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What does it do?

Letrozole is used to treat and prevent breast cancer.

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 (e.g. black cohosh) or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Symptoms of a blood clot including: sudden shortness of breath, swelling or pain in one leg

Tell your doctor immediately

Joint, muscle or bone aches and pains

Sore breasts

Chest pain, ankle or feet swelling, cough

Numbness or tingling of the fingers or toes

Tell your doctor

Trouble sleeping, changes in vision

Hair loss or thinning

Headache, dizziness, low mood, nervousness

Hot flushing, sweating, fever

Stomach pain, change of appetite, diarrhoea

Muscle weakness, tiredness

Nasal stuffiness

Vaginal dryness

Tell your doctor if troublesome

Stomach upset

Take with food

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

Other information:

  • Tell your doctor if you have liver problems, high blood pressure, high cholesterol, osteoporosis (weak bones), or if you have had a stroke, ‘mini-stroke’, or blood clot.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Hormone replacement therapy and oral contraceptives should not be taken with letrozole. A barrier form of contraception (condoms) should be used.
  • Tell your doctor if you still have periods while taking letrozole.
  • Letrozole may make you dizzy or sleepy and make it dangerous to drive, operate machinery or do other activities that require you to be alert. Limit alcohol intake because it can increase these effects.

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

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. February 2018

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 the Canterbury District Health Board. 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