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Generic name: venetoclax [ ven-ET-oh-klax ]
Brand names: Venclexta, Venclexta Starting Pack
Dosage forms: oral kit (10 mg-50 mg-100 mg), oral tablet (10 mg; 100 mg; 50 mg)
Drug class: Miscellaneous antineoplastics

Medically reviewed by on Jun 4, 2021. Written by Cerner Multum.

What is venetoclax?

Venetoclax is used to treat chronic lymphocytic leukemia or small lymphocytic leukemia in adults.

Venetoclax is also used in combination with other medicines to treat acute myeloid leukemia in adults who are 75 years or older, or who cannot use standard chemotherapy due to other medical conditions.

Venetoclax may also be used for purposes not listed in this medication guide.


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

Some drugs should not be used with venetoclax. Your treatment plan may change if you also 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; or

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

May harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant. Use birth control while using venetoclax 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 venetoclax.

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

How should I take venetoclax?

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.

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

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

If you vomit shortly after taking venetoclax, 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 venetoclax. Also drink 6 to 8 glasses of water on the day you first take venetoclax, 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 venetoclax without first asking your doctor.

Store tablets in their original container at room temperature, away from moisture and heat. Do not put venetoclax 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 venetoclax?

Avoid receiving a "live" vaccine. The vaccine may not work as well while you are using venetoclax. 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.

Venetoclax side effects

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

Venetoclax may cause serious side effects. Call your doctor at once if you have:

  • symptoms of sepsis--confusion, severe drowsiness, rapid breathing, feeling very ill;

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

  • low blood cell counts--fever, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed; or

  • signs of tumor cell breakdown--chills, joint or muscle pain, feeling tired or short of breath, fast or slow heartbeats, 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 side effects of venetoclax may include:

  • stomach pain, nausea, vomiting, diarrhea, constipation;

  • feeling tired or short of breath;

  • low blood pressure, feeling dizzy or lightheaded;

  • muscle and joint pain;

  • swelling in your arms, legs, hands, and feet;

  • fever, low blood cell counts;

  • pneumonia, sepsis;

  • mouth pain;

  • rash; or

  • cold symptoms such as stuffy nose, sneezing, sore throat, cough.

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 venetoclax?

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 affect 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 this medication only for the indication prescribed.

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