Granisetron blocks the actions of chemicals in the body that can trigger nausea and vomiting.

Granisetron is used to prevent nausea and vomiting that may be caused by medicine to treat cancer (chemotherapy or radiation).

Granisetron may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Granisetron comes as a tablet 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 depending on the strength. 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.

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Granisetron is usually taken only on the day of treatment with chemotherapy or radiation.

Your doctor may want you to take only one dose, up to 1 hour before chemotherapy or radiation.

For patients undergoing chemotherapy, a second dose of granisetron is sometimes given 12 hours after the first dose. Follow your doctor's dosing instructions very carefully.

Do not share this medicine with another person.

Granisetron is not likely to be useful if you keep taking it during times when you are not receiving chemotherapy or radiation treatment.

Store at room temperature away from moisture, heat, and light.

You should not take granisetron if you are allergic to it.

To make sure granisetron is safe for you, tell your doctor if you have:

• heart disease;

• a heart rhythm disorder;

• a personal or family history of long QT syndrome;

• an electrolyte imbalance (such as low levels of potassium or magnesium in your blood); or

• if you have recently had stomach or intestinal surgery.

It is not known whether granisetron will harm an unborn baby. Tell your doctor if you are pregnant.

It is not known whether granisetron passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Granisetron is not approved for use by anyone younger than 18 years old.

Tell your doctor if you forget to take your dose within 1 hour before chemotherapy or radiation. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

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).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unless your doctor tells you otherwise, continue your normal diet.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Granisetron may cause serious side effects. Call your doctor at once if you have:

• headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;

• increased blood pressure--severe headache, buzzing in your ears, anxiety, confusion, shortness of breath; or

• high levels of serotonin in the body--agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting.

Common side effects of granisetron may include:

• headache, weakness;

• diarrhea, constipation;

• stomach pain, indigestion, loss of appetite;

• sleep problems (insomnia); or

• fever, flu symptoms.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Granisetron can cause a serious heart problem, especially if you use certain medicines at the same time, including antibiotics, antidepressants, heart rhythm medicine, antipsychotic medicines, and medicines to treat cancer, malaria, HIV or AIDS.

Taking granisetron together with certain other medicines can cause high levels of serotonin to build up in your body, a condition called "serotonin syndrome," which can be fatal. Tell your doctor if you also use:

• lithium;

• ritonavir;

• St. John's wort;

• an antidepressant;

• migraine headache medicine;

• a narcotic (opioid) medication or muscle relaxer; or

• other anti-nausea medications.

This list is not complete. Other drugs may interact with granisetron, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using during your treatment with granisetron.

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.