What is abemaciclib (Verzenios®)?

Abemaciclib (Verzenios®) is used to treat locally advanced or advanced (metastatic) breast cancer. It is only used if tests show that the cancer cells:

  • have hormone receptors (this is called hormone receptor-positive breast cancer)
  • do not have HER receptors (this is called HER2 receptor-negative breast cancer).

It is best to read this information with our general information about the type of cancer you have. 

Abemaciclib is a type of targeted therapy drug called a cancer growth inhibitor.

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment. 

How abemaciclib is given

Abemaciclib comes in tablets that you take twice a day, every day, without a break. You have this treatment in combination with a daily hormone therapy tablet or a monthly hormone therapy injection.

During treatment you will have regular blood tests and appointments with a cancer doctor, a chemotherapy nurse or a specialist nurse, or a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.

At your appointments, they will talk to you about your blood test results and ask how you feel on the treatment. If you have side effects, they can give you advice about managing these. Sometimes they may need to change the dose of abemaciclib. If you have many side effects they may delay your treatment for a time to let your body recover.

Taking abemaciclib tablets

Abemaciclib comes as tablets you can take at home. Your nurse or doctor will talk to you about your treatment plan. Always take the tablets exactly as explained. This is important to make sure they work as well as possible for you.

Your nurse or pharmacist may give you anti-diarrhoea drugs and other medicines to take home if needed. Take all your capsules or tablets exactly as they have been explained to you.

You can take abemaciclib with or without food. Take it at the same times every day. Swallow the tablets whole and do not chew, break or crush them.

You should avoid eating grapefruit or drinking grapefruit juice while you are taking abemaciclib. Grapefruit may affect how abemaciclib works.

If you forget to take the tablets, take the next dose at the usual time. Do not take a double dose.

Other things to remember about your tablets:

  • Keep them in the original package.
  • Keep them safe and out of sight and reach of children.
  • If you are sick after taking the tablets, contact the hospital. Take the next dose at the usual time. Do not take a double dose. 
  • If your treatment is stopped return any unused tablets to the pharmacist.

About side effects

We explain the most common side effects of this treatment here. We also include some less common side effects.

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Common side effects

Diarrhoea

This treatment often causes diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.

For many people diarrhoea starts in the first weeks of starting abemaciclib. You may have tummy cramps and need to find a toilet urgently. 

Sometimes diarrhoea can be severe. If you have diarrhoea:

  • always contact your doctor or nurse and ask for advice
  • start taking anti-diarrhoea drugs if your doctor, nurse or pharmacist gave you a supply
  • drink at least 2 litres (3½ pints) of fluids each day
  • avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods.

Contact the hospital straight away if:

  • you have diarrhoea at night
  • you have diarrhoea more than 4 times in a day
  • you have a moderate or severe increase in stoma activity
  • the anti-diarrhoea drugs do not improve the diarrhoea within 24 hours.

If you think that some foods are making your diarrhoea worse, tell your doctor or nurse. They can give you advice and may arrange for you to talk to a dietician.

Risk of infection

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is sometimes called neutropenia.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. Contact the hospital straight away on the 24-hour contact number you have been given if:

  • your temperature goes over 37.5°C (99.5°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection
  • your temperature goes below 36°C (96.8°F).

Symptoms of an infection include:

  • feeling shivery and shaking
  • a sore throat
  • a cough
  • breathlessness
  • diarrhoea
  • needing to pass urine (pee) a lot, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

You will have regular blood tests during treatment. If needed, your doctor may reduce or delay your treatment for a short time, until your cell count increases.

Bruising and bleeding

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

  • nosebleeds
  • bleeding gums
  • heavy periods
  • blood in your urine (pee) or stools (poo)
  • tiny red or purple spots on the skin that may look like a rash.

Tell your doctor if you have any unexplained bruising or bleeding. You may need a drip to give you extra platelets. This is called a platelet transfusion.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:

  • pale skin
  • lack of energy
  • feeling breathless
  • feeling dizzy and light-headed.

Tell your doctor or nurse if you have these symptoms.

If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Tiredness

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have enough time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Feeling sick

You may feel sick during treatment. Your doctor will give you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist tells you. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluids and eat small amounts often. If you continue to feel sick, or if you vomit more than once in 24 hours, contact the hospital as soon as possible. They will give you advice and may change the anti-sickness drug to one that works better for you.

Loss of appetite

This treatment can affect your appetite. Do not worry if you do not eat much for a day or two. But if your appetite does not come back after a few days, tell your nurse or dietitian. They will give you advice. They may give you food or drink supplements.

Changes to your taste

You may get a bitter or metal taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. Taste changes usually get better after treatment finishes. Your nurse can give you more advice.

Hair loss

Your hair may get thinner but you are unlikely to lose all the hair from your head. Your nurse can talk to you about ways to cope with any hair loss.

Skin changes

This treatment may cause a rash or itchy skin. Always tell your doctor or nurse about any skin changes. They can give you advice and may give you creams or medicines to help. If your skin feels dry, try using an unperfumed moisturising cream every day. Any changes to your skin are usually temporary and improve when treatment finishes.

Effects on the liver

This treatment can affect how your liver works. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your liver is working. Sometimes your doctor will stop abemaciclib for a time until this side effect improves.

Dizzinesss

This treatment can make you feel dizzy. This is usually mild. Tell your doctor or nurse if you feel dizzy or faint. If you feel dizzy or faint, do not drive or operate machinery.

Less common side effects

Effects on the lungs

This treatment can cause changes to the lungs. Rarely these can be serious. Tell your doctor if you develop:

  • a cough
  • wheezing
  • a fever (high temperature)
  • breathlessness.

You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs.

Effects on the eyes

This treatment can make your eyes water more than usual. This is usually mild.

Other information

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

  • throbbing pain, redness or swelling in a leg or arm
  • suddenly feeling breathless or coughing
  • sharp chest pain, which may be worse when you cough or take a deep breath.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

A blood clot is serious, but it can be treated with drugs that thin the blood (anticoagulants). Your doctor or nurse can give you more information.

You can help reduce the risk of developing a blood clot by:
  • staying active during treatment
  • drinking plenty of fluids, especially water.

You may be given anticoagulants to help prevent a clot.

Other medicines

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.

Lactose

This treatment contains a sugar called lactose. If you have a lactose intolerance, talk to you doctor before you start taking this.

Vaccinations

Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.

Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations.

If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines, such as shingles, contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.

Contraception

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

Breastfeeding

You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.

Your doctor or nurse can give you more information.

Fertility

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.

About our information


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.