Selective estrogen receptor modulator. Estrogen agonist in bone and estrogen receptor antagonist in breast and uterine tissue.Indicated in treating osteoporosis and preventing breast cancer. Raloxifene does not alter prolactin secretion in premenopausal women but increases levels of estradiol and sex-hormone binding globulin (BGSH). At last update no published data on excretion in breast milk were found.Pharmacokinetic data (large volume of distribution, moderately high molecular weight and high percentage of protein binding) make it unlikely milk passage of significant amounts.Low oral bioavailability hinders the passage into infant plasma from ingested milk except in preterm neonates and immediate neonatal period, because an increased intestinal permeability can appear. Although short-term treatments may be of low risk during breastfeeding, the anti-estrogenic effect on breast tissue, a prolonged use is not recommended.