Tropisetron

Absorption

The absorption of tropisetron from the gastrointestinal tract is rapid (mean half-life of about 20 minutes) and nearly complete (more than 95%). Due to first-pass metabolism in the liver, the absolute bioavailability of a 5 mg oral dose is 60%. The peak plasma concentration is attained within three hours.

Toxicity

LD50: 265 mg/kg (Rat, oral).

Description

Tropisetron is the third selective 5HT₃-antagonist, after ondansetron and granisetron, to be introduced for the management of nausea and vomiting induced by cancer chemotherapy. Similar to the other two 5HT3-antagonists, vopisetron is superior to metoclopramide. The compound has also been reported to have antiarrhythmic activity.

Originator

Sandoz (Switzerland)

The Uses of Tropisetron

A substance that is used to prevent nausea and vomiting caused by chemotherapy.

Indications

For the prevention of nausea and vomiting induced by cytotoxic therapy and postoperative.

Background

Tropisetron is an indole derivative with antiemetic activity. As a selective serotonin receptor antagonist, tropisetron competitively blocks the action of serotonin at 5HT3 receptors, resulting in suppression of chemotherapy- and radiotherapy-induced nausea and vomiting.
Tropisetron appears to be well tolerated with the most frequently reported adverse effect being headache. Extrapyramidal side effects are rare upon using tropisetron.

Definition

ChEBI: An indolyl carboxylate ester obtained by formal condensation of the carboxy group of indole-3-carboxylic acid with the hydroxy group of tropine.

brand name

Novaban

Hazard

Human systemic effects.

Metabolism

The metabolism of tropisetron occurs by hydroxylation at the 5, 6 or 7 positions of its indole ring, followed by a conjugation reaction to the glucuronide or sulphate with excretion in the urine or bile (urine to faeces ratio 5:1). The metabolites have a greatly reduced potency for the 5-HT3 receptor and do not contribute to the pharmacological action of the drug.