Ondansetron 2 mg
Ondansetron is a selective 5-HT 3 receptor antagonist. While its mechanism of action has not been fully
characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT 3 type
are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the
area postrema. It is not certain whether ondansetron’s antiemetic action is mediated centrally, peripherally, or
in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the
enterochromaffin cells of the small intestine.
In humans, urinary 5-HIAA (5-hydroxyindoleacetic acid) excretion increases after cisplatin administration in
parallel with the onset of emesis. The released serotonin may stimulate the vagal afferents through the 5-HT 3
receptors and initiate the vomiting reflex. In animals, the emetic response to cisplatin can be prevented by
pretreatment with an inhibitor of serotonin synthesis, bilateral abdominal vagotomy and greater splanchnic
nerve section, or pretreatment with a serotonin 5-HT 3 receptor antagonist.
In normal volunteers, single intravenous doses of 0.15 mg/kg of ondansetron had no effect on esophageal
motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. Multiday
administration of ondansetron has been shown to slow colonic transit in normal volunteers. Ondansetron has
no effect on plasma prolactin concentrations. Ondansetron does not alter the respiratory depressant effects
produced by alfentanil or the degree of neuromuscular blockade produced by atracurium.
Management of nausea & vomiting induced by
1. CINV (Chemotherapy induced nausea & vomiting)
2. RINV (Radiotherapy induced nausea & vomiting)
3. PONV (Postoperative nausea & vomiting)
DOSAGE AND ADMINISTRATION
Prevention of Chemotherapy-Induced Nausea and Vomiting
Prevention of Nausea and Vomiting Associated With Highly Emetogenic Cancer Chemotherapy:
The dosage in pediatric cancer patients 6 months to 18 years of age should be three 0.15-mg/kg doses. The
first dose is to be administered 30 minutes before the start of moderately to highly emetogenic
chemotherapy, subsequent doses (0.15 mg/kg) are administered 4 and 8 hours after the first dose of VOMICAP The drug should be infused intravenously over 15 minutes. Little information is available about
dittcsage in pediatric cancer patients younger than 6 months of age.
Prevention of Nausea and Vomiting Associated With Moderately Emetogenic Cancer ‘Chemotherapy:
For paediatric patients 12 years of age and older, the dosage is the same as for adults
Prevention of Nausea and Vomiting Associated With Radiotherapy, Either Total Body Irradiation, or Sr
le High-Dose Fraction or Daily Fractions to the Abdomen:
The recommended I.V. dosage of VOMICAP for pediatric surgical patients (1 month to 12 years of age) is a
single 0.1-mg/kg dose for patients weighing 40 kg or less, or a single 4-mg dose for patients weighing (more
than 40 kg. The rate of administration should not be less than 30 seconds, preferably over 2 to 5 Minutes
immediately prior to or following anesthesia induction, or postoperatively if the patient experiences nausea
and/or vomiting occurring shortly after surgery.
Patients 6 months to 18 years of age should given be three 0.15-mg/kg doses