Granisetron is used to prevent nausea and vomiting caused by cancer chemotherapy and radiation therapy. Granisetron is in a class of medications called 5-HT3antagonists. It works by blocking serotonin, a natural substance in the body that causes nausea and vomiting.
Granisetron comes as a tablet and a solution (liquid) to take by mouth. When taken to prevent nausea and vomiting caused by chemotherapy, granisetron is usually taken 1 hour before chemotherapy is begun. A second dose may be taken 12 hours after the first dose. When taken to prevent nausea and vomiting caused by radiation, granisetron is usually taken within 1 hour before treatment. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take granisetron exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking granisetron,
- tell your doctor and pharmacist if you are allergic to granisetron, dolasetron (Anzemet), ondansetron, (Zofran), or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention ketoconazole (Nizoral). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking granisetron, call your doctor.
Unless your doctor tells you otherwise, continue your normal diet.
Granisetron should only be taken before chemotherapy or radiation therapy, as instructed by your doctor. It should not be taken on a regularly scheduled basis.
Granisetron may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- stomach pain
- difficulty falling asleep or staying asleep
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:
- skin rash
- difficulty breathing or swallowing
- blurred vision
Granisetron may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
Keep all appointments with your doctor.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: September 1, 2010.