List of products in the National Drug Code with proprietary name . This medication is used to treat certain types of breast cancer (such as hormone-receptor-positive breast cancer) in women after menopause. Exemestane is also used to help prevent the cancer from returning. Some breast cancers are made to grow faster by a natural hormone called estrogen. Exemestane decreases the amount of estrogen the body makes and helps to slow or reverse the growth of these breast cancers. Exemestane is usually not used in women of childbearing age.