Gestrinone

Gestrinone, sold under the brand names Dimetrose and Nemestran among others, is a medication which is used in the treatment of endometriosis. It has also been used to treat other conditions such as uterine fibroids and heavy menstrual bleeding and has been investigated as a method of birth control. Gestrinone is used alone and is not formulated in combination with other medications. It is taken by mouth or in through the vagina. Side effects of gestrinone include menstrual abnormalities, estrogen deficiency, and symptoms of masculinization like acne, seborrhea, breast shrinkage, increased hair growth, and scalp hair loss, among others. Gestrinone has a complex mechanism of action, and is characterized as a mixed progestogen and antiprogestogen, a weak androgen and anabolic steroid, a weak antigonadotropin, a weak steroidogenesis inhibitor, and a functional antiestrogen. Gestrinone was introduced for medical use in 1986. It has been used extensively in Europe but appears to remains marketed only in a few countries throughout the world. The medication is not available in the United States. Due to its anabolic effects, the use of gestrinone in competition has been banned by the International Olympic Committee. Gestrinone is approved for and used in the treatment of endometriosis. It is described as similar in action and effect to danazol, which is also used in the treatment of endometriosis, but is reported to have fewer androgenic side effects in comparison. Gestrinone has also been used to shrink uterine fibroids and to reduce menorrhagia. Due to its antigonadotropic effects and ability to inhibit ovulation, gestrinone has been studied as a method of hormonal birth control in women. Large studies across thousands of menstrual cycles have found it to be effective in preventing pregnancy. However, although effective, the pregnancy rate in the largest study conducted was 4.6 per 100 woman-years, which is too high of a failure rate for the medication to be recommended as a safe method of birth control.