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Generic name: venetoclaxven-ET-oh-klax ]
Brand names: Venclexta, Venclexta Starting Pack
Drug class: Miscellaneous antineoplastics

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 23, 2023.

What is Venclexta?

Venclexta inhibits a certain protein in cancer cells (abnormal lymphocytes produced in chronic lymphocytic leukemia) that helps keep those cells alive and makes them resistant to chemotherapy. Venetoclax binds to this protein, which helps kill the cancerous lymphocytes in blood and bone marrow.

Venclexta is a prescription medicine used to treat chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL) in adults with or without 17p deletion (a specific genetic marker). Venetoclax is sometimes used in combination with rituximab to treat these conditions.

Venclexta is also used in combination with azacitidine, decitabine, or low-dose cytarabine to treat acute myeloid leukemia.This combination is for use in adults who are 75 years or older, or who cannot use standard chemotherapy due to other medical conditions.


Call your doctor at once if you have a fever, chills, joint or muscle pain, tiredness, confusion, shortness of breath, fast or slow heartbeats, nausea, vomiting, dark or cloudy urine, or a seizure (convulsions).

Drink 6 to 8 full glasses of water each day to help prevent these side effects.

Tell your doctor about all your current medicines and any you start or stop using. Many drugs can interact, and some drugs should not be used together.

Before taking this medicine

Some drugs should not be used with Venclexta. Your treatment plan may change if you also use:

Do not start or stop using any medicine without asking your doctor.

To make sure Venclexta is safe for you, tell your doctor if you have ever had:

May harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant. Use birth control while using Venclexta and for at least 30 days after your last dose. Tell your doctor if you become pregnant.

It may be harder for a man to get a woman pregnant while you using this medicine.

You should not breastfeed while using this medicine and for at least 1 week after your last dose.

How should I take Venclexta?

Take Venclexta exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You may receive your first dose in a hospital or clinic setting to quickly treat any serious side effects.

Take Venclexta with food and water, at the same time each day.

Do not crush, chew, or break a tablet. Swallow the tablet whole.

If you vomit shortly after taking Venclexta, do not take another tablet. Take your next dose as scheduled the next day.

To prevent certain side effects, drink 6 to 8 glasses of water daily for 2 days before you start taking Venclexta. Also drink 6 to 8 glasses of water on the day you first take this medicine, and whenever your dose is changed.

You may need frequent medical tests and your cancer treatments may be delayed based on the results.

Do not stop using this medicine without first asking your doctor.

Store tablets in their original container at room temperature, away from moisture and heat. Do not put the tablets into a daily pill box.

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if you are more than 8 hours late for the dose. Do not use two doses at one time.

What happens if I overdose?

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

What should I avoid while taking Venclexta?

Avoid receiving a "live" vaccine. The vaccine may not work as well while you are using Venclexta. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), and zoster (shingles).

Grapefruit, starfruit, and Seville oranges may interact with venetoclax and lead to unwanted side effects. Avoid consuming grapefruit products, starfruit, and orange marmalades.

Venclexta side effects

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

Call your doctor at once if you have:

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common Venclexta side effects may include:

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.

What other drugs will affect Venclexta?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can interact with venetoclax. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.

Popular FAQ

Venclexta (venetoclax) is a targeted treatment rather than a type of chemotherapy. Chemotherapy is defined as a drug treatment that kills fast-growing cells in your body. Venclexta works by binding to a specific protein called BCL-2 which is overexpressed on cancerous cells in people with cancers such as AML and CLL. By binding to this protein Venclexta kills cancerous CLL and AML lymphocytes, in preference to other fast-growing cells. Continue reading

Venclexta (venetoclax) is effective for both CLL and AML with trials reporting significantly more people experiencing complete remission with Venclexta in combination with other treatments compared to standard therapy. Venclexta works quickly as well, with it taking an average of one month for many people to experience a reduction in disease progression. Continue reading

Venclexta is usually taken for 12 months by previously untreated patients with CLL or SLL and for 24 months for previously treated patients with CLL or SLL. For patients with AML, Venclexta is taken for as long as it is deemed safe to do so (until disease progression or unacceptable toxicity is observed). Continue reading

Although Venclexta is not FDA approved to treat MM, a subgroup analysis of the BELLINI clinical trial, which was halted early by the FDA due to safety concerns, revealed that Venclexta in combination with other treatments may be beneficial for those with relapsed or refractory MM bearing the t(11;14) translocation or with high levels of BCL-2. Continue reading

Venclexta is given once-daily with food in combination with either azacytidine, decitabine, or low-dose cytarabine in adults with AML. It works by binding to a specific protein that is over-expressed in cancerous lymphocytes, killing them. Continue reading

Vencelxta works by binding directly to a protein called BCL-2, which is overexpressed on some cancer cells. When Vencelxta binds to BCL-2 it displaces other proteins, such as BIM, which help to activate the process of apoptosis, which leads to the death of the cells. Continue reading

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Venclexta only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.