recommended adult oral dosage is one 8-mg ondansetron (ZOFRAN®) tablet given 3 times a day; for total body irradiation, one 8-mg ondansetron (ZOFRAN®) tablet should be administered 1 to 2 hours before each fraction of radiotherapy administered each day; for single high-dose fraction radiotherapy to the abdomen, one 8-mg ondansetron (ZOFRAN®) tablet should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for 1 to 2 days after completion of radiotherapy; for daily fractionated radiotherapy to the abdomen, one 8-mg ondansetron (ZOFRAN®) tablet should be administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours after the first dose for each day radiotherapy is given.
To prevent postoperative nausea and vomiting the recommended adult oral dosage is 16 mg given as two 8-mg ondansetron (ZOFRAN®) tablets 1 hour before induction of anesthesia.
Route of Administration:
Oral
On the isolated vagus nerve and superior cervical ganglion of the rat, R,S-GR38032F (ondansetron) behaved as a reversible competitive antagonist of 5-HT-induced depolarization with pKB values of 8.61+/-0.08 (n=19) and 8.13+/-0.07 (n=16), respectively. The resolved R- and S-isomers of GR38032F were approximately equipotent as 5-HT antagonists on the rat vagus nerve: the pKB values were 8.95+/-0.05 (n=16) and 8.63+/-0.08 (n=17), respectively. R,S-GR38032F was also an effective antagonist of 5-HT on the rabbit isolated vagus nerve: in this case the pKB value was 9.40+/-0.14 (n=4).