Venetoclax is used alone or in combination with obinutuzumab (Gazyva) or rituximab (Rituxan) to treat certain types of chronic lymphocytic leukemia (CLL; a type of cancer that begins in the white blood cells) or certain types of small lymphocytic lymphoma (SLL; a type of cancer that begins mostly in the lymph nodes). It is also used in combination with either azacitidine (Vidaza), decitabine (Dacogen), or cytarabine as a first treatment for acute myeloid leukemia (AML; a type of cancer that begins in the white blood cells) in people 75 years of age or older, or in adults who have medical conditions that prevents them from being treated with other chemotherapy medications. Venetoclax is in a class of medications called B-cell lymphoma-2 (BCL-2) inhibitors. It works by blocking the action of a certain protein in the body that helps cancer cells survive. This helps to kill cancer cells.

Side Effects Of Venetoclax

Venetoclax may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • diarrhea
  • constipation
  • nausea
  • vomiting
  • decreased appetite
  • extreme tiredness
  • swelling of your arms or hands
  • back pain
  • bone, muscle, or joint pain
  • abdominal pain
  • swelling or sores in the mouth
  • mouth or throat pain
  • headache
  • runny or stuffy nose, cough
  • shortness of breath
  • dizziness
  • rash
  • difficulty falling asleep or staying asleep

Some side effects can be serious. If you experience any of these symptoms or those listed in the WARNINGS and PRECAUTIONS section, call your doctor immediately:

  • fever alone or along with sore throat, cough, chills, warm, red, painful or swollen skin, urgent, frequent, or painful urination, and other signs of infection
  • decreased urination
  • swelling of your legs, ankles, or feet
  • unusual or heavy bleeding or bruising
  • pale skin, shortness of breath, dizziness, extreme tiredness, fast heartbeat

Venetoclax may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before taking venetoclax:

  • tell your doctor and pharmacist if you are allergic to venetoclax, any other medications, or any of the ingredients in venetoclax tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor if you are taking clarithromycin, conivaptan (Vaprisol), indinavir (Crixivan), itraconazole (Onmel, Sporanox), ketoconazole, lopinavir (in Kaletra), posaconazole (Noxafil), ritonavir (Norvir, in Kaletra, Technivie, Viekira Pak), or voriconazole (Vfend). Your doctor may tell you not to take venetoclax if you are taking one or more of these medications.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: amiodarone (Nexterone, Pacerone), bosentan (Tracleer), captopril, carbamazepine (Carbatrol, Epitol, Equetro, Tegretol, Teril), carvedilol (Coreg), ciprofloxacin (Cipro), cyclosporine (Gengraf, Neoral, Sandimmune), digoxin (Lanoxin), diltiazem (Cardizem, Cartia XT, Diltzac, Taztia, Tiazac), dronedarone (Multaq), efavirenz (Sustiva, in Atripla), erythromycin (E.E.S., Eryc, Eryped, Ery-tab, Erythrocin), etravirine (Intelence), everolimus (Afinitor, Zortress), felodipine, fluconazole (Diflucan), modafinil (Nuvigil, Provigil), nafcillin (Nallpen), phenytoin (Dilantin, Phenytek), quinidine (in Nuedexta), ranolazine (Ranexa), rifampin (Rifadin, Rimactane, in Rifamate, Rifater), sirolimus (Rapamune), ticagrelor (Brilinta), verapamil (Calan, Verelan, in Tarka), or warfarin (Coumadin, Jantoven). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with venetoclax, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor what herbal products you are taking, especially quercetin or St. John’s wort.
  • tell your doctor if you have or have ever had problems with your levels of potassium, phosphorus, or calcium in your blood; high levels of uric acid in your blood; gout (a type of arthritis caused by crystals deposited in the joints); or kidney or liver disease.
  • tell your doctor if you are pregnant or plan to become pregnant. If you can become pregnant, you will need to have a pregnancy test before beginning treatment with venetoclax. You should not become pregnant during your treatment and for 30 days after your final dose. Talk to your doctor about birth control methods that you can use during your treatment. If you become pregnant while taking venetoclax, call your doctor.
  • tell your doctor if you are breastfeeding. Do not breastfeed while taking venetoclax.
  • you should know that this medication may decrease fertility in men. Talk to your doctor about the risks of taking venetoclax.
  • do not have any vaccinations before, during, or after treatment with venetoclax without talking to your doctor.
  • you should know that you may experience tumor lysis syndrome (TLS; a condition caused by the fast breakdown of cancer cells that can cause kidney failure and other complications) during your treatment with venetoclax. This is more likely to happen when you are first starting treatment, and each time your dose is increased. To help reduce your risk of experiencing TLS you should drink at least 6 to 8 glasses (48 to 64 ounces) of water a day for 2 days before and on the day of your first dose, and each time your dose is increased. In addition your doctor will give you a medication to take before starting and during your treatment to help prevent this side effect. If you experience any of the following symptoms of TLS call your doctor immediately: fever, chills, nausea, vomiting, confusion, shortness of breath, seizures, irregular heartbeat, dark or cloudy urine, unusual tiredness, or muscle or joint pain.

Dosage Of Venetoclax

Venetoclax comes as a tablet to take by mouth. It is usually taken with a meal and water once a day. Take venetoclax 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 venetoclax exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

If you vomit after taking venetoclax, do not repeat the dose. Continue your regular dosing schedule.

Your doctor will probably start you on a low dose of venetoclax and gradually increase your dose, not more than once every week for the first 5 weeks if you are being treated for CLL or SLL, and once a day for the first 3 or 4 days if you are being treated for AML.

Your doctor may need to interrupt or stop your treatment if you experience certain side effects. Be sure to tell your doctor how you are feeling during your treatment with venetoclax. For certain side effects, your doctor may tell you to start taking venetoclax at a lower dose.


Consult your doctor or pharmacist


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.