This medication is used to prevent nausea and vomiting due to cancer drug treatment (chemotherapy) and radiation therapy. It works by blocking one of the body's chemicals (serotonin) that causes vomiting.
Take this medication by mouth. It is important to follow your doctor's instructions for the timing of each dose. If you have any questions, consult your doctor or pharmacist.
Inform your doctor if your condition persists or worsens.
Diarrhea, constipation, stomach pain, weakness, headache, fever, dizziness, drowsiness, trouble sleeping, and anxiety may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
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.
Tell your doctor immediately if this highly unlikely but very serious side effect occurs: unusual muscle movements or stiffness.
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 serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: 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.
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 taking granisetron, tell your doctor or pharmacist if you are allergic to it; 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.
This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.
Granisetron may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can infrequently result in 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).
This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.
This drug should not be used with the following medication because a very serious interaction may occur: apomorphine.
If you are currently using the medication listed above, tell your doctor or pharmacist before starting granisetron.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use.
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.
Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
If overdose is suspected, contact a poison control center or emergency room immediately. 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.
It is important that each dose is taken according to the prescribed schedule. If you miss a dose, contact your doctor or pharmacist immediately to establish a new dosing schedule.
For oral tablets: Store at room temperature between 59-86 degrees F (15-30 degrees C).
For oral solution: Store at room temperature at 77 degrees F (25 degrees C). Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Store bottle in an upright position.
Store away from light and moisture. Do not store in the bathroom. Keep all medicines 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 for more details about how to safely discard your product.
Information last revised November 2014. Copyright(c) 2014 First Databank, Inc.
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