Arimidex 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. Arimidex is used to treat breast cancer in postmenopausal women. 1.3 Second-Line Treatment ARIMIDEX is indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy. Patients with ER-negative. Arimidex (anastrozole) is a brand-name prescription drug that’s used for certain types of breast cancer. Learn about side effects, warnings, dosage, and more. Arimidex (Anastrozole) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. Anastrozole (Arimidex) is prescription oral medication used to treat certain types of breast cancer, including both early and advanced or metastatic stages. It's FDA approved only for postmenopausal women, or those who have already gone through menopause. Learn about side effects and more for Arimidex (anastrozole), a prescription tablet that treats certain kinds of breast cancer in females who have gone through menopause. Find patient medical information for Anastrozole (Arimidex) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings 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. It is also used for first-line treatment of hormone receptor-positive or hormone receptor-unknown advanced or metastatic (cancer that has spread) breast cancer. Anastrozole is also used to treat advanced breast cancer that has grown or spread after tamoxifen treatment. Arimidex is an aromatase inhibitor used to treat all stages of hormone receptor-positive breast cancer in postmenopausal women.