Nausea and vomiting in fractionated radiotherapy: a prospective on-demand trial of tropisetron rescue for non-responders to metoclopramide.

A prospective trial was performed to better assess the risk of nausea and vomiting and the rescue value of tropisetron (TRO), a 5-HT3 receptor antagonist, in 88 patients undergoing fractionated radiotherapy to the abdomen or to large supradiaphragmatic fields and failing a first anti-emetic trial with metoclopramide (MET). Nausea was graded 0 (absent), 1 (mild), 2 (moderate) and 3 (severe). Nausea requiring anti-emetics (> or = grade 2) was present in 64% of the patients. MET was able to control nausea (< or = grade 1) in 26 of 58 patients (45%) who developed > or = grade 2 nausea during radiation treatment (2 patients vomiting without nausea included). 34 patients required TRO, and 31 experienced immediate relief. However, nausea (> or = grade 2) recurred in 7 patients from 1 to 3 weeks after starting TRO. Sex, age, field type and field size (cm2) did not influence the incidence and severity of nausea and vomiting. Only 24/88 patients vomited after starting radiotherapy. MET helped to eliminate emesis in one third of these patients. TRO helped to control vomiting in 73% of the salvaged patients. Constipation was observed in 8 patients on TRO and was a reason to stop the medication in 4 cases.