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] 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. 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. Arimidex is an aromatase inhibitor used to treat all stages of hormone receptor-positive breast cancer in postmenopausal women. For the primary endpoints, trial 0030 showed that ARIMIDEX had a statistically significant advantage over tamoxifen (p=0.006) for time to tumor progression; objective tumor response rates were. 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. 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 (anastrozole) is a brand-name prescription drug that’s used for certain types of breast cancer. Learn about side effects, warnings, dosage, and more. Find patient medical information for Anastrozole (Arimidex) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Arimidex (Anastrozole) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources.