An open, two-armed, multicentre trial was conducted in 231 patients with malignant disease who had previously failed to respond to conventional antiemetic treatment for the prevention of chemotherapy-induced nausea and vomiting. Patients were randomized to receive either tropisetron (5 mg/day; n = 115) or a standard antiemetic therapy, which was considered optimal for each individual but did not include a 5-HT3 receptor antagonist (n = 116). Acute vomiting on Day 1 was controlled in 60 (52%) tropisetron patients, compared with only 29 (25%) patients receiving optimal standard therapy (p < 0.001). Acute nausea was completely inhibited in 37 (32%) tropisetron patients, compared with 22 (19%) patients on optimal standard therapy (p < 0.05). On Day 1, delayed vomiting was also significantly better prevented by tropisetron (p < 0.001). Side effects from tropisetron (headache and constipation) were mild, and no extrapyramidal symptoms were observed in any tropisetron patients, in contrast to 14 (13%) patients in the 'optimal standard' group. In conclusion, in cases of acute nausea and vomiting it is more effective to switch refractory patients to tropisetron rather than attempt to optimize the dose of standard antiemetic therapy. For delayed nausea and vomiting, combination antiemetic therapy, with differing types of receptor antagonism and cortico-steroids may provide the best way forward. Such studies are in progress.
