Belzutifan (Welireg)

The Basics

Belzutifan (brand name – Welireg) is an FDA-approved treatment for kidney, pancreas, brain, and spinal cord cancers. It is also used for the treatment of von Hippel-Lindau disease (VHL; a rare disease that causes tumours in various parts of the body. It is generally used in adults. The use of Belzutifan in children is still under consideration.

Belzutifan is in a class of medications called hypoxia-inducible factor inhibitors. It works by blocking the activity of a certain protein. Thus, it helps by reducing or stopping the growth of tumour cells.

Let us walk you through all the key things you need to know about Belzutifan.

Make sure you read IMPORTANT WARNING section at the end of this article.

How should I take belzutifan (Welireg)?

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Belzutifan comes as a tablet to take by mouth. It is usually taken once daily with or without food. Take belzutifan at around the same time every day.

Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take belzutifan exactly as directed. Do not take more or less of it or more often than your doctor prescribes.

Swallow the tablets whole; do not split, chew, or crush them. If you vomit after taking belzutifan, do not take another dose. Continue your regular dosing schedule on the next day.

Do not stop taking belzutifan without talking to your doctor. You can help them by tracking your side effects in Ankr.

What are the side effects of belzutifan or Welireg?

Serious side effects

Belzutifan may cause other side effects. Call your doctor if you have any unusual problems while taking this medication. If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online or by phone (1-800-332-1088).

Use the free Ankr platform or Ankr app to track your symptoms.

What special precautions should I follow?

Before taking Belzutifan or Welireg

  • tell your doctor about your allergies
  • tell your doctor about other intakes
  • tell your doctor if you have or have ever had any other disease or symptom in the past or now

While you are on belzutifan or Welireg

  • if you become pregnant while taking belzutifan call your doctor immediately. It may harm the fetus.
  • tell your doctor if you are breastfeeding. You should not breast-feed while you are taking belzutifan and for 1 week after your final dose.
  • you should know that this medication may decrease fertility in men and women.

I forgot a dose. What should I do?

Take the missed dose as soon as you remember it on the same day, then continue your regular dosing schedule the next day. Do not take a double dose to make up for a missed.

In case of an emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

How should I safely store and dispose of belzutifan or Welireg?

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).

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.

You can dispose of unneeded medications 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 ( for more information if you do not have access to a take-back program.

What special dietary instructions should I follow?

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

Brand names

  • Welireg®

Last Revised – 03/05/2023, FDA update – 08/13/2021, SG

Do not take belzutifan if you are pregnant, plan to become pregnant, or plan to father a child. You will have to take a pregnancy test before starting treatment. If you are female, you will need to use non-hormonal birth control during your treatment and for 1 week after your final dose. Belzutifan may interfere with the action of hormonal contraceptives (birth control pills, patches, rings, implants, or injections), so you should not use these as your only method of birth control during your treatment. If you are male, you and your female partner should use birth control during your treatment and continue to use birth control for 1 week after your final dose. Ask your doctor to help you choose a method of birth control that will work for you or your partner. Belzutifan may harm the fetus.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with belzutifan and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website ( or the manufacturer’s website to obtain the Medication Guide.

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DISCLAIMER: No part of this content constitutes medical advice, opinion, or should be used for medical decision making without consultation with a licenced medical practitioner and under a patient-provider relationship. All information on the website is provided without any claims of accuracy. For full terms and conditions, visit this link. Content curated by the Ankr team.

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