Granisetron. An update of its therapeutic use in nausea and vomiting induced by antineoplastic therapy.

Granisetron is a selective serotonin3 (5-hydroxytryptamine3, 5-HT3) receptor antagonist which has significant antiemetic activity against chemotherapy-induced nausea and vomiting. A single prophylactic intravenous dose is sufficient to control acute nausea and vomiting in approximately 60 to 70% of patients. In comparative studies, the acute antiemetic efficacy of granisetron is equivalent or superior to that of traditional antiemetic regimens even in patients receiving highly emetogenic cisplatin-containing chemotherapy. However, limited data have suggested that granisetron therapy offers no advantages over traditional antiemetics in terms of the control of delayed emesis. Recently, a number of large randomised studies have directly compared the efficacy and tolerability of granisetron, ondansetron and tropisetron and reported no significant differences between the 3 drugs in controlling acute nausea and vomiting, although 1 study reported a modest statistical advantage for granisetron over ondansetron but not tropisetron in the complete control of vomiting. In crossover studies, significantly more patients preferred granisetron to either ondansetron or tropisetron. The efficacy of granisetron appears to be maintained with repeated doses over several cycles of chemotherapy, although the influence of various prognostic factors affecting antiemetic response has not been adequately analysed. Concomitant administration of dexamethasone significantly improves the acute antiemetic efficacy of granisetron, increasing response rates by approximately 15%. Granisetron is an effective antiemetic in children undergoing highly emetogenic chemotherapy, and effectively controls radiotherapy-induced and postoperative nausea and vomiting. Trials using an oral formulation are scarce at present, but preliminary results suggest a similar efficacy and tolerability profile to that of the intravenous formulation. Granisetron has been well tolerated in clinical trials. The most frequently reported adverse event has been headache (14%). Extrapyramidal effects, which can limit the use of traditional antiemetics such as metoclopramide, have not been reported with granisetron. Thus, recent data confirm that granisetron is an effective and well tolerated agent for the prophylactic treatment of chemotherapy-induced acute nausea and vomiting, with efficacy equivalent or superior to that of other currently available agents. It has a promising role to play in paediatric oncology, and is an effective agent in controlling radiotherapy-induced acute emesis. Granisetron offers comparable or superior efficacy in controlling acute nausea and vomiting with a much simpler dosage regimen than that of traditional antiemetic regimens.