RANDOMIZED DOUBLE-BLIND, PLACEBO-CONTROLLED EVALUATION OF ORAL ONDANSETRON IN THE PREVENTION OF NAUSEA AND VOMITING ASSOCIATED WITH FRACTIONATED TOTAL-BODY IRRADIATION

Purpose: To evaluate oral ondansetron in the prevention of total-body irradiation (TBI)-induced nausea and vomiting. Methods: Twenty patient s who received 4 days of TBI as part of their preparative regimen befo re bone marrow transplantation were randomized to receive either 8-mg oral doses of ondansetron or placebo. Administration of drug was doubl e-blinded. Initial rescue therapy consisted of intravenous (IV) ondans etron 0.15 mg/kg following two or more emetic episodes between success ive fractions of TBI or five total emetic episodes during the 4 days o f therapy. If, after receipt of IV ondansetron, patients had two or mo re emetic episodes between fractions of TBI or five total emetic episo des, additional anti-emetics were administered. Results: Patients who received oral ondansetron had significantly fewer emetic episodes comp ared with those who received placebo (P = .005) over the entire 4-day study period. Oral ondansetron was also significantly superior to plac ebo with respect to the time of onset of emesis or rescue (P = .003). Six of 10 patients treated with oral ondansetron completed the study w ithout additional antiemetic therapy, while none of 10 patients who re ceived placebo completed the study without rescue antiemetic therapy. Six placebo patients who received initial rescue therapy with IV ondan setron required no additional antiemetics. No relationships were appar ent between peak ondansetron concentration (Cmax) or area under the co ncentration versus time curve (AUC) and number of emetic episodes. Con clusion: Oral ondansetron is an effective therapy for the prevention o f emesis induced by TBI.