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 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. Arimidex is an aromatase inhibitor used to treat all stages of hormone receptor-positive breast cancer in postmenopausal women. 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, sold under the brand name Arimidex among others, is an antiestrogenic medication used in addition to other treatments for breast cancer. [7][8] Specifically it is used for hormone receptor-positive breast cancer. [8] It has also been used to prevent breast cancer in those at high risk. [8] It is taken orally. [8] Arimidex (Anastrozole) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. 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 is a registered trademark of the AstraZeneca group of companies and is licensed to ANI Pharmaceuticals, Inc. for U.S. sales. 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.