Letrozole lowers estrogen levels in postmenopausal women, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.

Letrozole is used to treat breast cancer in postmenopausal women. It is often given to women who have been taking tamoxifen (Nolvadex, Soltamox) for 5 years.

Letrozole may also be used for purposes not listed in this medication guide.

You should not use letrozole if you are pregnant.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

You may take letrozole with or without food.

You will need frequent medical tests, and your bone mineral density may also need to be checked.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Breast Cancer:

2.5 mg orally once a day

Duration of therapy:
-Adjuvant and extended adjuvant settings: Optimal duration is unknown; discontinue therapy at relapse.
-Advanced disease: Until tumor progression is evident.

Uses:
-Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
-Extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy
-First-line treatment of advanced breast cancer in postmenopausal women with hormone receptor positive or unknown locally advanced or metastatic breast cancer; second-line treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy

Usual Adult Dose for Breast Cancer -- Adjuvant:

2.5 mg orally once a day

Duration of therapy:
-Adjuvant and extended adjuvant settings: Optimal duration is unknown; discontinue therapy at relapse.
-Advanced disease: Until tumor progression is evident.

Uses:
-Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
-Extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy
-First-line treatment of advanced breast cancer in postmenopausal women with hormone receptor positive or unknown locally advanced or metastatic breast cancer; second-line treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy

You should not use letrozole if you are allergic to it.

letrozole is for use only in women who can no longer get pregnant. Letrozole can harm an unborn baby. Do not use if you are pregnant. Use effective birth control if you are not past menopause. Keep using birth control for at least 3 weeks after your last dose of letrozole. Tell your doctor if you think you may be pregnant.

Tell your doctor if you have ever had:

• liver disease (especially cirrhosis);

• osteoporosis, osteopenia (low bone mineral density);

• high cholesterol; or

• if you also take tamoxifen.

You should not breastfeed while you are using letrozole and for at least 3 weeks after your last dose.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Avoid driving or hazardous activity until you know how letrozole will affect you. Your reactions could be impaired.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Common side effects of letrozole may include:

• hot flashes, warmth or redness in your face or chest;

• headache, dizziness, weakness;

• bone pain, muscle or joint pain;

• swelling, weight gain;

• increased sweating; or

• increased cholesterol in your blood.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may affect letrozole, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to letrozole.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.