Sounds like 'let-ro-zole'

Easy-to-read medicine information about letrozole – what it is, how to take letrozole safely and possible side effects.

Type of medicine Also called
  • Belongs to a group of medicines known as aromatase inhibitors
  • Letara®
  • Letraccord®

What is letrozole?

  • Letrozole is used to treat some types of breast cancer in women who have had their menopause.
  • Some breast cancers need the female hormone, oestrogen, to grow. Letrozole works by blocking an enzyme aromatase and reduces the amount of oestrogen made by the body. In this way it slows or stops the growth of the cancer cells.
  • Letrozole belongs to a group of medicines known as aromatase inhibitors.
  • Read more about breast cancer.


  • The usual dose of letrozole is 1 tablet (2.5 mg) once a day.
  • Letrozole is a long-term treatment; you may have to take it for several years.

How to take letrozole?

  • Take letrozole at the same time each day.
  • You can take letrozole with or without food.
  • It is not harmful if you miss a dose of letrozole. If you forget to take your tablet, take it as soon as you remember that day.
  • But, if it is nearly time for your next tablet, just take the next tablet at the right time. Do not take double the amount of tablets.
  • Do not stop taking letrazole suddenly; speak to your doctor before stopping.

Possible side effects

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

Side effects What should I do?
  • Nausea, feeling sick or vomiting
  • Try taking letrozole with food or just before bed
  • Hot flushes
  • Sweating
  • Joint pain, stiffness 
  • Feeling tired, lack of energy 
  • Vaginal dryness
  • Tell your doctor or pharmacist if troublesome
  • Vaginal bleeding 
  • Swollen legs or feet
  • Tell your doctor.


  • Letrozole may interact with a number of medications and herbal supplements so check with your doctor or pharmacist.

Learn more

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr Janine Bycroft, GP July 2014