A 55-year-old woman is noted to be taking tamoxifen to help with breast cancer. She also complains of vaginal bleeding. Wof is the best explanation for vaginal bleeding

Selective estrogen receptor modulators (SERMs) Tamoxifen citrate Mech of action:- It acts as potent estrogen antagonist in breast carcinoma cells, blood vessels and at some peripheral sites, but as paial agonist in uterus, bone, liver and pituitary. Inhibition of human breast cancer cells and hot flushes reflect antiestrogenic action, while the weak estrogen agonistic action manifests as stimulation of endometrial proliferation, lowering of Gn and prolactin levels in postmenopausal women as well as improvement in their bone density. Side effects:- Hot flushes, vomiting, vaginal bleeding, vaginal discharge, menstrual irregula- rities are the side effects. Increased risk of venous thromboembolism is due to estrogenic action on clotting mechanism. Dermatitis, anorexia, depression, mild leucopenia and ocular changes are infrequent. Ref:- kd tripathi; pg num:-313