Phencyclidine (PCP) and ketamine are dissociative anesthetics that are abused for their psychoactive effects, with ketamine having one-tenth the potency. PCP's popularity peaked during the 1970s. Ketamine gained popularity in the 1990s along with γ-hydroxybutyrate (GHB) and hallucinogenic amphetamines, which remain popular in nightclubs and "raves." Both xenobiotics affect the central nervous system (CNS), producing psychiatric and medical complications during an "out of body experience" and alteration in sensory perception. As a class of their own, they carry out these effects via inhibition of the N-methyl-D-aspartate (NMDA) receptor. The opioid, dextromethorphan, causes similar dissociative effects in high doses and has become popular among today's youth as it is easily obtained in cough suppressants. An understanding of the pharmacology and pathophysiology of PCP and ketamine is valuable in the diagnosis, management, and treatment of patients with toxicity from these agents.
PCP was discovered in 1926, but it was not developed as a general anesthetic until the 1950s. At the time, the Parke Davis drug company was searching for an ideal intravenous (IV) anesthetic that would rapidly achieve analgesia and anesthesia with minimal cardiovascular and respiratory depression.36 It was marketed under the name Sernyl because it rendered an apparent state of serenity when administered to laboratory monkeys. Its surgical use began in 1963, but PCP was rapidly discontinued when a 10% to 30% incidence of postoperative psychoses and dysphoria was documented over the subsequent 2-year period.81 By 1967 the use of PCP was limited exclusively to veterinary medicine as a tranquilizer marketed under the name Sernylan.
Simultaneously, in the 1960s, PCP was developing as a San Francisco street drug called "the PeaCe Pill."66 Numerous street names have been given to phencyclidine: on the West Coast it was called "angel dust," PCP, "crystal," "crystal joints" (CJs); Chicago called it "THC" or "TAC"; the East Coast opted for "the sheets," "Hog," or "elephant tranquilizer."121 Ironically, PCP was initially unpopular with drug users because of its dysphoric effects and unpredictable oral absorption.157 With time, however, its use spread in a similar geographic pattern to that of marijuana and lysergic acid diethylamide (LSD), from the coastal United States to the Midwest region.66
Phencyclidine abuse became widespread during the 1970s.25,182 The relatively easy and inexpensive synthesis coupled with the common masking of PCP as LSD, mescaline, psilocybin, cocaine, amphetamine, and/or "synthetic THC" (tetrahydrocannabinol) added to its allure and consumption.121 By the late 1970s PCP abuse had reached epidemicproportions.7 The Drug Abuse Warning Network (DAWN) reported that the number of PCP-related emergencies and deaths more than doubled in the 2 years from 1975 to 1977. In 1978 the National Institute of Drug Abuse reported that of young adults (18–25 years old), 13.9% had used PCP.50 The manufacture of phencyclidine was ultimately prohibited in 1978 when it was added to the list of federally controlled substances. Classifying ...