Aromatase inhibitor

Aromatase inhibitors, which inhibit the enzyme aromatase used biologically to produce estrogens, inhibit the biosynthetic production of estrogen steroids. Because of this action, these inhibitors are sometimes used to treat cancerous tumors, which are estrogen-sensitive, especially breast cancer in postmenopausal women. At present, three AIs are approved by the FDA :

• anastrazole (Arimidex®)
• exemestane (Aromasin®)
• letrozole (Femara®)