Clomid® (clomiphene citrate)

Clomid is a drug of considerable pharmacologic potency. With carefulselection and proper management of the patient, Clomid has beendemonstrated to be a useful therapy for the anovulatory patientdesiring pregnancy.

Clomiphene citrate is capable of interacting withestrogen-receptor-containing tissues, including the hypothalamus,pituitary, ovary, endometrium, vagina, and cervix. It may compete withestrogen for estrogen-receptor-binding sites and may delayreplenishment of intracellular estrogen receptors. Clomiphene citrateinitiates a series of endocrine events culminating in a preovulatorygonadotropin surge and subsequent follicular rupture. The firstendocrine event in response to a course of clomiphene therapy is anincrease in the release of pituitary gonadotropins. This initiatessteroidogenesis and folliculogenesis, resulting in growth of theovarian follicle and an increase in the circulating level of estradiol.Following ovulation, plasma progesterone and estradiol rise and fall asthey would in a normal ovulatory cycle.

Available data suggest that both the estrogenic and antiestrogenicproperties of clomiphene may participate in the initiation ofovulation. The two clomiphene isomers have been found to have mixedestrogenic and antiestrogenic effects, which may vary from one speciesto another. Some data suggest that zuclomiphene has greater estrogenicactivity than enclomiphene.

Clomiphene citrate has no apparent progestational, androgenic, orantiandrogenic effects and does not appear to interfere withpituitary-adrenal or pituitary-thyroid function.

Although there is no evidence of a "carryover effect" of Clomid,spontaneous ovulatory menses have been noted in some patients afterClomid therapy.