Granisetron: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing

Uses

What is granisetron used for?

Granisetron is commonly used to prevent nausea and vomiting that can happen when using medicines for cancer or radiation therapy.

Granisetron may also be used for other conditions as determined by your healthcare provider.

How does granisetron work (mechanism of action)?

Granisetron blocks a specific receptor in the gut (intestines) and brain called 5-HT₃ that normally causes nausea when your body is exposed to certain substances or other triggers, such as radiation. By blocking this receptor, granisetron reduces nausea caused by chemotherapy and radiation treatment.

How is granisetron supplied (dosage forms)?

Granisetron is available as 1 mg oral tablets that are taken by mouth.

Granisetron is also available in injectable forms.

How should I store granisetron?

Granisetron should be stored at room temperature between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place. Protect from light.

Side Effects

What are the most common side effects of granisetron?

The most common side effects of granisetron are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

Headache
Constipation/diarrhea
Weakness/lack of energy
Stomach pain/indigestion

There may be other side effects of granisetron that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of granisetron?

While less common, the most serious side effects of granisetron are described below, along with what to do if they happen.

Severe Allergic Reactions. Granisetron may cause allergic reactions, which can be serious. Stop using granisetron and get help right away if you have any of the following symptoms of a serious allergic reaction.

Breathing problems or wheezing
Racing heart
Fever or general ill feeling
Swollen lymph nodes
Swelling of the face, lips, mouth, tongue, or throat
Trouble swallowing or throat tightness
Itching, skin rash, or pale red bumps on the skin called hives
Nausea or vomiting
Dizziness, feeling lightheaded, or fainting
Stomach cramps
Joint pain

Heart Rhythm Changes. Granisetron may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take some medicines for other heart rhythm problems. Tell your healthcare provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

Serotonin Syndrome. Serotonin syndrome is when there is too much of a substance called serotonin in your body. Granisetron can cause serotonin syndrome when it is taken alone or with other medicines that affect serotonin (see Interactions). This condition can be life-threatening. Get emergency help if you have any of the following symptoms of serotonin syndrome.

Sweating, fever, or flushing
Confusion
Feeling agitated or restless
Seeing or hearing unusual things
Dizziness
Fast or racing heartbeat
Nausea, vomiting, or diarrhea
Muscle twitching, stiffness, or tremor
Seizures

Warnings & Precautions

Who should not use granisetron?

Allergies to Ingredients. People who are allergic to any of the following should not use/take granisetron.

Granisetron
Sancuso
Sustol
Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific granisetron products they stock.

What should I know about granisetron before using it?

Do not take granisetron unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share granisetron with other people, even if they have the same condition as you. It may harm them.

Keep granisetron out of the reach of children.

What should I tell my healthcare provider before using granisetron?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if granisetron is right for you.

Abdominal Surgery. Tell your healthcare provider if you have had recent surgery on your gut (stomach or intestines). In this case, as granisetron prevents nausea and vomiting, it may be more difficult to determine if you are having complications from your surgery, such as any blockage, for example.

Pregnancy. It is not known if or how granisetron could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. It is not known if granisetron passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does granisetron interact with foods or drinks?

There are no known interactions between granisetron and foods or drinks.

It is unknown if drinking alcohol will affect granisetron.

Does granisetron interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using granisetron.

Medicines [within the past 2 weeks] that can cause QT prolongation, which is a potentially dangerous heart rhythm problem
A selective serotonin reuptake inhibitor (SSRI), which is a medicine commonly used for anxiety and depression
A serotonin norepinephrine reuptake inhibitor (SNRI), which is a medicine commonly used for anxiety and depression
A type of medicine called a triptan, such as sumatriptan (Imitrex and others), eletriptan (Relpax), and others, which is commonly used to treat migraines

This may not be a complete list of medicines that can interact with granisetron. Always check with your healthcare provider.

Does Granisetron interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much granisetron?

If you or someone else has used too much granisetron, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of granisetron?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.