Exemestane (formerly also known as FCE24304, PNU155971; FCE 24304; EXE), a drug used in ER-positive breast cancer, is a synthetic and potent aromatase inhibitor, which inhibits human placental and rat ovarian aromatase with IC50 of 30 nM and 40 nM, respectively.

Letrozole (formerly known as CGS-20267; trade name: Femara; Letoval) is a third generation, nonsteroidal inhibitor of aromatase with IC50 of 0.07-20 nM in cell-free assays and has anticancer activities.

Aminoglutethimide (also known as BA-16038, NSC-330915) is an an anticancer drug that acts as a nonsteroidal aromatase inhibitor with IC50 of 10 μM.

Formestane (formerly also known as CGP-32349, NSC 282175) is a second generation, selective, orally bioactive and synthetic steroidal aromatase inhibitor with an IC50 of 80 nM.

Anastrozole (formerly known as ZD-1033) is a potent, third-generation nonsteroidal and selective inhibitor of aromatase with an IC50 of 15 nM for inhibiting human placental aromatase.

Fadrozole (CGS 16949A) is a highly potent and selective nonsteroidal aromatase inhibitor (IC50 of 6.4 nM) with potential antineoplastic activity.