Phencyclidine (PCP) Profile Phencyclidine (PCP) is a synthetic dissociative drug originally developed as a general anesthetic. The effects of dissociative drugs like PCP include feelings of detatchment from the environment and self.In its pure form, PCP is a white crystalline powder that dissolves easily in water or alcohol. As a liquid, it is clear, yellow, or tan and often is sold in vanilla extract bottles.CP’s Effects on the Brain PCP disrupts the functioning of receptors for the neurotransmitter glutamate, which plays a major role in the perception of pain as well as in learning, memory, and emotion. It also influences the actions of the neurotransmitter dopamine, which causes the euphoria associated with drug use.