| Item |
Information |
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Drug Groups
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approved |
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Description
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A competitive serotonin type 3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties. [PubChem] |
| Indication |
For the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, postoperation, and radiation. Also used for the treatment of postoperative nausea and vomiting. |
| Pharmacology |
Ondansetron is a highly specific and selective serotonin 5-HT3 receptor antagonist, not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors. The serontonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery, and centrally in the chemoreceptor trigger zone of the area postrema. The temporal relationship between the emetogenic action of emetogenic drugs and the release of serotonin, as well as the efficacy of antiemetic agents suggest that chemotherapeutic agents release serotonin from the enterochromaffin cells of the small intestine by causing degenerative changes in the GI tract. The serotonin then stimulates the vagal and splanchnic nerve receptors that project to the medullary vomiting center, as well as the 5-HT3 receptors in the area postrema, thus initiating the vomiting reflex, causing nausea and vomiting. |
| Toxicity |
Low blood pressure and fainting, sudden blindness, severe constipation |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Hepatic |
| Absorption |
Ondansetron is well absorbed after oral administration and undergoes limited first-pass metabolism. |
| Half Life |
5.7 hours |
| Protein Binding |
70%-76% (Plasma protein binding) |
| Clearance |
* 0.38 L/h/kg [Normal Adult Volunteers (19-40 yrs)]
* 0.32 L/h/kg [Normal Adult Volunteers (61-74 yrs)]
* 0.26 L/h/kg [Normal Adult Volunteers (>=75 yrs)] |
| References |
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Ramsook C, Sahagun-Carreon I, Kozinetz CA, Moro-Sutherland D: A randomized clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Ann Emerg Med. 2002 Apr;39(4):397-403.
[Pubmed]
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| • |
Yilmaz HL, Yildizdas RD, Sertdemir Y: Clinical trial: oral ondansetron for reducing vomiting secondary to acute gastroenteritis in children--a double-blind randomized study. Aliment Pharmacol Ther. 2010 Jan;31(1):82-91. Epub .
[Pubmed]
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| • |
Gregory RE, Ettinger DS: 5-HT3 receptor antagonists for the prevention of chemotherapy-induced nausea and vomiting. A comparison of their pharmacology and clinical efficacy. Drugs. 1998 Feb;55(2):173-89.
[Pubmed]
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| • |
Gan TJ: Selective serotonin 5-HT3 receptor antagonists for postoperative nausea and vomiting: are they all the same? CNS Drugs. 2005;19(3):225-38.
[Pubmed]
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| External Links |
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