Danazol

Danazol is a derivative of the synthetic steroid ethisterone, a modified testosterone, also known as 17-alpha-ethinyl testosterone. 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.