VA Class:HS400
ATC Class:G03XC
Clomiphene citrate is a nonsteroidal compound with both estrogenic and anti-estrogenic properties that is used to induce ovulation in anovulatory women.
Clomiphene citrate is used to induce ovulation in appropriately selected anovulatory women desiring pregnancy. Clomiphene citrate is ineffective in patients with primary pituitary or ovarian failure and is indicated only for patients in whom ovulatory dysfunction has been demonstrated. The drug is not a substitute for appropriate therapy of other conditions which may cause ovulatory dysfunction (e.g., thyroid or adrenal disease). Optimum results with clomiphene therapy are obtained in patients with adequately functioning anterior pituitary gland, adrenals, ovaries, and thyroid. Although better results are usually obtained in patients with adequate serum estrogen concentrations, reduced serum estrogen concentrations do not always preclude successful therapy.
Candidates for clomiphene therapy must be given a complete pelvic examination and endometrial biopsy before each course of treatment and neoplastic lesions must be ruled out. All impediments to achieving ovulation and conception must be excluded or treated before beginning clomiphene citrate therapy. The therapeutic effects of clomiphene citrate are temporary, and the anovulatory pattern usually resumes following discontinuance of therapy or when pregnancy is completed.
Clomiphene citrate has been used in a limited number of patients for the treatment of a variety of menstrual abnormalities†, gynecomastia†, fibrocystic disease of the breast†, oligospermia†, persistent lactation†, endometrial hyperplasia†, endometrial anaplasia†, and regulation of cycles in patients using the rhythm method of contraception†. The drug also has been used in combination with estrogens or menotropins† in patients who are refractory to either drug alone. Efficacy of clomiphene citrate in these conditions has not been established.
Clomiphene citrate is administered orally.
The usual initial dosage of clomiphene citrate used to induce ovulation is 50 mg daily for 5 days. It is important to carefully time the dosage schedule. Therapy may be started at any time in patients who have had no recent uterine bleeding. If progestin-induced bleeding is planned, or if spontaneous uterine bleeding occurs prior to therapy, the regimen should be started on the fifth day of the cycle. Once ovulation has been established, each subsequent course of therapy should be started on the fifth day of the cycle. Although ovulation is slightly more likely to occur with a dosage of 100 mg daily for 5 days, the adverse effects and incidence of multiple ovulations with resulting plural gestations may be expected to increase at this higher dosage.
The majority of the patients who are going to respond to clomiphene citrate will ovulate after the first course of therapy, generally within 5-14 days. If ovulation has not occurred at this time, 100 mg of clomiphene citrate may be administered daily for 5 days, starting as early as 30 days after previous therapy. Dosage should be increased only in those patients who do not respond to the first course of therapy, and dosage should never be increased or extended beyond 100 mg daily for 5 days. Prolonged amenorrhea may be less responsive to clomiphene and may require 2 or more cycles of therapy. Three courses of clomiphene should constitute an adequate therapeutic trial; if ovulatory menses or pregnancy has not occurred at this time, the diagnosis should be reevaluated. The likelihood of conception decreases with each succeeding course of therapy.
Since the relative safety of long-term cyclic therapy with clomiphene has not been conclusively demonstrated, and since the majority of patients will ovulate after 3 courses of therapy, long-term cyclic therapy is not recommended.
The frequency and severity of adverse reactions to clomiphene citrate appear to be dose related and occur most frequently in patients receiving high doses (100 mg or more daily) and/or prolonged therapy.
The most common adverse effects of clomiphene citrate are ovarian enlargement or cyst formation and vasomotor symptoms such as hot flashes. When clomiphene is administered in recommended dosages, abnormal ovarian enlargement is infrequent; however, the usual cyclic variation in ovarian size may be exaggerated and mid-cycle ovarian pain (mittelschmerz) may be accentuated. Ovarian enlargement and cyst formation (usually luteal) may occur more frequently and the luteal phase of the menstrual cycle may be prolonged in patients receiving higher dosages or prolonged administration of the drug. Some patients with polycystic ovary syndrome are unusually sensitive to gonadotropin and may have an exaggerated response to usual doses of clomiphene citrate. Massive ovarian enlargement has been reported rarely. If abnormal enlargement of the ovary occurs during clomiphene therapy, the drug should be discontinued. (See Cautions: Precautions and Contraindications.) Maximal enlargement of the ovary does not occur until several days following discontinuance of clomiphene therapy; however, ovarian enlargement and cyst formation usually regress spontaneously a few days or weeks following discontinuance of the drug. Unless a strong indication for laparotomy exists, most patients with ovarian enlargement or cyst formation should be managed conservatively.
Vasomotor symptoms reported with clomiphene resemble menopausal hot flashes. These effects are usually mild and disappear after clomiphene therapy is discontinued.
Abdominal symptoms or pelvic discomfort including distention, bloating, or pain may occur with clomiphene therapy and may resemble mittelschmerz, premenstrual phenomena, or ovarian enlargement.
Adverse visual symptoms including transient blurring of vision, diplopia, scotomata, phosphenes, or photophobia have occurred in patients receiving clomiphene. These adverse ocular effects appear to be dose related and usually disappear within a few days or weeks following discontinuance of the drug. Visual symptoms seem to result from intensification and prolongation of after-images and often first appear or are accentuated when the patient is exposed to a more brightly-lit environment. Rarely, decreased visual acuity may occur. One patient reportedly developed posterior cortical senile cataracts following clomiphene therapy, but the causal relationship between cataracts and the drug has not been determined. Ophthalmologically definable scotomata and electroretinographic changes in retinal function have also been reported.
