If you have a certain type of advanced breast cancer, your doctor might suggest Verzenio (abemaciclib) as a treatment option for you.

Verzenio is a prescription medication used in adults to treat breast cancer that’s:

It’s used to treat this type of breast cancer in certain situations. For more information about Verzenio, including details about its uses, see this in-depth article on the drug.

Verzenio is a targeted therapy for breast cancer. Targeted therapies are drugs that attack cancer cells without harming healthy cells.

This drug comes as a tablet that you take by mouth. You’ll usually take it twice a day. If Verzenio works well for you without causing troublesome side effects, you’ll typically take it as a long-term treatment.

Like other drugs, Verzenio can cause mild or serious side effects. Keep reading to learn more.

Some people may experience mild or serious side effects during their Verzenio treatment. Some of these side effects are more common than others. Examples of side effects that were reported more commonly in studies of people who took Verzenio include:

* To learn more about this side effect, see “Side effects explained” below.

Some people who take Verzenio may have mild side effects. Examples of mild side effects that have been reported with Verzenio include:

* To learn more about this side effect, see “Side effects explained” below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Verzenio unless your doctor recommends it.

Verzenio may cause mild side effects other than the ones listed above. See the Verzenio patient information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Verzenio, visit MedWatch.

Some people who take Verzenio may have serious side effects. Examples of serious side effects that have been reported with Verzenio include:

* To learn more about this side effect, see “Side effects explained” below.
† An allergic reaction is possible after using Verzenio. But this side effect wasn’t reported in studies.

If you develop serious side effects while taking Verzenio, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Below you’ll find more detail about some of the side effects Verzenio may cause.

Hair loss

Some people who take Verzenio may experience hair loss or hair thinning.

Hair loss is also possible with other drugs that are sometimes used with Verzenio. These include Faslodex (fulvestrant), Femara (letrozole), and Arimidex (anastrazole). You may be more likely to have hair loss or thinning if you take Verzenio with one of these drugs.

What might help

You can help minimize hair loss by being gentle when washing, brushing, and styling your hair. You may want to avoid braiding, blow-drying, curling, or straightening your hair.

If you have troublesome hair loss or thinning while taking Verzenio, talk with your doctor or a healthcare professional. They can suggest ways to help you manage this side effect. For example, they may be able to give advice about wigs or other scalp coverings, such as scarves.

If your hair gets very thin or you lose it completely, it’s important to protect your scalp from sunlight and cold. You can do this by wearing a hat or headscarf.

Diarrhea

You may have diarrhea while taking Verzenio. It’s one of the drug’s most common side effects.

Diarrhea is usually mild and typically goes away in a few days or weeks. However, diarrhea can sometimes become more severe, possibly leading to dehydration. With dehydration, your body loses too much fluid.

Diarrhea is most likely to occur in the first month after you start taking Verzenio.

What might help

Your doctor will monitor you closely for this side effect while you take Verzenio. It’s important that this side effect is managed early to keep it from becoming severe. So if you start having loose stools, you should:

  • tell your doctor right away
  • start taking medication to treat diarrhea, such as Imodium (loperamide), as directed by your doctor
  • drink plenty of fluids

If the diarrhea doesn’t ease within 24 hours of taking antidiarrheal medication, tell your doctor. They may ask you to stop taking Verzenio temporarily until the condition gets better. Your doctor will monitor you to make sure the diarrhea doesn’t get worse.

When your doctor decides you can start taking Verzenio again, they may prescribe a lower dose.

If you have particularly troublesome diarrhea with Verzenio, your doctor may recommend switching to a different medication for your breast cancer.

Nausea

Nausea is another common side effect of Verzenio. Some people also have vomiting while taking this medication.

Nausea is usually mild and goes away in a few days or weeks. But some people have nausea that lasts longer than this or leads to vomiting.

If you have vomiting, this can be more serious because it could lead to dehydration. With dehydration, your body loses too much fluid.

What might help

If you have nausea or vomiting with Verzenio, talk with your doctor about ways to manage these side effects. They may recommend taking anti-nausea medication.

Other things you can try to reduce nausea include:

  • sipping fluids regularly over the day
  • eating little and often, rather than having three main meals
  • avoiding greasy, spicy, or very sweet foods
  • trying complementary remedies, such as acupuncture or breathing techniques

If you have nausea after taking Verzenio without food, you could also try taking it with food. Likewise, if you have nausea after taking the drug with food, try taking it without food.

If you vomit after taking a dose of Verzenio, don’t take another dose. Just continue with your usual dosing schedule. But if this happens often, be sure to tell your doctor. They may prescribe anti-nausea medication. Or they may recommend switching to a different medication for your breast cancer.

Blood clots

Blood clots are a rare side effect of Verzenio.

The blood clots that have been reported include:

Symptoms of blood clots may include:

What might help

Talk with your doctor about your risk for blood clots while taking Verzenio.

If you have symptoms of a blood clot while taking Verzenio, see your doctor right away. But if your symptoms feel life threatening, call 911 or your local emergency number.

If you’re diagnosed with a blood clot, your doctor will prescribe medication to treat this. It’s possible you might need to stop taking Verzenio. Your doctor may recommend switching to a different medication for your breast cancer.

Allergic reaction

Like most drugs, Verzenio can cause an allergic reaction in some people. But this side effect wasn’t reported in studies.

Symptoms can be mild or serious and may include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine), or a product you apply to your skin, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms you had a mild allergic reaction to Verzenio, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Verzenio, they may have you switch to a different treatment.

