BRAND NAMES
 MECHANISM OF ACTION
Granisetron is a selective 5-hydroxytryptamine3 (5-HT3) receptor antagonist.
Serotonin receptors of the 5-HT3 type are located peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. During chemotherapy that induces vomiting, mucosal enterochromaffin cells release serotonin, which stimulates 5-HT3 receptors. This evokes vagal afferent discharge, inducing vomiting. Animal studies demonstrate that, in binding to 5-HT3 receptors, granisetron blocks serotonin stimulation and subsequent vomiting after emetogenic stimuli such as cisplatin. In the ferret animal model, a single granisetron injection prevented vomiting due to high-dose cisplatin or arrested vomiting within 5 to 30 seconds.
Granisetron is indicated for the prevention of:
- Nausea and vomiting associated with initial and repeat courses of emetogenic cancer therapy, including high-dose cisplatin.
- Nausea and vomiting associated with radiation, including total body irradiation and fractionated abdominal radiation.
The recommended adult and elderly dosage of oral Granisetron is 2 mg once daily given up to 1 hour before chemotherapy, or 1 mg twice daily: the first 1 mg is given up to 1 hour before chemotherapy, and the second 1 mg is given 12 hours after the first.
Either regimen is administered only on the day(s) chemotherapy is given. Continued treatment, while not on chemotherapy, has not been found to be useful.
Radiation (Either Total Body Irradiation or Fractionated Abdominal Radiation)
The recommended adult and elderly dosage of oral Granisetron is 2 mg once daily, taken within 1 hour of radiation.
- Known hypersensitivity to Granisetron.
- QT prolongation has been reported with Granisetron. Therefore, Granisetron should be used with caution in patients with pre-existing arrhythmias or cardiac conduction disorders, as this might lead to clinical
consequences. Patients with cardiac disease, on cardio-toxic chemotherapy, with concomitant electrolyte abnormalities and/or on concomitant medications that prolong the QT interval are particularly at risk.
- QT prolongation has been reported with Granisetron. Use of Granisetron in patients concurrently treated with drugs known to prolong the QT interval and/or are arrhythmogenic may result in clinical consequences.
 PREGNANCY AND LACTATION
- Pregnancy Category B (US)
- Nursing Mothers: It is not known whether granisetron is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Granisetron is administered to a nursing woman.
 SIDE EFFECTS
Granisetron is a well-tolerated drug with few side effects. Headache, Constipation, Dizziness, Asthenia, Diarrhea and Abdominal pain are the most commonly reported side effects associated with its use.
 RELATED LINKS
|5-HT3 receptor antagonists||Dolasetron • Granisetron • Ondansetron • Palonosetron • Tropisetron|
|Dopamine antagonists||Alizapride • Bromopride • Clebopride • Domperidone • Metoclopramide • Prochlorperazine • Thiethylperazine|
|H1 antagonists||Dimenhydrinate • Meclizine|
|NK1 receptor antagonists||Aprepitant • Fosaprepitant • Maropitant|
|Motion sickness||Cinnarizine • Dimenhydrinate • Meclizine • Meclizine/Pyridoxine • Scopolamine (Patch)|
|Pregnancy||Meclizine/Pyridoxine • Ondansetron|