Everolimus (Afinitor)

Everolimus (also known by its brand name Afinitor) is a targeted therapy and is one of a group of drugs called mTOR inhibitors.

mTOR is a protein which affects how cancer cells divide and grow. It also has a role in the development of hormone-therapy resistant breast cancer. This is breast cancer that comes back or progresses in someone who is taking hormone therapy.

Everolimus blocks mTOR which helps to stop or slow down the growth of the cancer.

When given with the aromatase inhibitor exemestane, it may delay the development of resistance to hormone therapy.  

How is it given?

Everolimus is given as a tablet once a day, with or without food alongside exemestane.

Who might be offered everolimus?

Everolimus may be offered to post-menopausal women with ER positive, HER2 negative locally advanced or secondary breast cancer whose cancer has progressed or recurred when taking the drugs letrozole, anastrozole or tamoxifen.

Research is continuing to look at the benefits of giving everolimus to other groups of women (for example, women with HER2 positive secondary breast cancer).

What are the side effects of everolimus?

Like any drug, everolimus can cause side effects. However, everyone reacts differently to drugs and some people experience more side effects than others.

Because it’s given with exemestane, you may also experience side effects from that drug as well.

If you experience any problems or side effects, regardless of whether they’re listed here, talk to your specialist team as soon as possible as they may be able to help you. If your side effects are severe, your specialist may recommend pausing the treatment (for a week or two) and/or reducing the dose.

Sore mouth

Before starting treatment, your specialist team may recommend you see a dentist to check the health of your mouth. Everolimus may cause your mouth or gums to be sore which can make eating and drinking difficult. This can happen very early on in your treatment. Your specialist team should suggest non-alcohol mouthwashes to help. Use a soft toothbrush after every meal and take regular sips of water to keep your mouth moist and stop you getting dehydrated. It can help to eat foods that don’t need much chewing and to avoid spicy foods or foods that are very hot or cold.

Fatigue (extreme tiredness)

You may experience tiredness that doesn’t go away with rest or sleep and this may affect you physically and emotionally. Find out more about fatigue.

Skin rash

This can be uncomfortable and itchy. Using moisturizer and sunscreen can help. Your specialist team can prescribe drugs if the rash is inflamed or itchy.


If you have diarrhoea, drugs can usually be prescribed to help.

Inflammation of the lungs (pneumonitis)

If you develop any shortness of breath, pain when breathing or a persistent, dry cough, contact your specialist team.

Raised blood glucose levels (hyperglycaemia)

You may be unaware of changes to your blood glucose levels, but you will have regular blood tests to check these while taking everolimus.

Bruising and bleeding

Platelets are a type of blood cell that helps the blood to clot. You may bruise more easily, have nosebleeds or your gums may bleed when you brush your teeth. Tell your specialist team if you notice any of these symptoms.

Risk of infection

When white blood cells fall below a certain level you can be more at risk of getting an infection, this is known as neutropenia. If you also have a high temperature (above 38°C), it’s known as febrile neutropenia.

If this happens, contact the hospital immediately. You’ll need to be treated with antibiotics.


Having too few red blood cells may mean you’re anaemic. Symptoms include feeling particularly tired, breathless or dizzy. Tell your specialist team if you notice any of these symptoms.

High cholesterol

You will have regular blood tests while taking everolimus to check your cholesterol levels.

Nausea and vomiting

You may feel sick at times during your treatment and may be sick (vomit). Anti-sickness tablets can be prescribed to help.

Kidney problems

Everolimus can affect how well your kidneys work. You’ll have regular blood tests while taking it to check how well they are working. 

If you have any concerns about taking everolimus, talk to your specialist or call us on 0808 800 600

Last reviewed: March 2015
Next planned review begins 2017

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