Selective Estrogen Receptor Modulators

Selective estrogen receptor modulators are utilized for treatment of a variety of conditions.  Each drug interacts with estrogen receptors differently, which results in the intended therapeutic effect. For example, clomiphene is a partial estrogen receptor agonist that blocks negative feedback of estrogens to the hypothalamus, which in turn, results in release of FSH, LH, and GnRH and stimulation of ovulation.  Other drugs in this class are used for the treatment of breast cancer by blocking estrogen receptors in breast tissue.  Raloxifene has estrogen agonist effects in bone, which leads to its indication for osteoporosis.

Class Drugs

• Clomiphene

• Fulvestrant

• Ospemifene

• Raloxifene

• Tamoxifen

• Toremifene

Class Mechanism of Action

Interacts with estrogen receptors to mediate effects

• Raloxifene, Tamoxifen, and Toremifene have similar properties

• See individual drugs for mechanism of action

Class Applications

See individual drugs

Class Adverse Effects

See individual drugs

Drug Table

Drug Name	Application	Comments	Image
Clomiphene	Stimulation of ovulation in infertility	Mechanism; Partial estrogen receptor agonist interfering with negative feedback of estrogens on hypothalamus, which results in increased release of GnRH, FSH, and LH; Adverse Effects; Risk of multiple gestation	"Claw" "Fiend"
Fulvestrant	Hormone positive metastatic breast cancer	Mechanism; Competitive antagonist of estrogen receptors in breast tissue; Adverse Effects; Hot flashes	"Full" "Vest" "Rant
Ospemifene	Dyspareunia		"Osprey" "Fiend"
Raloxifene	Osteoporosis; Treatment of breast cancer; Adjuvant therapy for breast cancer; Breast cancer prophylaxis	Mechanism; -Competitive antagonist of estrogen receptors in breast tissue; -Estrogen agonist in bone; -Estrogen antagonist in endometrium (unlike tamoxifen, does not increase endometrial cancer risk); Adverse Effects; -Nausea; -Hot flashes	"Rolex" "Fiend"
Tamoxifen	Treatment of advanced breast cancer	Mechanism; Competitive antagonist of estrogen receptors in breast tissue; Estrogen agonist in endometrium; Adverse Effects; -Nausea; -Hot flashes; -Increased risk of endometrial cancer, endometrial hyperplasia	"Tampax" "Fiend"
Toremifene	Treatment and prevention of osteoporosis in postmenopausal women; Breast cancer prophylaxis	Mechanism; -Competitive antagonist of estrogen receptors in breast tissue; -Estrogen agonist in bone, increases bone density; Adverse Effects; Hot flashes	"Tore Me" "Fiend"