Clinical pharmacology of ondansetron

Ondansetron (ODS) is a new carbazole which exerts selective and potent antagonism on serotoninergic neurotransmission at serotonin 3 (5-HT3) receptors. Animal and clinical studies show that ODS reduces the incidence and severity of nausea and vomiting induced by cytotoxic drugs and radiotherapy. The antiemetic properties of this agent have been determined in ferrets against the nausea and vomiting induced by cisplatin, cyclophosphamide and whole-body radiation. The current hypothesis is that there may be both a peripheral and a central site of action for ODS. The lack of antagonist activity on dopamine and other non 5-HT3 receptors indicates that, unlike metoclopramide, ODS will not cause extrapyramidal or other dose-limiting side effects. ODS is rapidly and completely absorbed when administered as a tablet. Preliminary data show that ondansetron can be combined with dexamethasone safely with enhanced antiemetic results.