COSAMIDE 50 is used in combination with other medicines to treat advanced prostate cancer. COSAMIDE 50 is an anti-androgen medicine. Androgens such as testosterone are natural male sex hormones. In some types of prostate cancer, androgens may help the cancer cells to grow. COSAMIDE 50 interferes with some of the actions of these hormones. COSAMIDE 50 should only be taken by men.