Selective estrogen receptor modulators (SERM)

Nonsteroidal synthetic agents
Selective estrogen receptor modulators, which are sometimes referred to as partial estrogen agonist/antagonists
Modulates activity of estrogen receptors
Unique profile of aginistic/antagonistic actions(agonist in bone and CVS but antagonist in endometrium and breast)
statistically significant improvement in bone mineral density
extreme caution for perimenopausal because the drug is contraindicated in pregnancy

good choice of therapy for women with a history of breast or uterine cancer or for women with concerns about taking estrogen
Adverse effects are vasomotor symptoms
Other side effects of leg cramps and venous thrombohemolytic events have been reported.
It may also be a better choice of therapy for women with severe gastrointestinal symptoms and for those who have difficulty tolerating the bisphosphonates.