Drugs A - Z

Letrozole Oral tablet

Certain types of breast cancer grow under the influence of estrogen

Generic Name: letrozole  |  Brand Name: Femara

Brand Names: Femara

What is this medicine?

LETROZOLE (LET roe zole) blocks the production of estrogen. Certain types of breast cancer grow under the influence of estrogen. Letrozole helps block tumor growth. This medicine is used to treat advanced breast cancer in postmenopausal women.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • liver disease
  • osteoporosis (weak bones)
  • an unusual or allergic reaction to letrozole, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. You may take it with or without food. Follow the directions on the prescription label. Take your medicine at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following medications:
  • estrogens, like hormone replacement therapy or birth control pills

This medicine may also interact with the following medications:

  • dietary supplements such as androstenedione or DHEA
  • prasterone
  • tamoxifen

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular check-ups to monitor your condition.

Do not use this drug if you are pregnant. Serious side effects to an unborn child are possible. Talk to your doctor or pharmacist for more information.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • allergic reactions like skin rash, itching, or hives
  • bone fracture
  • chest pain
  • difficulty breathing or shortness of breath
  • severe pain, swelling, warmth in the leg
  • unusually weak or tired
  • vaginal bleeding

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • bone, back, joint, or muscle pain
  • dizziness
  • fatigue
  • fluid retention
  • headache
  • hot flashes, night sweats
  • nausea
  • weight gain

Where should I keep my medicine?

Keep out of the reach of children.

Store between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.


Last Updated: February 27, 2009
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