General Information

Subjects receiving chemotherapy and radiation therapy can suffer from severe nausea and vomiting as side effects to cancer treatment. Kytril solution has been approved for the prevention of nausea and vomiting associated with initial and repeat courses of cancer therapy, including high-dose cisplatin, and nausea and vomiting associated with radiation, including total body irradiation and fractionated abdominal radiation. Kytril is currently available in both tablet and injection formulations.

Kytril works by blocking the serotonin 5-HT3 receptor. When a subjects receives chemotherapy, the hormone serotonin is released by cells in the small intestine. Serotonin acts on the vagus nerve to trigger nausea and vomiting. Kytril reduces this effect by blocking receptors on the vagus nerve, reducing detrimental stimulation by serotonin.

Side Effects

Adverse events reported in clinical trials with Kytril tablets or Kytril injection include (but are not limited to) the following:

• Headache
• Constipation
• Asthenia (weakness)
• Diarrhea
• Abdominal pain
• Dyspepsia (indigestion)
• Somnolence (sleepiness)

Mechanism of Action

Granisetron is a selective 5-hydroxytryptamine3 (5-HT3) receptor antagonist with little or no affinity for other serotonin receptors, including 5-HT1; 5-HT1A; 5-HT1B/C; 5-HT2; for alpha1-, alpha2-, or beta-adrenoreceptors; for dopamine-D2; or for histamine-H1; benzodiazepine; picrotoxin or opioid receptors.

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. (from Kytril Product Information)

Additional Information

For more information on Kytril and other Roche products, please visit www.rocheusa.com.

If you would like additional information on cancer, including treatment methods, please visit the following web sites:

National Cancer Institute

American Cancer Society