Letrozole wani ɓangare ne na sabon ƙarni na masu hana aromatase masu zaɓaɓɓu kuma shi ne abin da aka samo asali na benzotriazole.Letrozole yana hana aromatase don rage matakan estrogen, don haka yana hana estrogen daga haɓakar haɓakar ƙwayar cuta.Ayyukansa a cikin vivo yana da ƙarfi sau 150-250 fiye da na ƙarni na farko na aromatase inhibitor Amarante.Kamar yadda yake da zaɓi sosai, ba zai tasiri glucocorticoid ba, mineralocorticoid da ayyukan thyroid;ko da a high dosages, shi ba zai da wani inhibiting effects a kan adrenal corticosteroid mugunya, ba shi babban magani index.