Anastrozole is a medication primarily used to treat certain types of breast cancer in postmenopausal women. It works by lowering the levels of estrogen in the body, which can help slow or stop the growth of hormone-sensitive tumors. Anastrozole is often prescribed after surgery or radiation therapy to reduce the risk of cancer recurrence. This drug belongs to a class of medications known as aromatase inhibitors. It is typically taken as a daily pill and may be part of a broader treatment plan that includes other therapies. Common side effects can include hot flashes, joint pain, and fatigue.