Letrozole is a medicine used to treat breast cancer and help to prevent breast cancer coming back.
It's mainly prescribed for women who have been through the menopause and have a type of cancer called hormone-dependent breast cancer.
Most people who take letrozole will have had primary treatment such as surgery, radiotherapy or sometimes chemotherapy to treat their breast cancer first. Letrozole is an additional (adjuvant) treatment which helps stop the cancer coming back.
Letrozole is sometimes given alongside another breast cancer medicine, called tamoxifen.
Letrozole is available on prescription only and comes as tablets.
It can also be used:
- to prevent breast cancer if you're high risk and have been through the menopause
- to treat cancer if you cannot have surgery, or to shrink the cancer before surgery if you cannot have chemotherapy
It can sometimes be used to treat breast cancer in men, or in women who have not reached the menopause.
Letrozole can occasionally be used as a fertility treatment if you have polycystic ovary syndrome (PCOS). If you're taking it as a fertility treatment and you need more information, speak to your specialist.
Find out more about medicines used as fertility treatments.
Find out more about polycystic ovary syndrome (PCOS).
Key facts
- You'll usually take letrozole once a day. Try to take it at the same time each day.
- Most people take letrozole for 5 years, but some will take it for up to 10 years.
- Common side effects include symptoms similar to the menopause such as hot flushes, tiredness and low mood. Side effects usually improve after a few months.
- Your doctor will monitor your blood pressure, cholesterol levels and bone density during your treatment.
- If letrozole makes you feel tired or dizzy, or if you get blurred vision, do not drive a car, ride a bike, or use tools or machinery until you feel better.