Efficacy of ondansetron treatment with different timing schedules: a randomized double-blind study

The purpose of this study was to determine whether preloading administration of ondansetron given 12.5 h before cisplatin therapy, every 6 h, is better in controlling acute cisplatin-induced emesis than a standard dose every 8 h. All patients had previously received three cycles of CDDP-based chemotherapy in a dose of 100 mg/m2. Ondansetron was given according to two schedules: in group A (40 patients) at a dose of 8 mg in 100 ml normal saline over 10 min by intravenous infusion before the infusion of CDDP continued with 1 tablet of 8 mg after 8 and 16 h; in group B (40 patients) it was administered in six intravenous doses (every 6 h) starting 12.5 h before cisplatin administration. During the following 3 days, patients from both groups continued with tablets of 8 mg orally, every 8 h in group A and every 6 h in group B. The only difference in terms of the antiemetic response noticed between the two groups was in the number of patients that presented with nausea, which was increased in group A (32) in comparison to group B (25; p < 0.022). No difference was found in the number of vomiting episodes, retches or control of emesis, during the 3-day evaluation period after cisplatin infusion, and in secondary side effects. In conclusion the total dose of 24 mg ondansetron during the acute phase of emesis is as effective as preloading and increasing the total dose to 32 mg.