indication

For the prevention of nausea and vomiting associated with emetogenic cancer chemotherapy, including initial and repeat courses of chemotherapy. Also used for the prevention of postoperative nausea and vomiting. This drug can be used intravenously for the treatment of postoperative nausea and vomiting.

pharmacology

Dolasetron 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. It is structurally and pharmacologically related to other 5-HT₃ receptor agonists. 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. It is suggested 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.

mechanism of action

Dolasetron is a selective serotonin 5-HT₃ receptor antagonist. In vivo, the drug is rapidly converted into its major active metabolite, hydrodolasetron, which seems to be largely responsible for the drug's pharmacological activity. The antiemetic activity of the drug is brought about through the inhibition of 5-HT₃ receptors present both centrally (medullary chemoreceptor zone) and peripherally (GI tract). This inhibition of 5-HT₃ receptors in turn inhibits the visceral afferent stimulation of the vomiting center, likely indirectly at the level of the area postrema, as well as through direct inhibition of serotonin activity within the area postrema and the chemoreceptor trigger zone.

biotransformation

Hepatic

absorption

Orally-administered dolasetron is well absorbed

half life

8.1 hours

route of elimination

Hydrodolasetron is eliminated by multiple routes, including renal excretion and, after metabolism, mainly glucuronidation, and hydroxylation.

drug interactions

Artemether: Additive QTc-prolongation may occur. Concomitant therapy should be avoided.

Tacrolimus: Additive QTc-prolongation may occur increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Thiothixene: May cause additive QTc-prolonging effects. Increased risk of ventricular arrhythmias. Consider alternate therapy. Thorough risk:benefit assessment is required prior to co-administration.

Toremifene: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Consider alternate therapy. A thorough risk:benefit assessment is required prior to co-administration.

Trimipramine: Additive QTc-prolongation may occur, increasing the risk of serious ventricular arrhythmias. Concomitant therapy should be used with caution.

Voriconazole: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Vorinostat: Additive QTc prolongation may occur. Consider alternate therapy or monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).

Ziprasidone: Additive QTc-prolonging effects may increase the risk of severe arrhythmias. Concomitant therapy is contraindicated.

Zuclopenthixol: Additive QTc prolongation may occur. Consider alternate therapy or use caution and monitor for QTc prolongation as this can lead to Torsade de Pointes (TdP).