dear madam Tamoxifen is used to treat breast cancer and is It is a selective estrogen-receptor modulator that works both by decreasing factors that increase the growth of breast cells and increasing factors that decrease the growth of breast cells. it is typically taken for five years. A beneficial side effect of tamoxifen is that it prevents bone loss by acting as an estrogen receptor agonist (i.e., mimicking the effects of estrogen) in this cell type. Therefore, by inhibiting osteoclasts, it prevents osteoporosis. endometriosis has been reported in some women It does show evidence of reduced cognition, a major side effect of tamoxifen, and semantic memory scores, While evista :raloxifene) affects the cycle of bone formation and breakdown in the body, and reduces loss of bone tissue. Evista is used to treat or prevent osteoporosis in postmenopausal women. ... Evista is not a cancer medication and will not treat breast cancer. Now that i have explained the side effects and effects of both you can draw your conclusions. The use of medication is primarily aimed at reduction of mortality and morbidity, you doctor keeping in mind your longevity and effectiveness needs must have weighed the pro and cons of the medication before putting you on them. it will be advisable to discuss it out with your treating team and get the right picture as we here can only infer so much.