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Exemestane (Aromasin)

Find out what exemestane is, how you have it and other important information about taking exemestane. 

Exemestane is a type of hormone therapy drug and is also known by its brand name, Aromasin.

It is a treatment for women with breast cancer who have had their menopause.

How it works

Many breast cancers are stimulated to grow by the female sex hormones oestrogen and progesterone. These breast cancers are called hormone sensitive or hormone receptor positive. Blocking the effects of these hormones can treat breast cancer.

In women who have had their menopause, oestrogen is mainly produced by changing androgens (sex hormones produced by the adrenal glands) into oestrogens. This process is called aromatisation and happens mainly in the fatty tissues, muscle and the skin. It needs a particular enzyme called aromatase.

Exemestane blocks the process of aromatisation. So it lowers the amount of oestrogen in the body. In early breast cancer, taking exemestane can help to stop breast cancer coming back. In advanced breast cancer, the cancer cells may grow more slowly or stop growing completely.

How you have it

You have exemestane as tablets. Try to take it at the same time each day. Swallow the tablet whole with a drink of water. You should take it after food.

Taking your tablets

You must take tablets according to the instructions your doctor or pharmacist gives you.

You should take the right dose, not more or less.

Talk to your specialist or advice line before you stop taking a cancer drug.

If you accidentally take more exemestane than you should, let your doctor know straight away.

If you forget to take a tablet, take it as soon as you remember. If it is nearly time for the next dose, take that tablet at the usual time. Don't take a double dose to make up for the missed one.

When you have exemestane

You take exemestane once a day, usually for a few years.


You might have blood tests before starting treatment and during your treatment. They check your general health and might check your levels of blood cells and other substances in the blood.

Side effects

Important information

Other medicines, food and drink

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.

Do not take hormone replacement therapy while you are having exemestane treatment.

Treatment for other conditions

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.

Sugar intolerance

Exemestane contains a small amount of sucrose (a type of sugar). Tell your doctor if you have an intolerance to any type of sugar.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Information and help

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About Cancer generously supported by Dangoor Education since 2010.