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Overview: Zenbexus is used to treat multiple myeloma. Common side effects include infections, tiredness, muscle or joint pain, diarrhea, problems with muscle control, rash, sleep problems, constipation, and low blood cell levels. Call your health care provider right away if you have a fever, infection, or symptoms of a blood clot, such as chest pain, shortness of breath, confusion, or pain or swelling in your legs. Because Zenbexus can harm a fetus, it is only available through a special program, from certain pharmacies, and to certain people. Zenbexus is a capsule that is taken by mouth.

Uses

What is Zenbexus used for?

Zenbexus (iberdomide) is commonly used to treat certain people with multiple myeloma, which is a type of blood cancer.

Learn more about Zenbexus for Multiple Myeloma

Zenbexus may also be used for other conditions as determined by your health care provider.

How does Zenbexus work (mechanism of action)?

Zenbexus is a type of medicine known as a cereblon-modulating protein degrader. You may also hear it called a cereblon E3 ligase modulator (CELMoD). 

Cereblon is a protein in the body that identifies and tags certain other proteins for destruction. These proteins are needed for multiple myeloma cells to survive and grow. Zenbexus works with cereblon to tag these proteins in multiple myeloma cells, causing the cells to be destroyed. It also helps the body’s immune system release certain cells that help kill multiple myeloma cells. 

How is Zenbexus supplied (dosage forms)?

Brands and other names

  • Zenbexus

Dosage forms and strengths

  • 0.75 mg, 1 mg oral capsules

How should I store Zenbexus?

Zenbexus should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Keep Zenbexus in its original bottle, and make sure to close the cap tightly after each dose. The bottle has a drying agent (desiccant) to help keep the medicine dry. Only open the bottle and take out the capsule when you are ready to take your dose.

Side Effects

What are the most common side effects of Zenbexus?

The most common side effects of Zenbexus are listed below. Tell your health care provider if you have any of these side effects that bother you.

There may be other side effects of Zenbexus that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Zenbexus?

While less common, the most serious side effects of Zenbexus are described below, along with what to do if they happen.

Severe Allergic Reactions. Zenbexus may cause allergic reactions, which can be serious. Stop taking Zenbexus and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Blood Clots. Zenbexus may cause a blood clot in your arteries or veins and could cause a stroke, heart attack, or venous thromboembolism, including a blood clot in the lungs (pulmonary embolism) or deep vein thrombosis (DVT). You may be at higher risk for blood clots if you have had a clot in the past or if you have certain risk factors, such as high blood pressure, high cholesterol, or if you smoke. You may need to take other medicines to reduce the risk of blood clots while taking Zenbexus. Stop taking Zenbexus and get emergency help if you have any of the following signs of blood clots. 

  • Chest pain or pressure
  • Fast or abnormal heartbeat
  • Trouble breathing
  • Pain in your back, jaw, throat, or arm
  • Sweating, upset stomach, vomiting, or dizziness
  • Sudden weakness on one side of your body
  • Sudden and severe headache
  • Slurred speech or trouble understanding speech
  • Pain, swelling, or tenderness in your arm or leg
  • Vision loss
  • Bulging eyes 
  • Double vision

Low Neutrophil Levels (Neutropenia). Zenbexus may cause low levels of a type of white blood cell (called neutrophils), which is known as neutropenia. Neutrophils help prevent infection. Having a low level of neutrophils may increase your risk of infection. Keep all appointments for blood work. Tell your health care provider right away if you have any of the following symptoms of low neutrophil levels.

  • Fever, chills, or sweats
  • Tiredness
  • Sore throat, cough, or shortness of breath
  • Mouth or throat sores
  • Swollen lymph nodes

Infections. Zenbexus can increase your risk of infections, including serious or life-threatening infections. Call your health care provider right away if you have an infection or any of the following symptoms.

  • Burning or stinging when you pee 
  • Coughing, or coughing up blood
  • Fever, sweats, chills, or muscle aches
  • Shortness of breath
  • Diarrhea or stomach pain
  • Weight loss

Cancer. Zenbexus can cause a new cancer to develop or cause a previously treated cancer to come back. Tell your health care provider about any new symptoms that you may get.

Warnings & Precautions

Who should not use Zenbexus?

Allergies to Ingredients. People who are allergic to any of the following should not take Zenbexus.

