Sounds like 'ex-eh-mes-tane'

Key points about exemestane

  • Exemestane is used to treat some types of breast cancer for women who have gone through menopause.
  • Exemestane is a long-term treatment so you may have to take it for several years.
  • Find out how to take it safely and possible side effects.
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Exemestane is used to treat some types of breast cancer for women who have gone through menopause. The type of breast cancer exemestane is used for is called oestrogen receptor-positive (ER-positive) breast cancer. Exemestane belongs to a group of medicines called aromatase inhibitors.

After menopause, the ovaries no longer produce oestrogen but it continues to be made at low levels in fat and other tissues. This happens when an enzyme called aromatase changes other hormones into oestrogen through a complex process. Aromatase inhibitors are a type of medicine that block this process and reduce the amount of oestrogen in the body. In this way exemestane slows or stops the growth of the cancer cells. Read more about aromatase inhibitors.(external link) 

In Aotearoa New Zealand exemestane is available as tablets (25 mg).

  • The usual dose of exemestane is 1 tablet once a day.
  • Exemestane is a long-term treatment so you may have to take it for several years.
  • Always take exemestane exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions.

  • Take exemestane at the same time each day, either in the morning or the evening.
  • It's best to take exemestane after a meal. 
  • If you forget to take your dose, take it as soon as you remember. But if it is nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.
  • Don't stop taking exemestane suddenly, talk to your doctor before stopping.

Here are some things to know when you're taking exemestane. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Exemestane can make you drowsy, especially when you first start taking it. Avoid driving and doing other tasks where you need to be alert until you know how this medicine affects you. It's best to take it at bedtime.
  • Exemestane can interact with some other medicines and herbal supplements, so check with your doctor or pharmacist before starting exemestane and before starting any new products.
  • Aromatase inhibitors, such as exemestane, may decrease bone mineral density (BMD) if you have been through menopause. This means you have a possible increased risk of fractures. You can help to keep your bones strong by regular weight-bearing exercise, eating a healthy diet rich in calcium and vitamin D and not smoking. If you are concerned, talk to your doctor about your risk. 

Like all medicines, exemestane can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Hot flushes and sweats

These are common and are often mild, but this can vary. Hot flushes and sweats may improve after the first few months. You can try to reduce hot flushes and sweats by not smoking, reducing alcohol and avoiding hot drinks containing caffeine, such as tea and coffee. Try to dress in layers, so you can remove clothes as needed, and wear clothes made from natural fabrics, such as cotton. If hot flushes are troubling you, tell your doctor or nurse. There are some medicines that can help to reduce flushes.


Other side effects

Side effects What should I do?
  • Stomach pain or upset
  • Nausea (feeling sick), or vomiting
  • Diarrhoea (runny poo)
  • Constipation
  • These are quite common when you start exemestane.
  • Try taking exemestane with food or just before bed
  • Tell your doctor if hey bother you..
  • Feeling tired, lack of energy
  • Sleep problems
  • Pain in the joints or muscles
  • Headache
  • These may improve with time.
  • Tell your doctor if troublesome.
  • Do not drive if drowsy.
  • Skin rashes, itching, swelling of the face, lips or mouth.
  • Vaginal bleeding
  • Tell your doctor immediately or ring Healthline 0800 611 116.
Did you know that you can report a medicine side effect to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.(external link)

Exemestane(external link) NZ Formulary, NZ
Exemestane Pfizer(external link) Medsafe Consumer Information


  1. Exemestane(external link) NZ Formulary
  2. Breast cancer(external link) NFormulary



Aromatase inhibitors
Breast Cancer Foundation, NZ

5 questions to ask about your medications


5 questions to ask about your medications
Health Quality and Safety Commission, NZ, 2019

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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