Phencyclidine

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). 

Illicit use of PCP as a hallucinogenic agent was first reported in San Francisco in 1967.1 It was first abused in oral form but then gained popularity in the smoked form as this mode of drug 

Phencyclidine is typically self-administered by the oral, intravenous, or smoked routes. After oral administration to healthy human volunteers, the bioavailability was found to vary between 50 and 90%.4 In this study, peak plasma concentrations were achieved after 1.5 h and appeared to correlate with the time to reach maximum pharmacological effects. However, because there have been no comprehensive clinical controlled studies of phencyclidine, a correlation between PCP blood concentrations and pharmacological effects has not been definitively documented. Maximum serum PCP concentrations ranged between 2.7 and 2.9 ng/ml after 1 mg PCP administered orally.4 

Wall et al.9 administered 1.3 pg/kg of 3H-PCP intravenously to human volunteers and collected blood samples for 72 h. Data from this study suggested a two-compartment pharmacokinetic model with a plasma half-life for PCP of 7 to 16 h. Domino et al.10 further analyzed the data from Wall et al. and developed a more complex three-compartment PK model. The reported half-lives for 

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postoperatively, the drug produced psychotomimetic effects (e.g., delirium and hallucinations) and was subsequently withdrawn from the market. 

PCP at low dose (50 p.g/kg) produces emotional withdrawal, concrete thinking, and bizarre responses to projective testing. With high doses of PCP, abusers exhibit hostile and aggressive behavior. 

PCP has been a street drug in the United States since the 1960s, called angel dust, ozone, wack, killer, and joints. Initially, it was not popular because of its variant absorption and devastating dysphoric effects. The drug is easily and cheaply synthesized with (piperdines and cyclohexane). Many PCP derivatives have been used as street drugs. 

PCP typically causes tachycardia and hypertension. PCP is sold in the form of capsules, tablets, powder, as a solution in water or alcohol, or as rock salt. It may be sniffed, smoked, or injected through intravenous or subcutaneous injection. 

PCP intoxication typically produces miosis, nystagmus, hypertension, tachycardia, salivation, flushing, sweating, ataxia, and CNS stimulation or depression. Overdose of PCP is dangerous, as the user becomes violent and emergency treatment is required. It is necessary to keep the user calm and not leave him alone. Withdrawal symptoms of PCP are tremor, seizures, diarrhea, piloerection, and vocalizations. 

The psychoactive effects of phencyclidine are stimulant and similar to the effects of hallucinogens. Hallucinations are often bizarre, frightening, and challenging. Aggressive behavior, usually with amnesia, is common. Self-destruc-tive actions are also seen. Overdosage is associated with paresthesia, slurred speech, ataxia, and later catatonia, dilated pupils, and coma, with tachycardia, hypertension, and dysrhythmias. Seizures and deaths have occurred (SED-11, 86 4). 

Although the effects of phencyclidine are usually shortlived, it can cause prolonged and severe behavioral disturbances, exaggeration of pre-existing thoughts, and serious medical complications (5). 

Among 107 consecutive patients with phencyclidine intoxication, the diagnosis was confirmed by positive urine assay in 27 (6). The most common abnormalities were mental/behavioral (89%) and nystagmus (85%). There were also increases in blood pressure, temperature, and heart rate. The most common serious medical complication requiring hospitalization was rhabdomyolysis, which occurred in three patients, two of whom developed acute renal insufficiency. 

Four major and five minor clinical patterns of acute phencyclidine intoxication have been described in 1000 patients (7). Major patterns were acute brain syndrome (24.8%), toxic psychosis (16.6%), catatonic syndrome (11.7%), and coma (10.6%). Minor patterns included lethargy or stupor (3.8%) and combinations of bizarre behavior, violence, agitation, and euphoria in patients who were alert and oriented (32.5%). Patients with major patterns of toxicity usually required hospitalization and had most of the complications. Patients with minor patterns generally had mild intoxication and did not require hospitalization, except for treatment of injuries or autonomic effects of phencyclidine. There were various types of injuries in 16%, and aspiration pneumonia in 1.0%. There were 22 cases of rhabdomyolysis (2.2%), and three patients required dialysis for renal insufficiency. One patient who had been comatose died suddenly with a pulmonary embolism. 

Of 68 users of phencyclidine (37 men, 31 women aged 14-38 years), 42 used it daily, and 14 used it intravenously 25 considered themselves to be addicted to it (8). The effects that they reported are listed in Table 1, the withdrawal effects in Table 2, and the unwanted behaviors in Table 3. 

PCP also increases calcium-independent [3H]DA release from dissociated rat mesencephalon cell cultures122 and striatal synaptosomes.123 PCP has been found to be a potent inhibitor of [3H]DA uptake in rat striatum,124 127 to competitively inhibit binding of [3H]BTCP, a PCP derivative and 

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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. 

X-ray structure, 3, 158-159 Phenazin-l(2H)-one, 3,4-dihydro-synthesis, 2, 69 Phenazopyridine, 1, 145 as urinary tract analgesic, 2, 517 Phenbenzamine as antihistamine, 1, 177 Phencyclidine... 

Dissociative anesthetic is a term applied to phencyclidine and ketamine which induce a peculiar subjective state of dissociation from the environment, together with sedation, immobility, amnesia, analgesia, and ultimately coma. 

Psychotomimetic Drugs. Figure 2 Chemical structures of the dissociative anesthetics phencyclidine (PCP) and ketamine. Both are arylcycloalkylamine derivatives that are open channel blockers of the NMDA channel. 

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. 

Garden City, NY, Medical Examination Publishing, 1981 Snyder SH, Faillace L 2,3-Dimethoxy-4-methyl-amphetamine (STP) a new hallucinogenic drug. Science 1388 669-670, 1967 Spielewoy C, Markou A Withdrawal from chronic phencyclidine treatment induces long-lasting depression in brain reward function. Neuropsychopharmacology 28 1106-1116,2003... 

Ketamine is a cyclohexane human and veterinary injectable anesthetic that is also known by the slang names K, special K, vitamin K, and cat Valium (Bobo and Miller 2002). It is produced in a liquid form or as a white powder and is usually ingested orally or intranasally but is occasionally administered intramuscularly. Ketamine is a phencyclidine (PCP) analog that was first developed in 1962. 

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