  • Iberdomide
  • Zenbexus
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in Zenbexus.

Pregnancy. Do not take Zenbexus if you are pregnant. If you become pregnant, contact your health care provider right away. See the Pregnancy section for more details.

What should I know about Zenbexus before using it?

Do not take Zenbexus unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share Zenbexus with other people, even if they have the same condition as you. It may harm them.

Keep Zenbexus out of the reach of children.

Zenbexus is only available through a special program, from certain pharmacies, and to certain people. It is important that you keep all of your appointments, including labs or other testing, while taking Zenbexus. If you have any questions about this program, you can go to www.ZenbexusREMS.com or call 888-423-5436.

Do not open, chew, cut, or crush Zenbexus. Swallow the capsules whole with water. 

If the capsules break or you touch the contents of the capsule, wash the affected area right away with soap and water. Avoid causing dust while cleaning up the medicine.

Do not donate blood while you are taking Zenbexus and for 4 weeks after your last dose. 

Do not donate eggs or donate sperm while taking Zenbexus and for 4 weeks after your last dose. See the Pregnancy section for details. 

Zenbexus may make it hard for you to get pregnant or get your partner pregnant. If you have concerns, talk to your health care provider.

What should I tell my health care provider before using Zenbexus?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if Zenbexus is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have or have had any of the following.

Other Medicines and Supplements. Zenbexus may interact with other medicines and supplements. Before taking Zenbexus, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Zenbexus can harm a fetus. Because of this risk, Zenbexus is only available through a special program called the Zenbexus Risk Evaluation and Mitigation Strategy (REMS). If you can get pregnant, you will need to have 2 negative pregnancy tests at certain times before you can start taking Zenbexus. You will need to either completely abstain from sex or use two forms of effective birth control for at least 4 weeks before starting Zenbexus, during Zenbexus treatment, and for at least 4 weeks after your last dose. You will also need to have regular pregnancy tests while taking Zenbexus. Stop taking Zenbexus and tell your health care provider right away if you are pregnant, think you might be pregnant, miss your period or have any unusual menstrual bleeding, or plan to become pregnant. 

If you are able to get your partner pregnant, you will need to use effective birth control (condoms) while taking Zenbexus and for at least 4 weeks after your last dose. You will need to use condoms even if you have had a vasectomy. If you get your partner pregnant while taking Zenbexus, call your health care provider right away.

Breastfeeding. Do not breastfeed while you are taking Zenbexus. It is not known if Zenbexus passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

How can I get more information about Zenbexus?

For more information about Zenbexus, you can visit the drugmaker’s website at www.bms.com or www.zenbexus.com or call them at 855-673-4861.

Interactions

Does Zenbexus interact with foods or drinks?

Ask your health care provider if you should avoid eating grapefruit or drinking grapefruit juice while taking Zenbexus. The combination may increase blood levels of the medicine, possibly raising the risk of side effects. 

It is unknown if drinking alcohol will affect Zenbexus, but heavy drinking can slow your immune response and make it harder for your body to fight cancer. 

Does Zenbexus interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking Zenbexus.

  • Fluconazole (Diflucan), itraconazole (Sporanox, Tolsura), ketoconazole, posaconazole (Noxafil), or voriconazole (Vfend), which is a medicine used for fungal infections
  • Diltiazem (Cardizem CD and others) or verapamil (Verelan, Verelan PM), which is a medicine used for high blood pressure or other conditions
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis
  • which is a medicine to control seizures
  • Carbamazepine (Carbatrol, Tegretol, and others), which is a medicine commonly used to treat seizures or nerve pain
  • Erythromycin (Ery-Tab and others) or ciprofloxacin (Cipro), which is a medicine used for bacterial infections
  • Phenobarbital, phenytoin (Dilantin, Phenytek, and others), or primidone, which is a medicine that may be used to treat seizures
  • St. John’s wort, which is a supplement that may be used for depression

Many other medicines may alter the blood levels of Zenbexus. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with Zenbexus. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much Zenbexus?

If you or someone else has used too much Zenbexus, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Zenbexus?

If you miss a dose and it has been less than 12 hours since the missed dose, take it as soon as you remember. If it has been more than 12 hours since the missed dose, skip the missed dose and only take the next dose as regularly scheduled. Do not take double or extra doses.