Action And Clinical Pharmacology: Chorionic gonadotropin is a glycoprotein substance, with a molecular weight of approximately 38 600, secreted by the placenta and obtained from the urine of pregnant women. It is composed of nonidentical and noncovalently linked a and b subunits. The a subunit of CG is essentially identical to the a subunits of the human pituitary gonadotropins, luteinizing hormone and follicle-stimulating hormone, as well as to the a subunit of human TSH; however, the b subunit of CG differs in amino acid sequence from these other hormones.
Chorionic gonadotropin occurs as a white or practically white, amorphous powder and is freely soluble in water.
The action of HCG is virtually identical to that of pituitary LH, although HCG appears to have a small degree of FSH activity as well. It stimulates production of gonadal steroid hormones by stimulating the interstitial cells (Leydig cells) of the testis to produce androgens and the corpus luteum of the ovary to produce progesterone.
Androgen stimulation in the male leads to the development of secondary sex characteristics and may stimulate testicular descent when no anatomical impediment to descent is present. This descent may be reversible, on extremely rare occasions, when HCG is discontinued.
HCG has no known effect on fat mobilization, appetite or sense of hunger, or body fat distribution.
Following i.m. administration, an increase in serum chorionic gonadotropin concentrations may be observed within 2 hours. Peak concentrations occur within 6 hours and persist for approximately 36 hours. Serum chorionic gonadotropin levels begin to decline at 48 hours reaching undetectable levels after 72 hours. Chorionic gonadotropin is distributed primarily in the testes and ovaries of the male and female respectively, with small amounts possibly distributing into the proximal tubules of the renal cortex.
Blood levels of chorionic gonadotropin decline in a biphasic manner. The initial phase half-life has been reported between 5.6 and 11 hours, whereas the terminal phase half-life has been reported between 23 and 37.2 hours. Following i.m. administration of therapeutic doses, approximately 10 to 12% of the dose is excreted in the urine within 24 hours.
Indications And Clinical Uses: Prepubertal cryptorchidism not due to anatomical obstruction. In general, HCG is thought to induce testicular descent in situations when descent would have occurred at puberty. HCG thus may help predict whether or not orchiopexy will be needed in the future. Descent following HCG administration is usually permanent.
Selected cases of hypogonadotropic hypogonadism (hypogonadism secondary to a pituitary deficiency) in males.
Induction of ovulation and pregnancy in the anovulatory, infertile woman in whom the cause of anovulation is secondary and not due to primary ovarian failure, and who has been appropriately pretreated with human menotropins.
Note: HCG has not been demonstrated to be effective adjunctive therapy in the treatment of obesity. There is no substantial evidence that it increases weight loss beyond that resulting from caloric restriction, that it causes a more attractive or “normal” distribution of fat, or that it decreases the hunger and discomfort associated with calorie-restricted diets.
Contra-Indications: Precocious puberty, prostatic carcinoma or other androgen-dependent neoplasm, prior allergic reaction to HCG. tag_WarningWarnings
Manufacturers’ Warnings In Clinical States: HCG should be used in conjunction with human menopausal gonadotropins only by physicians experienced with infertility problems who are familiar with the criteria for patient selection, contraindications, warnings, precautions, and adverse reactions described in the package insert for menotropins.
The principal serious adverse reactions during this use are: ovarian hyperstimulation, a syndrome of sudden ovarian enlargement, ascites with or without pain, and/or pleural effusion; rupture of ovarian cysts with resultant hemoperitoneum; multiple births; and arterial thromboembolism.
Precautions: Induction of androgen secretion by HCG may induce precocious puberty in patients treated for cryptorchidism. Therapy should be discontinued if signs of precocious puberty occur.
Since androgens may cause fluid retention, HCG should be used with caution in patients with cardiac or renal disease, epilepsy, migraine, or asthma.
Adverse Reactions: Headache, irritability, restlessness, depression, fatigue, edema, precocious puberty, gynecomastia, pain at the injection site.
Ovarian cancer has been reported in a very small number of infertile women who have been treated with fertility drugs. A causal relationship between treatment with fertility drugs and ovarian cancer has not been established.
Dosage And Administration: For i.m. use only after reconstitution of the dry powder with the sterile diluent. Although the dosage regimen will depend upon the indication, the patient’s age and weight, and the prescriber’s preference, the following regimens have been advocated by various authorities.
Males: Prepubertal Cryptorchidism Not Due To Anatomical Obstruction: 4 000 USP units, 3 times weekly, for 2 to 3 weeks, or 1 000 USP units, 3 times weekly for 6 to 8 weeks. The dosage schedule may vary to some extent, depending upon the age when treatment is given. If the dosage is adequate, there will usually be some indication, following one such course of therapy, whether descent will occur or surgery be required.
A therapeutic trial with chorionic gonadotropin may constitute a valuable diagnostic aid to determine the need for surgery. Lack of response is usually an indication of anatomic obstruction. Furthermore, when surgery is required, the preliminary treatment may facilitate the procedure by increasing the size of the testes and the length of the cords. Postoperative gonadotropic therapy has also been suggested to prevent retraction of testes.
Age of Initiation of Treatment: Various ages ranging from early childhood to immediately before expected puberty have been suggested. The average appropriate age, however, appears to be 12 years.
Selected Cases of Hypogonadotropic Hypogonadism in Males: 4 000 to 5 000 USP units 3 times weekly for 6 to 8 weeks with a rest period of 2 to 3 weeks between courses of therapy.
Females: Induction of ovulation and pregnancy in the anovulatory infertile woman in whom the cause of anovulation is secondary and not due to primary ovarian failure and who has been appropriately pretreated with human menotropins (see prescribing information for menotropins for dosage and administration for that drug product).
5 000 to 10 000 USP units 1 day following the last dose of menotropins. (A dosage of 10 000 USP units is recommended in the labeling of menotropins.)
Directions for Reconstitution: Reconstitute chorionic gonadotropin for injection to the desired concentration by addition of the required amount of the solvent supplied. Remove 1 to 10 mL of the solvent and add to the vial with the lyophilized powder; agitate gently until the powder is completely dissolved.
When reconstituted with 10 mL of the solvent, the concentration of chorionic gonadotropin is 1 000 USP units/mL. The solvent contains benzyl alcohol 0.9%.
Availability And Storage: Each package contains 2 vials: one multidose vial of Pregnyl 10 000 USP units plus 1 vial of 10 mL sterile Pregnyl solvent. Each vial of Pregnyl contains: sterile lyophilized human chorionic gonadotropin 10 000 USP units. Nonmedicinal ingredients: dibasic sodium phosphate anhydrous (pH may have been adjusted with sodium hydroxide and/or phosphoric acid) and monobasic sodium phosphate monohydrate. Each vial of Pregnyl solvent contains: Bacteriostatic Water for Injection 10 mL, benzyl alcohol 0.9%, sodium chloride 0.56% and trace amounts of sodium hydroxide and/or hydrochloric acid.
Store at 15 to 30°C. Reconstituted solution is stable for 30 days when refrigerated (2 to 8°C).
PREGNYL® Organon Chorionic Gonadotropin Gonadotropin