Tamoxifen is a (SERM) selective estrogen receptor modulator that acts as an antagonist at breast tissue and an agonist at the endometrium and bone. Risks of its use include the development of endometrial hyperplasia endometrial cancer, and venous thromboembolism.
AKA: " competitive inhibitor of estradiol binding to its receptor."
submitted by โcassdawg(1780)
One of the more important things to know about tamoxifen is that it is an estrogen antagonist in the breast but agonist in the uterus and bone. (FA2020 p443 and p656). This causes increased risk of endometrial hyperplasia and cancer on tamoxifen.
NOTE: Even though it is agonist in bone (technically), it is not used commonly for postmenopausal therapy for osteoporosis due to the agonist activity in the uterus. Raloxifene is used instead, which is agonist at bone but antagonist at breast and uterus. Raloxifene is not as strong as an antagonist at breast so it is not used for breast cancer treatment.