Enzalutamide is used to treat prostate cancer. This medication belongs to a class of drugs known as anti-androgens (anti-testosterone). It works by blocking the effects of testosterone to slow the growth and spread of prostate cancer. Enzalutamide is used to treat prostate cancer. This medication belongs to a class of drugs known as anti-androgens (anti-testosterone). It works by blocking the effects of testosterone to slow the growth and spread of prostate cancer.