Venetoclax (Venclexta™)

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About This Drug

Venetoclax is used to treat cancer. It is given orally (by mouth).

Possible Side Effects

  • Bone marrow suppression. This is a decrease in the number of white blood cells, red blood cells, and platelets. This may raise your risk of infection, make you tired and weak (fatigue), and raise your risk of bleeding.
  • Nausea and vomiting
  • Diarrhea (loose bowel movements)
  • Constipation (not able to move bowels)
  • Pain in your mouth/throat
  • Pain in your abdomen
  • Abnormal bleeding – symptoms may be coughing up blood, throwing up blood (may look like coffee grounds), red or black tarry bowel movements, abnormally heavy menstrual flow, nosebleeds or any other unusual bleeding
  • Fever and fever in the setting of decreased white blood cells, which is a serious condition that can be life-threatening
  • Tiredness
  • Feeling dizzy
  • Upper respiratory infection
  • Cough
  • Trouble breathing
  • Infections, including bacterial infection in the blood
  • Bone and muscle pain
  • Back pain
  • Swelling of your legs, ankles and/or feet
  • Rash
  • Low blood pressure

Note: Each of the side effects above was reported in 20% or greater of patients treated with venetoclax. Not all possible side effects are included above.

Warnings and Precautions

  • Tumor lysis syndrome: This drug may act on the cancer cells very quickly. This may affect how your kidneys work and can be life-threatening.
  • Severe decrease in the number of white blood cells. This may raise your risk of infection.
  • Severe infections, including viral, bacterial and fungal, which can be life-threatening

Note: Some of the side effects above are very rare. If you have concerns and/or questions, please discuss them with your medical team.

Important Information

  • Talk to your doctor before receiving any vaccinations during your treatment. Some vaccinations are not recommended while receiving venetoclax.

How to Take Your Medication

  • Swallow the medicine whole with food and water at approximately the same time each day. Do not chew, break, cut or crush it.
  • Missed dose: If you have missed your dose by more than 8 hours, skip the missed dose and continue with your regular dosing schedule, and contact your physician. If you have missed a dose and it is within 8 hours of the time you usually take your dose, take the missed dose as soon as possible and then continue with your regular dosing schedule.
  • If you vomit a dose, take your next dose at the regular time. Do not take 2 doses at the same time or extra doses.
  • Handling: Wash your hands after handling your medicine. Your caretakers should not handle your medicine with bare hands and should wear latex gloves.
  • This drug may be present in the saliva, tears, sweat, urine, stool, vomit, semen, and vaginal secretions. Talk to your doctor and/or your nurse about the necessary precautions to take during this time.
  • Storage: Store this medicine in the original container at room temperature.
  • Disposal of unused medicine: Do not flush any expired and/or unused medicine down the toilet or drain unless you are specifically instructed to do so on the medication label. Some facilities have take-back programs and/or other options. If you do not have a take-back program in your area, then please discuss with your nurse or your doctor how to dispose of unused medicine.

Treating Side Effects

  • Manage tiredness by pacing your activities for the day.
  • Be sure to include periods of rest between energy-draining activities.
  • If you are dizzy, get up slowly after sitting or lying.
  • To decrease the risk of infection, wash your hands regularly.
  • Avoid close contact with people who have a cold, the flu, or other infections.
  • Take your temperature as your doctor or nurse tells you, and whenever you feel like you may have a fever.
  • To help decrease the risk of bleeding, use a soft toothbrush. Check with your nurse before using dental floss.
  • Be very careful when using knives or tools.
  • Use an electric shaver instead of a razor.
  • Drink plenty of fluids (a minimum of eight glasses per day is recommended).
  • If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack of water in the body from losing too much fluid).
  • If you have diarrhea, eat low-fiber foods that are high in protein and calories and avoid foods that can irritate your digestive tracts or lead to cramping.
  • If you are not able to move your bowels, check with your doctor or nurse before you use enemas, laxatives, or suppositories.
  • Ask your nurse or doctor about medicine that can lessen or stop your diarrhea and/or constipation.
  • To help with nausea, eat small, frequent meals instead of three large meals a day. Choose foods and drinks that are at room temperature. Ask your nurse or doctor about other helpful tips and medicine that is available to help stop or lessen these symptoms.
  • Get regular exercise. If you feel too tired to exercise vigorously, try taking a short walk. 
  • Keeping your pain under control is important to your well-being. Please tell your doctor or nurse if you are experiencing pain.
  • If you get a rash do not put anything on it unless your doctor or nurse says you may. Keep the area around the rash clean and dry. Ask your doctor for medicine if your rash bothers you.

