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Granisetron

Granisetron is used to treat and prevent nausea and vomiting. Learn how to use the medication, its common side effects, special precautions to watch out for, and more.
  • Article last reviewed 26 November 2025
  • 5 mins read

What is this medication for?

This medication is used to treat and prevent nausea and vomiting.

This includes nausea and vomiting associated with drugs used to treat cancer, radiotherapy and also after surgery.

How should I take or use this medication?

When taken by mouth, you may take this medication with or without food.

A healthcare professional would administer this medication by injection if applicable.

What should I do if I forget to take or use this medication?

If you forget to take a dose, take it as soon as you remember. Then take your next dose at the usual time. Do not take two doses to make up for the missed dose.

What precautions should I take when taking or using this medication?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, planning to become pregnant, or are breastfeeding.
  • You are taking other medications, including supplements, traditional medications and herbal remedies.
  • You have a history of an abnormal heart rhythm or heart rate.
  • You have galactose intolerance, total lactase deficiency or glucose-galactose malabsorption. Some preparations contain lactose.
  • You have a history of a blockade in your gut or chronic constipation.

What are some common side effects of this medication? ​

  • Common side effects include difficulty sleeping (insomnia), headaches and constipation.

What are some rare but serious side-effects that I need to seek medical advice immediately? 

The symptoms of a drug allergy include one or more of the following:

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

The medication may rarely cause a condition called Serotonin Syndrome, particularly if used concurrently with other medications which cause the same condition. Symptoms may include an altered mental state, excessive sweating, fever, altered heart rate / blood pressure, rigidity and incoordination.

This medication may alter your heart rhythm / rate.

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take or use this medication?

This medication may reduce your blood pressure when used together with apomorphine which is also used to treat nausea and vomiting.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How do I throw away this medication safely? ​

For general waste: pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.

Disclaimer

Please take note that the above is not a complete list of all possible side-effects. If you have any concerns about your medication or if you have other side-effects that you think are caused by this medication, please consult your doctor or pharmacist. If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (NHG Health, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.