ATC Group: L02A Hormones and related agents

Buserelin is a synthetic peptide. It is a superactive analogue of natural gonadotrophin releasing hormone (gonadorelin, LHRH or GNRH). After an initial stimulation of gonadotrophin release, it down-regulates the hypothalanic-pituitary-gonadal axis.

Diethylstilbestrol is a synthetic nonsteroidal estrogen, that was widely used to prevent potential miscarriages by stimulating the synthsis of estrogen and progesterone in the placenta. It was also used for the treatment of symptoms arising during menopause and following ovariectomy and for senile vaginitis and vulvar dystrophy. Diethylstilbestrol was used as a postcoital emergency contraceptive (morning-after pill). It has also been used for the prevention of postpartum breast engorgement, for dysfuctional menstrual cycles and for the treatment of female hypogonadism. Diethylstilbestrol is now rarely used to treat prostate cancer and occacionally in postmenopausal women with breast cancer because of its side-effects.

Ethinylestradiol is chemically and biologically identical to endogenous human oestradiol. It substitutes for the loss of estrogen production in menopausal women, and alleviates menopausal symptoms. Estrogens prevent bone loss following menopause or ovariectomy.

Goserelin is a synthetic analogue of naturally occurring LHRH. On chronic administration goserelin results in inhibition of pituitary LH secretion leading to a fall in serum testosterone concentrations in males and serum estradiol concentrations in females.

Histrelin is a gonadotropin releasing hormone (GnRH) agonist and an inhibitor of gonadotropin secretion when given continuously. It is indicated for the treatment of children with central precocious puberty (CPP). However, continuous administration of histrelin acetate causes a reversible down-regulation of the GnRH receptors in the pituitary gland and desensitization of the pituitary gonadotropes.

Leuprorelin is inactive when given orally due to poor membrane permeability and an almost complete inactivation by intestinal proteolytic enzymes. Leuprorelin has potent LHRH agonist properties when given during short-term and intermittent therapy, however, when administered in a continuous, nonpulsatile manner, LHRH analogs induce inhibition of gonadotropin secretion and suppression of testicular steroidogenesis.

Medroxyprogesterone acetate exerts anti-oestrogenic, anti-androgenic and antigonadotrophic effects.

Megestrol possesses pharmacological properties similar to those of natural progesterone. Megestrol acetate is a potent progestogen that exerts significant anti-oestrogenic effects. It has no androgenic or oestrogenic properties.

Triptorelin is a decapeptide analogue of GnRH which initially stimulates release of pituitary gonadotropins.