Danazol

Danazol is a derivative of the synthetic steroid ethisterone that suppresses the production of gonadotropins and has some weak androgenic effects. Before becoming available as a generic drug, danazol was marketed as Danocrine in the United States. It was approved by the US Food and Drug Administration (FDA) as the first drug to specifically treat endometriosis in the early 1970s. Although effective for endometriosis, its use is limited by its masculinizing side-effects. Its role as a treatment for endometriosis has been largely replaced by the GnRH agonists.

Chemistry

The agent is fat-soluble. It is an isoxazole of testosterone with isolated weak androgenic activity and no estrogenic or progestagenic effects.

Mechanism of action

Danazol exhibits hypoestrogenic, hyperandrogenic effects that cause atrophy of the endometrium, which can alleviate the symptoms of endometriosis.

Danazol prevents ovulation by suppressing the increase of luteinizing hormone during the middle of the menstrual cycle. Danazol inhibits ovarian steroidogenesis resulting in decreased secretion of estradiol and may increase androgens. Danazol displaces testosterone from sex hormone-binding globulin (SHBG), displacing it and increasing serum testosterone levels. Danazol also directly stimulates androgen and progesterone receptors.