The safety of intravenous (IV) and oral
ondansetron has been evaluated in over 7,000
cancer patients in world-wide clinical trials. In adult patients receiving single-day
chemotherapy, the incidence of adverse events was 45% with IV
ondansetron (n = 317) and 59% with
metoclopramide (n = 279).
Headache occurred in 17% of
ondansetron patients and 10% of
metoclopramide patients, whereas
diarrhea symptoms were reported in 15% of the former and 29% of the latter. The incidence and types of adverse events were similar following three 0.15 mg/kg IV
ondansetron doses and 8- or 32-mg single IV doses. There was a slight increase in the incidence of
headache following a single 32-mg dose (25%) compared with a single 8-mg dose (18%) or three 0.15 mg/kg doses (18%). The safety profile of oral
ondansetron was similar to that of the IV formulation. Following an 8-mg oral dose administered three times a day for 3 days, the most frequently reported adverse events were
headache (21%),
constipation (7%), and
abdominal pain (5%). In a group of 209 pediatric patients receiving
chemotherapy, the incidence of adverse events following IV and oral
ondansetron was 19%. The most commonly reported adverse event was
headache (4%). In comparative clinical trials, extrapyramidal symptoms were reported in 5% of the
metoclopramide patients but none of the
ondansetron patients. In open-label trials, two patients who received
ondansetron reported symptoms consistent with, but not diagnostic of, extrapyramidal reactions. The incidence of vascular occlusive events and
seizure disorders was identical for
ondansetron and comparative agents. Serum
transaminase values increased significantly in 6% to 8% of
ondansetron patients and 2% of
metoclopramide patients who received
cisplatin. There was no apparent relationship between the dose of
ondansetron administered and the incidence of increased
transaminase abnormalities. However, there was an apparent relationship between the dose of
cisplatin administered and the incidence of
transaminase abnormalities. In patients who received non-
cisplatin chemotherapy, there was no difference in serum
transaminase values between oral
ondansetron and placebo. These data demonstrate that
ondansetron is better tolerated than
metoclopramide and is safe for IV and
oral administration to patients receiving
chemotherapy. In addition,
ondansetron is well tolerated when administered as a single 32-mg infusion over 15 minutes.