 Ethisterone was followed by the improved and much more widely used and known progestin norethisterone in 1957.Ethisterone was used in the treatment of gynecological disorders such as irregular menstruation, amenorrhea, and premenstrual syndrome.Ethisterone was available in the form of 5, 10, and 25 mg oral and sublingual tablets, as well as 50 , 100 , and 250 mg oral capsules.