Abemaciclib is a type of targeted cancer drug. It is also known as Verzenios. It is a treatment for breast cancer that has:
- spread to another part of the body (advanced or metastatic breast cancer)
- spread to the area and structures surrounding the breast, such as nearby
lymph nodes, muscle and skin, but not to other parts of the body (locally advanced breast cancer)
You usually have this in combination with fulvestrant or an
Abemaciclib is only for a type of breast cancer that is hormone receptor positive (HR+) and
How abemaciclib works
Abemaciclib is a type of cancer growth blocker that targets the proteins cyclin dependant kinase 4 and 6 (CDK4 and CDK6) on breast cancer cells.
CDK 4 and CDK 6 are proteins that stimulate cancer cells to divide and grow.
Abemaciclib works by blocking these proteins. It aims to slow or stop the growth of the cancer.
How you take abemaciclib
You take abemaciclib as tablets. You take it with or without food and swallow the tablets whole with water.
Taking your tablets
You should take the right dose, not more or less.
Talk to your healthcare team before you stop taking a cancer drug, or if you miss a dose.
When you have abemaciclib
You take abemaciclib twice a day. Usually the morning and evening, about 12 hours apart. You take abemaciclib for as long as it’s working, and the side effects aren’t too bad.
You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.
Side effects can vary from person to person. They also depend on what other treatments you're having.
When to contact your team
Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:
you have severe side effects
your side effects aren’t getting any better
your side effects are getting worse
Early treatment can help manage side effects better.
Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.
We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.
Common side effects
These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:
Increased risk of infection
Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.
Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection.
Breathlessness and looking pale
You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.
Bruising, bleeding gums or nose bleeds
This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae).
Loss of appetite
You might lose your appetite for various reasons while having cancer treatment. Sickness, taste changes or tiredness can put you off food and drinks.
Taste changes may make you go off certain foods and drinks. You may also find that some foods taste different from usual or that you prefer to eat spicier foods. Your taste gradually returns to normal a few weeks after your treatment finishes.
This drug might make you feel dizzy. Don’t drive or operate machinery if you have this.
Feeling or being sick
Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.
It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.
Contact your advice line if you have diarrhoea, such as if you've had 4 or more loose watery poos (stools) in 24 hours. Or if you can't drink to replace the lost fluid. Or if it carries on for more than 3 days.
Your doctor may give you anti diarrhoea medicine to take home with you after treatment. Eat less fibre, avoid raw fruits, fruit juice, cereals and vegetables, and drink plenty to replace the fluid lost.
You could lose all your hair. This includes your eyelashes, eyebrows, underarms, legs and sometimes pubic hair. Your hair will usually grow back once treatment has finished but it is likely to be softer. It may grow back a different colour or be curlier than before.
Skin problems include a rash and itchy skin. Less commonly your skin might get dry. These skin conditions usually go back to normal when your treatment finishes. Your healthcare team can tell you what products you can use on your skin to help.
Tiredness and weakness
You might feel very tired and as though you lack energy.
Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.
High temperature (fever)
If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.
You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.
Occasional side effects
These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:
blood clots that can be life threatening; signs of pain, swelling and redness where the clot is. Feeling breathless can be a sign of a blood clot on the lung. Contact your advice line or doctor straight away if you have any of these symptoms
inflammation of the lungs that can be serious. Tell your doctor or nurse straight away if you have symptoms such as shortness of breath, cough and a high temperature
Coping with side effects
We have more information about side effects and tips on how to cope with them.
What else do I need to know?
Other medicines, foods and drinks
Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.
This drug contains lactose (milk sugar). If you have an intolerance to lactose, contact your doctor before taking this medicine.
Grapefruit and grapefruit juice
You should not eat grapefruit or drink grapefruit juice when you are taking this drug because it may increase the side effects.
Loss of fertility
It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
Contraception and pregnancy
It is unknown whether treatment may or may not harm a baby developing in the womb. It is important not to become pregnant while you are having treatment.
Women having abemaciclib should use 2 forms of contraception during treatment and for at least 21 days (3 weeks) after treatment finishes.
Talk to your healthcare team about contraception you can use during treatment.
It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment.
Treatment for other conditions
Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment. For example, if you need treatment for anything else, including teeth problems.
Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.
In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.
You can have:
- other vaccines, but they might not give you as much protection as usual
- the flu vaccine (as an injection)
- the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment
Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your
Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.
If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.
Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.
More information about this treatment
For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.
You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.
This page is due for review. We will update this as soon as possible.