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Generic Name: venetoclax (ven ET oh klax)
Brand Name: Venclexta

Medically reviewed by Philip Thornton, DipPharm. Last updated on Dec 1, 2020.

What is Venclexta?

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

Venclexta is also used in combination with azacitidine, decitabine, or 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.


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.

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.

Before taking this medicine

You should not use Venclexta if you are allergic to venetoclax.

Some medicines can cause unwanted or dangerous effects when used with Venclexta. Your doctor may need to change your treatment plan if you also use:

Tell your doctor about all medicines you use. Do not start or stop using any medicine without asking your doctor.

Tell your doctor if you have ever had:

  • liver or kidney disease;

  • an electrolyte imbalance (such as low levels of potassium or calcium in your blood);

  • gout, or high levels of uric acid in your blood;

  • if you use a blood thinner (such as warfarin) and you have routine "INR" or prothrombin time tests; or

  • if you are scheduled to receive any vaccine.

You may need to have a negative pregnancy test before starting this treatment.

Do not use Venclexta if you are pregnant. It could harm the unborn baby or cause birth defects. Tell your doctor right away if you become pregnant while taking Venclexta. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 30 days after your last dose.

This medicine may affect fertility (ability to have children) in men. Talk to your doctor if you are concerned about this risk.

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. Use the medicine exactly as directed.

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

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

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

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

If you vomit shortly after taking Venclexta, do not take another tablet. Wait until the next day to take your medicine at the scheduled time.

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 Venclexta, and whenever your dose is changed.

Venetoclax can lower your blood cell counts. Your blood will need to be tested often. Your cancer treatments may be delayed based on the results of these tests.

Do not stop using Venclexta without first asking your doctor.

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

Dosing information

Usual Adult Dose for Chronic Lymphocytic Leukemia:

-Initial Dose:
Weekly Ramp-Up Schedule Over 5 Weeks:
Week 1: 20 mg orally once a day
Week 2: 50 mg orally once a day
Week 3: 100 mg orally once a day
Week 4: 200 mg orally once a day
Week 5: 400 mg orally once a day

-Maintenance Dose: 400 mg orally once a day
-Duration of Therapy: Until disease progression or unacceptable toxicity is observed.

-Select patients based on the presence of 17p deletions in blood specimens, as detected by an approved test.
-Retest patients without 17p deletion at relapse as acquisition of 17p deletion can occur.

Use: Treatment of patients with chronic lymphocytic leukemia (CLL) with 17P deletion who have received at least one prior therapy.

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 to avoid

Do not receive a "live" vaccine while using Venclexta. The vaccine may not work as well during this time, and may not fully protect you from disease. Live vaccines include measles, mumps, rubella (MMR), polio, rotavirus, typhoid, yellow fever, varicella (chickenpox), and zoster (shingles).

Grapefruit and Seville oranges may interact with venetoclax and lead to unwanted side effects. Avoid the use of grapefruit products 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:

  • signs of pneumonia - cough with yellow or green mucus, stabbing chest pain, wheezing, trouble breathing;

  • low blood cell counts - fever, chills, flu-like symptoms, swollen gums, mouth sores, skin sores, pale or yellowed skin, dark colored urine, confusion or weakness; or

  • signs of tumor cell breakdown - fever, chills, joint or muscle pain, feeling tired or short of breath, fast or slow heartbeats, confusion, nausea, vomiting, dark or cloudy urine, or seizure (convulsions).

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 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

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 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

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

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.