A Randomized Comparative Study of Antiemetic Prophylaxis with Ondansentron in a Single 32-mg Loading Dose versus 8 mg Every 6 h in Patients Undergoing Cisplatin-Based Chemotherapy

In several studies a single dose of 32 mg was compared to an ondansentron (OND) administration schedule of every 6 h, yielding no differences in overall efficacy. The aim of this randomized comparative study was to identify differences of these two schedules on an hour-to-hour control of nausea and vomiting, during the first 24 h in patients receiving cisplatin (CDDP)-based chemotherapy. One hundred ten patients were randomly assigned to two groups (A and B); all received combination chemotherapy with CDDP at a dose of 100 mg/m2. OND was administered as follows: group A: 8 mg, 30 min before the infusion of CDDP, and repeated every 6 h after the first dose (totally 4 doses) in the first 24 h, and group B: 32 mg before CDDP, as a loading dose and this was the total dose for the first 24 h. No overall difference was noticed during the first 24 h, as well as the next 3 days from the infusion of CDDP in the intensity of vomits, vomits without gastric content (retches), and nausea. In a more detailed monitoring of the distribution of emetic episodes during the first 24 h, there were important differences between these two antiemetic schedules: for group A an increased vomiting with or without gastric content between midnight and 6 p.m. was observed, and for group B between 6 p.m. and midnight (vomits with p 0.03, and without gastric content p 0.02). Preloading with the total 24-hour dose of OND 32 mg exhibits a more potent antiemetic activity during the initial 18 h, becoming weaker over the last 5 h of the first day, whereas the every-6-hour schedule leaves periods of poor emesis control between dosing intervals.