Anastrozole 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.

Anastrozole is used to treat breast cancer in postmenopausal women. It is often given to women whose cancer has progressed even after taking tamoxifen (Nolvadex, Soltamox).

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

Do not use anastrozole if you are pregnant. It could harm the unborn baby.

You may need to take a pregnancy test before using anastrozole, to make sure you are not pregnant.

You should not use this medication if you are allergic to anastrozole, if you are breast-feeding a baby, or if you have not yet completed menopause. Anastrozole is not for use in men or children.

Before using anastrozole, tell your doctor if you have heart disease, circulation problems, a history of stroke or blood clot, severe liver disease, high cholesterol, osteoporosis, or low bone mineral density.

Anastrozole may not work as well if you take it together with tamoxifen or an estrogen medication (such as hormone replacement therapy, estrogen creams, or birth control pills, injections, implants, skin patches, and vaginal rings). Before you start taking anastrozole, tell your doctor if you also take tamoxifen or estrogen.

You may need to keep taking anastrozole for up to 5 years. Follow your doctor's instructions.

You should not use this medication if you are allergic to anastrozole, if you are breast-feeding a baby, or if you have not yet completed menopause. Anastrozole is not for use in men or children.

To make sure you can safely take anastrozole, tell your doctor if you have any of these other conditions:

• heart disease;

• circulation problems;

• a history of stroke or blood clot;

• severe liver disease;

• high cholesterol; or

• osteoporosis or low bone mineral density.

Anastrozole can decrease bone mineral density, which may increase your risk of developing osteoporosis. Your bone mineral density may need to be tested before and during treatment with anastrozole.

FDA pregnancy category D. Do not use anastrozole if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment.

It is not known whether anastrozole passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using anastrozole.

You may need to take a pregnancy test before using anastrozole, to make sure you are not pregnant.