This medication is used alone or with other medications to prevent nausea and vomiting caused by cancer drug treatment (chemotherapy). It is also used to prevent and treat nausea and vomiting after surgery in adults.
Granisetron works by blocking one of the body's natural substances (serotonin) that can cause vomiting.
Read the Patient Information Leaflet if available from your pharmacist before you start using granisetron and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
This drug is given into a vein as directed by your doctor, usually 30 minutes before cancer chemotherapy or before/during/after surgery. The drug may be given directly into a vein over 30 seconds, or it may be mixed in an IV fluid and given into a vein over a longer time (5 minutes).
If you are giving this medication to yourself at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.
Do not mix granisetron with other drugs in the same injection or inject other drugs into the same vein at the same time. If you have questions about using this medication properly, consult your pharmacist.
Dosage is based on your medical condition and response to treatment. The dosage may also be based on weight. Use this medication exactly as directed to get the most benefit from it. Do not use more medication or use it more often than prescribed. Ask your doctor or pharmacist if you have questions.
Tell your doctor if your nausea does not improve or if it worsens.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also taking other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you take (see Drug Interactions section). Get medical help right away if you develop some of the following symptoms: fast heartbeat, hallucinations, loss of coordination, severe dizziness, severe nausea/vomiting/diarrhea, twitching muscles, unexplained fever, unusual agitation/restlessness.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before using granisetron, tell your doctor or pharmacist if you are allergic to it; or to other anti-nausea serotonin blockers (e.g., dolasetron, ondansetron); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: stomach/intestinal problems (e.g., recent surgery, ileus, swelling).
This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.
Granisetron may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.
The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using granisetron, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).
Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using granisetron safely.
Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include: apomorphine.
Many drugs besides granisetron may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others.
The risk of serotonin syndrome/toxicity increases if you are also taking other drugs that increase serotonin. Examples include street drugs such as MDMA/"ecstasy," St. John's wort, certain antidepressants (including SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine), among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Tell your doctor if you miss your dose or did not use your dose at the correct time before your scheduled chemotherapy appointment or surgery. Your treatment or surgery may need to be rescheduled.
Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised July 2016. Copyright(c) 2016 First Databank, Inc.
With WebMD's Medicine Cabinet, you can check interactions with drugs.Go to medicine cabinet