Randomized, double-blind, crossover, placebo-controlled trial of intravenous ondansetron for the prevention of intrathecal chemotherapy-induced vomiting in children

Background The purpose of this study was to determine the effectiveness of intravenous ondansetron in preventing vomiting after the administration of intrathecal chemotherapy in children. Patients and Methods Twenty-six children (ages 18 mo to 15 y) receiving intrathecal chemotherapy with either methotrexate or the combination of methotrexate, hydrocortisone, and Ara-C for the prophylactic treatment of central nervous system leukemia were randomly assigned to receive an infusion of normal saline or ondansetron at one of two doses (0.15 or 0.45 mg/kg) 30 minutes before undergoing the procedure. One hundred forty-six infusions were administered (51 placebo, 47 at the lower ondansetron dose, and 48 at the higher dose). Each patient acted as his or her own control, and each patient was studied at least three times. Results Twenty-three of 26 patients (88.5%) had postprocedural vomiting on at least one occasion. At least one episode of vomiting occurred during the 24 hours after the procedure in fifty-two of the procedures (35.6%). The incidence of vomiting was significantly greater after infusion of placebo than after either low-dose or high-dose ondansetron. The likelihood of severe vomiting was even more significantly reduced by the preadministration of ondansetron. Almost all of the intrathecal treatments associated with severe vomiting occurred after the infusion of placebo. Conclusions Vomiting induced by intrathecal chemotherapy can be greatly reduced by the intravenous administration of ondansetron before the procedure, and severe vomiting can be virtually eliminated.