Phencyclidine delirium

Other hallucinogenic drugs including substances related to LSD are mentioned under delirium. Phencyclidine and ketamine can also produce similar hallucinatory states without delirium including time distortion, distortion of body image, synaesthesia, visual hallucinations, depersonalisation, derealisation, paranoid ideation and a schizophreniform psychosis which includes the negative symptoms of schizophrenia (Gorelick Balster, 1995). 

Glassification of Substance-Related Disorders. The DSM-IV classification system (1) divides substance-related disorders into two categories (/) substance use disorders, ie, abuse and dependence and (2) substance-induced disorders, intoxication, withdrawal, delirium, persisting dementia, persisting amnestic disorder, psychotic disorder, mood disorder, anxiety disorder, sexual dysfunction, and sleep disorder. The different classes of substances addressed herein are alcohol, amphetamines, caffeine, caimabis, cocaine, hallucinogens, inhalants, nicotine, opioids, phencyclidine, sedatives, hypnotics or anxiolytics, polysubstance, and others. On the basis of their significant socioeconomic impact, alcohol, nicotine, cocaine, and opioids have been selected for discussion herein. 

Phencyclidine (l-[l-phenylcyclohexyl] piperidine, PCP) was originally developed as an intravenous anesthetic in the 1950s. Used for this indication, it causes a trance-like state without loss of consciousness and was hence classified as a dissociative anesthetic. However, it was soon withdrawn from human use because it produced unpleasant hallucinations, agitation, and delirium. The product was later used in veterinary medicine. Ketamine, a chemically closely related substance, was developed to replace PCP and is stiU in use as a dissociative anesthetic in children. Ketamine is less potent than PCP, and its effects are of shorter duration. However, it may also cause hallucinations (see the section on ketamine in Chapter 7, Club Drugs ). Much of the ketamine sold on the street (special K, cat Valium) has been diverted from veterinarians offices. 

Phencyclidine (PCP) abuse remains a serious public health problem in large urban areas of the United States, with recent trends suggesting increased use after a period of decline (Crider, this volume). Most clinical and research attention has focused on the psychiatric and medical manifestations of acute or subacute PCP intoxication, especially the organic mental disorders (toxic delirium, psychosis, or depression) that PCP can induce (McCarron et al. 1981 McCarron, this volume Sioris and Krenzelok 1978). 

Acute phencyclidine intoxication can proceed through stages from stupor to coma with unresponsiveness to pain. Delirium lasting several days is common during recovery from coma and may occur transiently as the final phase of an episode of intoxication (Gorelick Balster, 1995). Ketamine has similar effects when abused recreationally. When used as an anaesthetic in adults, it... 

The mechanisms of action of phencyclidine and ketamine are complex (Gorelick Balster, 1995). The drugs are non-competitive antagonists at NMDA receptors, and also bind to associated phencyclidine/sigma opioid receptors. They also have agonist actions at dopamine receptors, complex interactions with both nicotinic and muscarinic acetylcholine receptors and poorly understood interactions with noradrenergic and serotonergic systems. These multiple actions may combine to produce delirium and psychotic reactions. 

Phencyclidine, PCP, or l-(l-phenylcyclohexyl) piperidine, is an arylcyclohexamine with structural similarities to ketamine. It is a lipophilic weak base with a pKa of 8.5. Phencyclidine was originally synthesized and marketed under the trade name Semyl by Parke-Davis for use as an intravenously administered anesthetic agent in humans. Distribution began in 1963 but was discontinued in 1965 due to a high incidence (10 to 20%) of post-operative delirium and psychoses. However, its use continued as a veterinary tranquilizer for large animals until 1978, when all manufacture was prohibited and PCP was placed in Schedule II of the federal Controlled Substances Act (1970). 

Phencyclidine (PCP) was developed in late 1950 as an intravenous anesthetic agent. PCP produces anesthesia and analgesia with respiratory or cardiovascular depression. However, postoperatively, the drug produced psychotomimetic effects (e.g., delirium and hallucinations) and was subsequently withdrawn from the market. 

Ketamine is a phencyclidine derivative and as such has abuse potential. Phencyclidine was developed in the 1950s as an anaesthetic, but its use was abandoned because it caused hallucinations and delirium. It became popular as PCP (phenylcyclohexylpiperidine), a drug of abuse, in the 1970s. 

Ketamine is a potent analgesic-anesthetic that is also effective intramuscularly. One particular property, production of cardiovascular stimulation, is of special advantage in elderly patients and those in shock (e.g., from bums). However, its propensity to precipitate hallucinations, delirium, disorientation, and other perceptual illusions postoperatively in about 12% of patients has led to its infrequent use in the United States. Ketamine s close structural analogy to the notorious and dangerous hallucinogen, phencyclidine (PCP, angel dust ), should be noted. This drug, which was first also introduced as an... 

Ketamine can cause attention deficits and memory problems. At higher doses, users may experience symptoms similar to those seen with phencyclidine (PCP) use, such as hallucinations, dream-like states, or delirium. Even higher doses of Ketamine may cause high blood pressure, depression, and severe breathing problems, which may lead to death. 

PHENCYCLIDINE (PCP) was introduced in the 1950s as a nonbarbiturate anesthetic, but was removed from the mark in 1978 because of urxfesirable side effects (e.g., delirium, agitation, hallucinations). 

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