Exemestane for breast cancer (Aromasin)

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Take one 25 mg exemestane tablet a day, with food.

The most common side-effects are hot flushes, feeling sick, joint pain, and feeling tired. These occur in up to 1 in 4 women when first taking exemestane. The side-effects will settle as your body adjusts to the medicine.

Type of medicineAn aromatase inhibitor hormone antagonist
Used forBreast cancer
Also calledAromasin®
Available asTablets

Exemestane is known as a hormonal breast cancer treatment.

Some breast cancers need the hormone oestrogen to grow. In women who have been through the menopause, the main source of oestrogen is through the change of sex hormones called androgens into oestrogen. An enzyme called 'aromatase' is needed for this change to occur. Exemestane works by inhibiting (or blocking) this enzyme. This reduces the amount of oestrogen in your body, which slows the growth of the cancer cells.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking exemestane it is important that your doctor knows:

  • If you have not yet gone through the menopause, or if there is a possibility you might be pregnant.
  • If you have problems with the way your liver works, or the way your kidneys work.
  • If you have osteoporosis (a loss of bone density, or 'brittle bones').
  • If you have ever had an allergic reaction to a medicine.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The manufacturer's leaflet will give you more information about exemestane and a full list of the side-effects which you may experience from taking it.
  • Take one 25 mg tablet of exemestane each day, exactly as your doctor tells you to. Your dose will be printed on the label of the tablet pack to remind you.
  • Swallow the tablet with a drink of water, straight after a meal.
  • You may take exemestane with whichever meal of the day you find easiest to remember, but try to take your doses with the same meal each day. This will help you to avoid missing any doses.
  • If you forget to take a dose at your usual time, take it as soon as you remember. If you do not remember until the following day, skip the missed dose. Do not take two doses together to make up for a forgotten dose.
  • Continue to take the tablets regularly each day until your doctor tells you otherwise. You may need to take exemestane for a number of years.
  • Try to keep your regular appointments with your doctor or clinic. This is so your doctor can check on your progress. Exemestane lowers the levels of female hormones in your body, which can reduce the strength of your bones. You may need to have bone density tests before and during your treatment to check for this.
  • If you are due to have an operation or dental treatment, tell the person carrying out the treatment that you are taking exemestane.
  • If you buy any medicines, check with a pharmacist that they are safe to take with your other medicines.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with exemestane. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common exemestane side-effects
What can I do if I experience this?
Hot flushes, sweatingTry to keep cool by wearing light, airy clothes
Feeling tired, weak or dizzyDo not drive or use tools or machines until you feel better
Feeling or being sick, indigestion, abdominal painStick to simple meals - avoid rich or spicy foods
Headache, joint and muscle painAsk your doctor or pharmacist to recommend a suitable painkiller
ConstipationTry to eat a well-balanced diet and drink several glasses of water each day
DiarrhoeaDrink plenty of water to replace lost fluids
Loss of appetite, difficulty sleeping, feeling depressed, hair thinning, skin rash, swollen hands or feet, carpal tunnel problems (causing hand pain or tingling)Speak with your doctor if any of these become troublesome

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • Manufacturer's PIL, Aromasin® Tablets; Pfizer Limited, The electronic Medicines Compendium. Dated October 2012.
  • British National Formulary; 66th Edition (September 2013) British Medical Association and Royal Pharmaceutical Society of Great Britain, London

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
3786 (v24)
Last Checked:
Next Review:
The Information Standard - certified member

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