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What does it do?

Letrozole is used to treat breast cancer. Some breast cancers need the hormone oestrogen to grow. Letrozole reduces the amount of oestrogen in your body, which slows cancer growth.

Before you start

  • Tell your doctor if you have not gone through menopause, have liver problems, or if you have osteoporosis (weak bones).
  • Letrozole can weaken your bones. You may need tests to check for this before you start.

How should you take it?

Take letrozole regularly as directed with a glass of water.

What if you forget a dose?

If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Joint, muscle or bone aches and pains

Numb or tingling fingers

Hot flushing

Hair loss or thinning

Stomach upset

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.


This leaflet contains important, but not all, information about this medicine.

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. March 2023

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at Te Whatu Ora – Waitaha. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed