Medication Information Leaflet

What is this medication for?

Venetoclax is mainly used to treat acute myeloid leukemia and chronic lymphocytic leukemia, which are cancers that affect the blood cells. It works by binding to a protein called B-cell lymphoma 2 (Bcl-2), blocking its action and allowing the cancer cells to starve and die off.

How should I take/use this medication?

This medication should be taken after food at approximately the same time each day. You should swallow the tablet whole with water. Do not chew, crush, or break the tablets prior to swallowing.

Do not stop taking your medication without checking with your healthcare professional.

If possible, handle the medication yourself. If a family member or caregiver needs to give the medication, do wash their hands before and after handling the medication.

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

If you forget to take a dose and it is within 8 hours of the usual time, take it as soon as you remember and continue your usual daily dose the next day.

If it is more than 8 hours, do not take the missed dose and continue your usual daily dose the next day. Do not take two doses to make up for the missed dose.

If you vomit after taking a dose, do not take a second dose. Continue your usual daily dose the next day.

What precautions should I take?

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 breastfeeding
    • This medication may cause harm to an unborn child. You are advised to practice strict birth control when taking the medication and at least 30 days after stopping the medication
    • This medication may pass into breast milk and harm your baby. Do not breastfeed when taking the medication and for at least 1 week after stopping the medication
  • You have a history of high uric acid levels or gout
  • You are taking any other medications including supplements, traditional medications and herbal remedies

What are some common side-effects of this medication?

  • Temporary decrease in blood cell counts
    • This may put you at higher risk of infections, bleeding or bruising and feeling tired
    • Reduce your risk of getting an infection by:
      • Maintaining good hand hygiene. Wash your hands often during the day especially before you eat or after using the toilet
      • Avoid crowded spaces and wear a mask to protect yourself
      • Eating freshly cooked food. Avoid raw meats, vegetables, eggs, half-cooked or uncooked food
    • Brush teeth gently with a soft bristle toothbrush to prevent gum bleeding
    • Be careful when handling sharp objects such as scissors or knives
  • Loose and frequent stools (diarrhoea)
    • Reduce consumption of foods high in fibre such as raw fruits and vegetables which cause softer and more frequent stools
    • Have foods such as porridge or soups which are gentler on the stomach
    • Ensure you are drinking sufficient fluids (at least 2 litres or 8 cups of water or fluids a day)
    • Avoid spicy and/or fried food
    • Avoid alcohol
    • Avoid coffee, tea, milk and dairy products.
    • Take antidiarrheal medicine as instructed to manage your diarrhoea. Inform your doctor if the antidiarrhoeal medicine does not help with your diarrhoea.
  • Hard stools (constipation)
    • Increase your fibre intake by taking at least 2 servings of fruits and vegetables daily
    • Ensure you are drinking sufficient fluid
    • Increasing your daily activity may also help to relieve constipation
  • Feeling tired or weak
    • Try to pace yourself and plan your day ahead so you have time to rest
    • Engage in light exercises such as taking a short walk to stay healthy
  • Muscle pain
    • Avoid intense physical exercises to prevent it from getting worse
  • Mouth ulcers
    • Maintain good oral hygiene by brushing your teeth twice a day with a soft toothbrush
    • Avoid foods and drinks that are too hot or spicy
  • Tumor lysis syndrome
    • This condition is caused by a fast breakdown of cancer cells
    • Reduce your risk by drinking 6 to 8 glasses of water each day, starting 2 days before your first dose.
    • Inform your doctor immediately if you experience any unusually fast heartbeat, muscle weakness or cramps or pain, dark and cloudy urine, unusual tiredness or seizures
  • Swelling of lower legs or hands
    • If your hands or arms are swollen, hold them above your heart level to bring down the swelling
    • Raise your legs at night by placing a pillow underneath the legs

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

Other serious side effects include:

  • Infections
    • Signs of infection include:
      • Fever (temperature over 38°C)
      • Chills
      • Severe sore throat
      • Cough with thick or green phlegm
      • Cloudy or foul smelling urine
      • Painful, tender, or swollen red skin wounds or sores
  • Unusual bleeding
    • Signs of unusual bleeding include:
      • Bruising without a cause or bruises that worsen
      • Dark (black or red), sticky stools
      • Coughing out blood
      • Vomit that looks like coffee grounds
      • Passing blood in the urine
      • Prolonged bleeding

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 this medication?

Avoid taking grapefruit, starfruit, pomelo, pomegranate when you are taking this medicine as these fruits may interact with your medicine and increase the risk of side-effects.

Many drugs may interact with Venetoclax. Check with your doctor or pharmacist before you start or stop any other drugs.

How should I store this medication?

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

How should I throw away this medication safely?

Pack the medication into a bag and bring it back to the pharmacy where you received the medication from.


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 (National Healthcare Group, 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.

Last updated on Aug 2023

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