Other adverse effects of clomiphene citrate include nausea or vomiting, increased urinary frequency or volume, heavier menses, increased appetite and weight gain, and various dermatologic conditions including urticaria, rash, or allergic dermatitis. Breast discomfort, increased nervous tension, headache, restlessness, insomnia, dizziness, lightheadedness, depression, fatigue, and reversible hair loss may also occur.
Clomiphene citrate has not been reported to produce any clinically important abnormalities in hematologic or renal systems, in protein-bound iodine, or in serum cholesterol when given for short periods; however, following prolonged, continuous administration, elevated concentrations of desmosterol have been reported, indicating a possible interference with cholesterol synthesis.
Increased retention of sulfobromophthalein has occurred during therapy with clomiphene while results of other liver function tests usually have been normal. One case of jaundice due to bile stasis has been reported.
Precautions and Contraindications
Because of possible visual disturbances, dizziness, or lightheadedness, patients receiving clomiphene citrate should be cautioned against performing hazardous tasks requiring mental alertness or physical coordination (e.g., operating machinery, driving a motor vehicle), particularly under conditions of variable lighting. Clomiphene citrate should be used with caution in patients who are unusually sensitive to pituitary gonadotropins (e.g., patients with polycystic ovary syndrome).
Because further enlargement of the ovary may occur, clomiphene citrate should not be given in the presence of an ovarian cyst. Patients should be carefully monitored for signs and symptoms of excessive ovarian stimulation (e.g., pelvic pain) during clomiphene therapy. If ovarian enlargement or cyst development occurs, therapy should be interrupted until the ovaries have returned to pretreatment size, and the dosage or duration of the next course of therapy should be decreased.
If any adverse visual symptoms occur during clomiphene treatment, the drug should be discontinued and a complete ophthalmologic evaluation performed.
Clomiphene citrate is contraindicated in patients with liver disease or in those with a history of liver dysfunction, and clinical evaluation of liver function should always precede therapy. Clomiphene citrate is contraindicated in patients with abnormal uterine bleeding of undetermined origin.
The incidence of multiple ovulations with resulting plural gestations (mostly twins) is increased when conception occurs during a cycle in which clomiphene citrate is administered. Prior to clomiphene citrate therapy, the patient and her male sexual partner should be informed of the possibility and potential risks associated with plural gestation. Simultaneous bilateral tubal pregnancy, an extremely rare form of twin pregnancy, has been reported following combined therapy with clomiphene citrate and chorionic gonadotropin.
Clomiphene citrate is contraindicated during pregnancy. The drug has been shown to be teratogenic in rats and rabbits. Congenital abnormalities (e.g., Down's syndrome, exstrophy, club foot, tibial torsion, blocked tear duct, hemangioma, neural tube defects) have been reported in infants conceived following clomiphene citrate therapy. These effects have not been directly attributed to the drug and the manufacturers state that the cumulative rate of congenital abnormalities does not exceed that reported in the general population. To avoid inadvertent clomiphene citrate administration during early pregnancy, the patient should be carefully observed to determine if ovulation occurs. The basal body temperature should be recorded throughout all treatment cycles, and clomiphene therapy should be discontinued if pregnancy is suspected. If the basal body temperature is biphasic and not followed by menses, the possibility of an ovarian cyst and/or pregnancy should be excluded and subsequent clomiphene therapy should be delayed until a correct diagnosis has been made.
Clomiphene citrate has both estrogenic and anti-estrogenic properties, but its precise mechanism of action in inducing ovulation in anovulatory females has not been determined. The drug appears to stimulate the release of the pituitary gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH), which results in development and maturation of the ovarian follicle, ovulation, and subsequent development and function of the corpus luteum. Gonadotropin release may result from direct stimulation of the hypothalamic-pituitary axis or from a decreased inhibitory influence of estrogens on the hypothalamic-pituitary axis by competing with the endogenous estrogens of the uterus, pituitary, or hypothalamus. Clomiphene citrate may also directly affect the biosynthesis of ovarian hormones.
Clomiphene citrate has no progestational, androgenic, or anti-androgenic effects and does not appear to interfere with pituitary-adrenal or pituitary-thyroid functions.
Clomiphene citrate is readily absorbed from the GI tract following oral administration. In studies using radiolabeled clomiphene citrate, blood concentrations of the drug were low and exhibited interpatient variation.
Clomiphene citrate appears to have a half-life of about 5 days; however, following oral administration of radiolabeled drug, radioactivity was present in feces for up to 6 weeks. Although the exact metabolic fate of clomiphene citrate is not clearly established, the drug appears to be metabolized in the liver. The drug and/or its metabolites are excreted principally in feces via biliary elimination. Limited studies suggest that the drug is excreted slowly from a sequestered enterohepatic recirculation pool or may be stored in body fat and subsequently released slowly.
Clomiphene citrate is a nonsteroidal triarylethylene compound that is used to induce ovulation in anovulatory women. Clomiphene citrate is structurally related to chlorotrianisene (no longer commercially available in the US). Clomiphene citrate occurs as a white to pale yellow, crystalline powder and is sparingly soluble in water and in alcohol.
Clomiphene citrate tablets should be protected from light and stored in well-closed containers at a temperature less than 40°C, preferably between 15-30°C.
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.
Routes | Dosage Forms | Strengths | Brand Names | Manufacturer |
|---|---|---|---|---|
Oral | Tablets | 50 mg* | Clomid® (scored) | |
Serophene® (scored) |
* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name