Estrogen clomiphene

For the purposes of this article, antiestrogens are compounds that counteract the biological activity of estrogens at the receptor level. In the late 1970s, there were no steroidal antiestrogens in widespread clinical use. Clomiphene [911 -45-5]( ) and tamoxifen/7(954(9-25 -/7(9) were nonsteroidal antiestrogens that had been employed for the treatment of female infertility and breast cancer, respectively. 

As noted previously, triarylethylenes substituted by a basic group, such as clomiphene, exhibit estrogen antagonist activity. Formal cyclization of that molecule to a more steroid-like, rigid conformation enhances potency in this series. 

Clomiphene (Clomid) is a synthetic nonsteroidal compound that binds to estrogen receptors, decreasing the amount of available estrogen receptors and causing the anterior pituitary to increase secretion of FSH and LH. It is used to induce ovulation in anovulatory (nonovulating) women. 

Some tumors are estrogen-dependent and the use of an antiestrogen has therapeutic value. One such antineoplastic agent appears to be patterned after clomiphene. Complex aryl ketone 204 is treated with phenyl magnesium chloride and the resulting tertiary... 

The answer is b. (Hardman, pp 1424-1425. Katzung, pp 699-700J Clomiphene binds the estrogen receptor It typically acts as a partial antag-... 

Aromatase inhibitors (including anastrozole, letrozole, aminoglutethimide, exemestane, formestane, testolactone), selective estrogen receptor modulators—SERMs (including raloxifene, tamoxifen, toremifene), clomiphene, cyclofenil, fulvestrant Diuretics, amiloride, bumetanide, canrenone, chlorthalidone, etacrynic acid, furosemide, indapamide, metolazone, spironolactone, thiazides, triamterene... 

Tamoxifen, clomiphene, and raloxifene are orally active. The primary route of excretion of all three drugs is in the feces. The undesirable effects common to all three of these SERMs are increased frequency of hot flashes and increased risk of thromboembolism. Both effects are attributable to their estrogenic activity. 

Therapeutically, gonadotropins are used to induce ovulation in infertile women. The antiestrogens clomiphene (5.37) and tamoxifen (5.38) are also used for this purpose since they counteract the ovulation-inhihitory effect of estrogens. Pregnancy tests depend on the presence of an increased hCG concentration in the urine after fertilization. 

Clomiphene is an older partial agonist, a weak estrogen that also acts as a competitive inhibitor of endogenous estrogens (Figure 40-5). It has found use as an ovulation-inducing agent (see below). 

Clomiphene citrate, a partial estrogen agonist, is closely related to the estrogen chlorotrianisene (Figure 40-3). This compound is well absorbed when taken orally. It has a half-life of 5-7 days and is excreted primarily in the urine. It exhibits significant protein binding and enterohepatic circulation and is distributed to adipose tissues. 

Clomiphene is a partial agonist at estrogen receptors. The estrogenic agonist effects are best demonstrated in animals with marked gonadal... 

Clomiphene is a very weak non-steroidal estrogen it blocks the feedback effect of endogenous estrogens on the pituitary, promoting the further secretion of gonadotropins. The primary use of clomiphene in women is in the induction of ovulation. In men, it has been used to treat infertility in view of its ability to increase endogenous production of testosterone (1). 

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