Food and Drug Interactions

  • Avoid grapefruit products, Seville oranges, and starfruit while taking this medicine. These foods may raise the levels of venetoclax in your body. This could make side effects worse.
  • Check with your doctor or pharmacist about all other prescription medicines and over-the-counter medicines and dietary supplements (vitamins, minerals, herbs and others) you are taking before starting this medicine as there are known drug interactions with venetoclax. Also, check with your doctor or pharmacist before starting any new prescription or over-the-counter medicines, or dietary supplements to make sure that there are no interactions.
  • Avoid the use of St. John’s Wort while taking venetoclax as this may lower the levels of the drug in your body, which can make it less effective.
  • There are known interactions of venetoclax with blood thinning medicine such as warfarin. Ask your doctor what precautions you should take.

When to Call the Doctor

Call your doctor or nurse if you have any of these symptoms and/or any new or unusual symptoms:

  • Fever of 100.4° F (38° C) or higher
  • Chills
  • Tiredness that interferes with your daily activities
  • Feeling dizzy or lightheaded
  • Easy bleeding or bruising
  • Blood in your urine, vomit (bright red or coffee-ground) and/or stools (bright red, or black/tarry)
  • Coughing up blood
  • Wheezing or trouble breathing
  • Coughing yellow, green, or bloody mucus
  • Nausea that stops you from eating or drinking and/or is not relieved by prescribed medicines
  • Throwing up more than 3 times a day
  • Diarrhea, 4 times in one day or diarrhea with lack of strength or a feeling of being dizzy
  • No bowel movement in 3 days or when you feel uncomfortable
  • Signs of tumor lysis: Confusion or agitation, decreased urine, nausea/vomiting, diarrhea, muscle cramping, numbness and/or tingling, seizures.
  • Weight gain of 5 pounds in one week (fluid retention)
  • Swelling of your legs, ankles and/or feet
  • Pain that does not go away or is not relieved by prescribed medicine
  • Extreme weakness that interferes with normal activities
  • New rash and/or itching
  • Rash that is not relieved by prescribed medicines
  • If you think you may be pregnant

Reproduction Warnings

  • Pregnancy warning: This drug can have harmful effects on the unborn baby. Women of childbearing potential should use effective methods of birth control during your cancer treatment and for at least 30 days after treatment. Let your doctor know right away if you think you may be pregnant.
  • Breastfeeding warning: It is not known if this drug passes into breast milk. For this reason, women should not breastfeed during treatment because this drug could enter the breast milk and cause harm to a breastfeeding baby.
  • Fertility warning: In men, this drug may affect your ability to have children in the future. Talk with your doctor or nurse if you plan to have children. Ask for information on sperm banking.

Revised May 2019

This patient information was developed by Via Oncology, LLC © 2019. This information is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have.

CLIENT acknowledges that the Via Pathways and Via Portal are information management tools only, and that Via Oncology, LLC has not represented the Via Pathways or Via Portal as having the ability to diagnose disease, prescribe treatment, or perform any other tasks that constitute the practice of medicine. The clinical information contained in the Via Pathways and Via Portal are intended as a supplement to, and not a substitute for, the knowledge, expertise, skill, and judgment of physicians, pharmacists and other healthcare professionals involved with patient care at CLIENT facilities.