Keeping track of side effects

During your Verzenio treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how the drug affects you. And your doctor can use this information to adjust your treatment plan if needed.

Here are the answers to some frequently asked questions about Verzenio’s side effects.

Can taking Verzenio lead to eye-related side effects?

Verzenio isn’t known to cause any eye-related side effects. There weren’t any vision or eye-related side effects reported in studies of the drug.

Verzenio is sometimes used with other medications to treat breast cancer. These include Femara (letrozole) and Arimidex (anastrazole). Eye-related side effects, such as cataracts, have been reported with these medications.

Talk with your doctor if you notice any changes in your vision while taking Verzenio, either on its own or with other medications.

Will I need any lab tests while taking Verzenio?

Yes, you will. Verzenio can sometimes cause problems with your liver or blood cells. So you’ll have frequent blood tests to check for these side effects. Tests your doctor will order include the following.

Complete blood counts. These measure the levels of different blood cells in your body. They can show if you have:

Your blood cells have functions that depend on their type: White blood cells help your body fight infections. Red blood cells carry oxygen to different parts of your body. And platelets help your blood to clot if you have an injury.

Liver function tests. These measure the levels of liver enzymes in your blood. Liver enzymes are proteins that help your liver carry out its usual functions. If you have increased levels of liver enzymes in your blood, this can show a problem with your liver.

The following chart lists the symptoms you might have for low blood cell levels and for liver problems.

ConditionSymptoms
neutropenia• fever
• other signs of infection
anemiashortness of breath
• feeling tired
thrombocytopenia• bruising easily
• taking longer than usual to stop bleeding
liver problemsjaundice (yellowing of your skin or the whites of your eyes)
• pain in your upper right belly
loss of appetite
• bruising easily

If you have any of the above symptoms while taking Verzenio, see your doctor. You may need a blood test to check your blood cells or liver function.

If tests show a problem with your blood cells or liver, your doctor may ask you to stop taking Verzenio until the condition improves. When your doctor decides you can start taking Verzenio again, they may prescribe a lower dose. But if your blood cells or liver function don’t improve, your doctor may recommend switching to a different medication for your breast cancer.

Can Verzenio give you a cough?

Yes, Verzenio can sometimes cause a cough. In studies, a cough was commonly reported by people taking Verzenio. Coughs are usually mild and typically get better in a few days or weeks.

In rare cases, a cough may be a symptom of a lung problem, which can be a serious side effect of Verzenio.

Serious lung problems reported with Verzenio include pneumonitis (lung inflammation) and interstitial lung disease (inflammation, scarring, and stiffening of the lungs). Other symptoms of these lung problems can include shortness of breath, trouble breathing, chest pain, fast heartbeat, and confusion.

If you have a cough or any other symptoms of lung problems while taking Verzenio, see your doctor. If you have a serious lung problem, your doctor may reduce your dose of Verzenio. Or they may ask you to stop treatment temporarily. If the problem doesn’t improve, your doctor may recommend switching to a different medication for your breast cancer.

Verzenio may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Verzenio. The list below includes factors to consider.

Liver or kidney problems. If you already have a problem with how well your liver or kidneys work, taking Verzenio could make it worse. Your doctor may prescribe a dosage of Verzenio that’s lower than usual. And they’ll frequently monitor your liver and kidney function. But in some cases, you may not be able to take Verzenio.

Allergic reaction. If you’ve had an allergic reaction to Verzenio or any of its ingredients, you should not take Verzenio. Ask your doctor what other medications are better options for you.

Low white blood cell count. If you already have a low white blood cell count, taking Verzenio could make it worse. This could raise your risk for serious infections. If you have a low white blood cell count, you may not be able to start taking Verzenio until this improves.

Infections. Verzenio can lower your white blood cell count. White blood cells help your body fight infections. So Verzenio could make it harder for your body to fight any infections you already have. If you have an active infection, you may not be able to start Verzenio until it has cleared. Your doctor may prescribe medication to treat the infection.

Alcohol use and Verzenio

Alcohol isn’t known to interact with Verzenio. However, drinking alcohol could worsen certain side effects of Verzenio. These include fatigue, nausea, diarrhea, and headache.

Both alcohol and Verzenio can also cause liver problems. So if you drink alcohol while taking Verzenio, this might raise your risk for liver problems.

If you drink alcohol, talk with your doctor about how much is safe to drink while you’re taking Verzenio.

Pregnancy and breastfeeding while taking Verzenio

Verzenio is not safe to take during pregnancy. If you can become pregnant, you’ll need to have a pregnancy test before you start Verzenio. This is so your doctor can be sure you’re not pregnant.

It’s not known if Verzenio gets into breast milk. You should not breastfeed while you’re taking Verzenio, because of the chance it could harm a breastfed child.

If you’re pregnant or breastfeeding, talk with your doctor about suitable treatment options for your breast cancer.

Most common side effects of Verzenio are mild and go away on their own in a few days or weeks. But some serious side effects are also possible.

Before deciding if Verzenio is a good option for you, you should talk with your doctor about its possible risks and benefits. Examples of some questions you might want to ask include:

  • Do my past breast cancer treatments put me at a higher risk for side effects with Verzenio?
  • How do Verzenio’s side effects compare with those from other treatment options?
  • Do I need to take measures to prevent infections while taking Verzenio?
  • Will taking Verzenio raise my risk for COVID-19?

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.