Cyproterone acetate

Cyproterone acetate (brand name Androcur among others) is a steroidal antiandrogen and progestogen. It has potent antigonadotropic effects via activation of the progesterone receptor and is able to reduce testosterone levels by up to 70 to 80% at dosages that are sufficiently high (e.g., approximately 25 to 100 mg/day). In addition to its antigonadotropic effects, it also directly binds to and blocks the androgen receptor, although with very weak partial agonist activity. The drug also has weak glucocorticoid effects. It can cause side effects such as neuropsychiatric side effects like depression, anxiety, fatigue, and suicidal thoughts, elevated liver enzymes, and vitamin B12 deficiency. In addition, rarely, it can cause liver damage and failure, excessively high prolactin levels, meningiomas, and blood clots.