What Casodex is and what it is used for. Casodex contains a medicine called bicalutamide. This belongs to a group of medicines called 'anti-androgens'. Casodex is used to treat prostate cancer. It works by blocking the effects of male hormones such as testosterone When is the best time to take Casodex? It is best to take this medicine at the same time each day, in the morning or in the evening.