What is it used for?

• Preventing and treating nausea and vomiting caused by chemotherapy or radiotherapy for cancer in adults and children.
• Preventing and treating nausea and vomiting following surgery in adults (injection only).

How does it work?

• Kytril tablets contain the active ingredient granisetron, which is a type of medicine called a 5HT3 antagonist.  Granisetron is used to prevent and treat nausea and vomiting that can be caused by chemotherapy or radiotherapy treatment for cancer, or by surgery.
• Vomiting is controlled by an area of the brain called the vomiting centre. The vomiting centre is responsible for causing feelings of sickness (nausea) and for the vomiting reflex. It is activated when it receives nerve messages from another area of the brain called the chemoreceptor trigger zone (CTZ) and when it receives nerve messages from the gut.
• Chemotherapy, radiotherapy and surgery can cause a substance called serotonin (5HT) to be released in the gut. This 5HT acts on the 5HT3 receptors that are found in the gut and causes nerve messages to be sent to the vomiting centre.
• 5HT released by chemotherapy, radiotherapy and surgery also activates the 5HT3 receptors that are found in the CTZ in the brain, causing further messages to be sent to the vomiting centre.
• Granisetron works by blocking the 5HT3 receptors that are found in the brain and gut. This prevents the nausea messages being sent from these areas to the vomiting centre. Granisetron therefore prevents nausea, retching and vomiting that can otherwise occur following surgery or due to cancer treatments.

Granisetron can be given by mouth or by injection or drip (infusion) into a vein.

Use with caution in

• People with a blockage in the gut (intestinal obstruction).
• People with heart disease for example heart failure or an irregular heartbeat (arrhythmia).
• People with a personal or family history of an abnormal heart rhythm seen as a 'prolonged QT interval' on a heart monitoring trace or ECG.
• People with abnormal levels of electrolytes such as potassium or magnesium in their blood.
• People being treated with chemotherapy that can have side effects on the heart.
• Not to be used in
• Kytril tablets contain lactose and should not be taken by people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
• This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

• The safety of this medicine during pregnancy has not been studied. It should not be used during pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.
• It is not known if this medicine pases into breast milk. Women who need this medicine should not breastfeed during treatment. Seek medical advice from your doctor.

Side effects

• Headache.
• Constipation.
• Difficulty sleeping (insomnia).
• Diarrhoea.
• Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity (extrapyramidal effects).
• Skin rash.
• Allergic reactions such as blistering rash (hives) or anaphylaxis.
• Abnormal heart rhythm seen as a 'prolonged QT interval' on a heart monitoring trace or ECG.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

There may be an increased risk of an abnormal heart rhythm, seen as a prolonged QT interval on an ECG, if other medicines that can have this effect are used in combination with granisetron. These medicines include the following:

• antiarrhythmics (medicines to treat abnormal heartbeats), eg amiodarone, procainamide, disopyramide, sotalol
• the antihistamines astemizole, mizolastine or terfenadine
• arsenic trioxide
• atomoxetine
• certain antidepressants, eg amitriptyline, imipramine, maprotiline
• certain antimalarials, eg halofantrine, chloroquine, quinine, mefloquine, Riamet
• certain antipsychotics, eg thioridazine, haloperidol, sertindole, pimozide
• cisapride
• dronedarone
• droperidol
• intravenous erythromycin or pentamidine
• methadone
• moxifloxacin
• saquinavir.

References:

https://www.webmd.com/drugs/2/drug-11295/kytril-oral/details

https://www.netdoctor.co.uk/medicines/cancer-drugs/a6974/kytril-granisetron/

https://www.rxlist.com/kytril-drug.htm

https://www.drugs.com/kytril.html

https://www.medicinenet.com/granisetron-oral/article.htm

https://www.medbroadcast.com/drug/getdrug/kytril

https://www.accessdata.fda.gov/drugsatfda_docs/label/2009/020239s021,020305s014,021238s007lbl.pdf