A RANDOMIZED COMPARATIVE-STUDY OF ANTIEMETIC PROPHYLAXIS WITH ONDANSENTRON IN A SINGLE 32-MG LOADING DOSE VERSUS 8 MG EVERY 6 H IN PATIENTSUNDERGOING CISPLATIN-BASED CHEMOTHERAPY

In several studies a single dose of 32 mg was compared to an ondansent ron (OND) administration schedule of every 6 h, yielding no difference s in overall efficacy. The aim of this randomized comparative study wa s to identify differences of these two schedules on an hour-to-hour co ntrol of nausea and vomiting, during the first 24 h in patients receiv ing cisplatin (CDDP)-based chemotherapy. One hundred ten patients were randomly assigned to two groups (A and B); all received combination c hemotherapy with CDDP at a dose of 100 mg/m(2). OND was administered a s follows: group A: 8 mg, 30 min before the infusion of CDDP, and repe ated 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 durin g 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 emet ic episodes during the first 24 h, there were important differences be tween these two antiemetic schedules: for group A an increased vomitin g with or without gastric content between midnight and 6 p.m. was obse rved, 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-hou r 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 contro l between dosing intervals.