A 17-oxo steroid that is androst-4-ene-3,17-dione in which the hydrogen at position 4 is replaced by a hydroxy group. Formestane was the first selective, type I steroidal aromatase inhibitor, suppressing oestrogen production from anabolic steroids or prohormones. It was formerly used in the treatment of oestrogen-receptor positive breast cancer in post-meopausal women. As it has poor oral bioavailability, it had to be administered by (fortnightly) intramuscular injection. It fell out of use with the subsequent development of cheaper, orally active aromatase inhibitors. Formestane is listed by the World Anti-Doping Agency as a substance prohibited from use by athletes.
belongs to the class of organic compounds known as androgens and derivatives. These are 3-hydroxylated C19 steroid hormones. They are known to favor the development of masculine characteristics. They also show profound effects on scalp and body hair in humans.
