Chorionic gonadotropin alfa

Choriogonadotropin alfa is a synthetic form of human chorionic gonadotropin (hCG), a hormone produced during pregnancy.

Use and indications

Choriogonadotropin alfa is mainly used to treat infertility. It is prescribed to women who do not ovulate due to polycystic ovary syndrome (PCOS), hypothalamic amenorrhea, or other conditions. It is also used to stimulate ovulation in women undergoing in vitro fertilization (IVF) or intrauterine insemination (IUI).

This agent is administered by injection under the skin and is usually sold in the form of pre-filled pens.

History

In the 1930s, the hormone hCG was discovered and has since been used to treat infertility. It was largely replaced by the development of choriogonadotropin alfa. The first approval of choriogonadotropin alfa by the U.S. Food and Drug Administration (FDA) was in 2000.

Pharmacology and mechanism of action

Human chorionic gonadotropin interacts with the LHCG receptor of the ovary and promotes the maintenance of the corpus luteum in early pregnancy. This allows the corpus luteum to secrete the hormone progesterone during the first trimester. Progesterone enriches the uterus with a thick layer of blood vessels and capillaries to supply the growing fetus. Because of its similarity to LH, hCG can promote ovulation in the ovaries and testosterone production in the testes, as well as the production of LH and FSH.

Choriogonadotropin alfa, due to its strong structural similarity, stimulates the production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones play a critical role in the production of eggs and sperm. In women, LH and FSH stimulate the growth of the follicles that contain the eggs. In men, LH and FSH stimulate the production of testosterone and the growth of the testes.

Pharmacokinetics

Absorption after administration is rapid and the mean absolute bioavailability after subcutaneous injection in healthy female patients is approximately 40%. One-tenth of the dose is excreted in the urine. The mean terminal half-life is approximately 29 hours.

Drug Interactions

No interactions with other drugs are known.

Contraindications and precautions

Choriogonadotropin alfa should not be used

• if there is an allergy to the active substance
• in case of severe phlebitis or blood clots in the veins
• if ovarian, uterine or breast cancer has been diagnosed
• in case of enlargement of the ovaries or cysts of the ovaries filled with fluid or semisolid material
• in case of unexplained vaginal bleeding
• when normal pregnancy is impossible, such as during menopause or abnormalities of the reproductive organs
• when there is a tumor in the hypothalamus or pituitary gland

Special precautions and warnings:

• The causes of infertility should be determined by an experienced physician before starting treatment
• The risk for ovarian hyperstimulation syndrome (OHSS) may increase with the use of this agent
• The risk of multiple pregnancies and associated complications and birth defects is increased with artificial insemination
• Women with damaged fallopian tubes have an increased risk of extrauterine pregnancy being studied
• The risk of miscarriage is higher with artificial insemination or stimulation of the ovaries to produce eggs than with normal pregnancies
• Increased caution is needed in those with blood clotting problems or an increased risk of blood clots
• Women who have undergone multiple infertility treatments may be at increased risk for benign or malignant tumors of the reproductive organs
• A pregnancy test after using choriogonadotropin alfa may give a false-positive result

Side effects

The use of choriogonadotropin alfa may cause serious side effects. These include:

• Allergic reactions. Symptoms of an allergic reaction may include skin rashes, irregular heartbeat, swelling of the tongue and throat, and breathing problems
• severe abdominal pain along with vomiting, nausea and bloated abdomen. This may indicate ovarian cysts.
• Blood clotting disorders

Common side effects may include:

• Diarrhea
• pain and reactions at the injection site
• Headache

Pregnancy and breastfeeding

Choriogonadotropin alfa should not be used during pregnancy and breastfeeding.