Raloxifene

Raloxifene is a selective estrogen receptor modulator (SERM) and hence is a mixed agonist and antagonist of the estrogen receptor (ER) in different tissues.<ref name="a4">[https://www.drugs.com/monograph/raloxifene.html|"Raloxifene Hydrochloride Monograph for Professionals".] Drugs.com. American Society of Health-System Pharmacists. Retrieved 22 March 2019.</ref> It has estrogenic activity in some tissues, such as bone and the liver, and antiestrogenic activity in other tissues, such as the breasts and uterus.<ref name="a4">[https://www.drugs.com/monograph/raloxifene.html|"Raloxifene Hydrochloride Monograph for Professionals".] Drugs.com. American Society of Health-System Pharmacists. Retrieved 22 March 2019.</ref> Its affinity (Kd) for the ERα is approximately 50 pM, which is similar to that of estradiol.[16] Relative to estradiol, raloxifene has been reported to possess about 8 to 34% of the affinity for the ERα and 0.5 to 76% of the affinity for the ERβ.[22][23] Raloxifene acts as a partial agonist of the ERα and as a pure antagonist of the ERβ.[24][25] In contrast to the classical ERs, raloxifene is an agonist of the G protein-coupled estrogen receptor (GPER) (EC50 = 10–100 nM), a membrane estrogen receptor.[26][27]