PCP and Ketamine Toxicity

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Practice Essentials

Phenylcyclohexyl piperidine (PCP), also known as phencyclidine, was originally discovered in 1926; however, PCP was not introduced as a dissociative general anesthetic until the 1950s. Because of severe adverse effects, such as postoperative psychoses and dysphoria, its clinical use in humans was discontinued in 1965, although it remained widely used in veterinary medicine.

PCP was first introduced as a street drug in the late 1960s; despite gaining notoriety for unpleasant adverse effects, its use grew to epidemic proportions during the 1970s for its mind-altering properties. Many PCP users state that they have feelings of strength, power, and invulnerability while intoxicated with PCP. Some also report a numbing effect that may lead to anger, rage, selective amnesia of unpleasant memories, and acute psychoses. In 1978, PCP was transferred from Schedule III to Schedule II under the Federal Controlled Substance Act.

PCP is a potent N-methyl-D-aspartate (NMDA) receptor antagonist. Other NMDA receptor blockers that share similar chemical structures and possess varying degrees of adverse clinical effects are ketamine and MK-801 (dizocilpine), which is commonly used for research purposes. Ketamine is a tranquilizer, analgesic, and dissociative anesthetic commonly used for anesthesia induction (and off-label for procedural sedation/analgesia in children and for resistant depression), as well as in veterinary medicine.

Ketamine was developed by Parke-Davis in 1962 to replace PCP. It was initially introduced as a battlefield anesthetic for American soldiers during the Vietnam War and is still widely used in clinical practice. Its beneficial effect is the “dissociation” of brain stem functions from higher brain areas, which alters the sensation of pain and other stimuli during medical procedures, and produces amnesia regarding the event. In addition, patients receiving ketamine maintain spontaneous breathing and relatively stable cardiovascular functions.

Since 1965, the recreational use of ketamine has increased and it became very popular during the 1990s among young adults at dance clubs and raves in combination with other so-called “club drugs” (eg, gamma-hydroxybutyric acid, lysergic acid diethylamide [LSD], ecstasy). Because of its increased illicit use in the United States, ketamine was placed in Schedule III as a non-narcotic controlled substance in 1999.[1, 2]

Drug forms

Because PCP is inexpensive and relatively easy to manufacture, it is often misrepresented as other hallucinogenic substances, such as LSD, tetrahydrocannabinol (THC), mescaline, psilocybin, cocaine, and amphetamine. PCP is distributed in widely varying purities and forms (eg, powder, liquid, tablets, leaf mixtures, rock crystal) (see image below).[3]



View Image

Phenylcyclohexyl piperidine (PCP), also known as phencyclidine, in tablet form. Image courtesy of the US Drug Enforcement Administration.

Many drug users are unknowingly exposed to PCP because it is often used as an adulterant in marijuana, LSD, and methamphetamine to save on production costs of those other drugs. PCP can be taken in pill form, snorted as a powder, smoked, or injected intravenously or subcutaneously. In certain forms, PCP can inadvertently be absorbed through contact with the skin.

PCP that is sold on the street is known by names such as angel dust, ozone, wack, rocket fuel, dust, elephant tranquilizer, hog, ethyl-phenylcyclohexylamine (PCE), thienyl-cyclohexylpiperidine (TCP), porker, zoot, embalming fluid, love boat, crystal, horse tranquilizer, tic-tac, peace pill, sherms, purple rain, zombie, worm, live ones, little ones, and boat. When PCP is added to marijuana, the combination is sometimes sold as crystal super grass, killer joints, super weed, killer weed, krystal joint (KJ), and green leaves. When PCP is dusted on marijuana or mint leaves and soaked in embalming fluid, the combination is known as illy, wet, hydro, or fry. The various street names for PCP reflect its unpredictable and volatile effects.

Ketamine sold on the street is known by terms such as super acid, “K”, “special k,” vitamin K, cat Valium, cat tranquilizer, horse tranquilizer, ket, kit-kat, vetamine, K wire, KFC, keezy, kenny, ketanest, kenfitamine, ketaset, ketalar, kez, kitty, kustard, regretamine, wibble, forgetamine, triple K, and wonky.

Ketamine is odorless and tasteless and is available as a clear liquid, or a white/near-white crystalline powder. The liquid form is injected, mixed into drinks, or added to materials that can be smoked as with PCP. The powdered form is mostly snorted, compressed into pills, or used for intravenous or intramuscular injection when dissolved. Because of the induction of amnesia the drug has reportedly been used in sexual assaults referred to as “drug rape” or “date rape."[1]

Manufacture

Because PCP is relatively inexpensive to synthesize, it is an attractive drug for dealers. Its recipe can be found easily on the Internet, and it can be manufactured illegally in crude, underground laboratories. Most nonpharmaceutical PCP in the United States is manufactured in the Southern California area. Because of its continued use in veterinary medicine, pharmaceutical-grade formulations can be obtained through diversion.

Ketamine, unlike PCP, is relatively difficult to manufacture. For this reason, most illicit ketamine comes from diversion of pharmaceutical products destined for human or veterinary applications. According to reports from the US Drug Enforcement Administration (DEA), the major source of illegal ketamine in the United States is diverted from pharmacies in Mexico.

Pathophysiology

PCP is a 3-ringed molecule that is structurally similar to ketamine. However, PCP differs from ketamine in that it is longer acting, is more likely to cause seizures, and tends to cause more emergent confusion and delirium.

PCP is a noncompetitive antagonist at the glutamate NMDA receptor and binds to sites located in the cortex and limbic structures of the brain. This mechanism is believed to be responsible for most of the dissociative effects of PCP. PCP has been shown to effect biogenic amine (eg, dopamine, norepinephrine, serotonin) release and reuptake in a dose-dependent manner. These actions may account for the sympathomimetic effects after PCP ingestion. In addition, PCP may indirectly modulate cholinergic and GABAergic outflow in the CNS.

Ketamine’s molecular structure and mechanism of action are similar to those of PCP. It acts as a noncompetitive antagonist on the NMDA receptor. The drug's secondary interactions with muscarinic, nicotinic, and cholinergic receptors inhibit the neuronal uptake of norepinephrine, dopamine, and serotonin. At high doses, ketamine binds to mu and sigma opioid receptors, which are thought to be responsible for the loss of consciousness under controlled anesthesia.[2]

Pharmacokinetics

PCP is a weak base with a pKa of 8.6-9.4. In its nonionized or free base form, PCP is lipid soluble and easily diffuses across membranes. However, in an acidic environment, such as the stomach, PCP forms an ionized salt and becomes functionally trapped, preventing it from freely diffusing across the gastric mucosa. PCP that is absorbed from the alkaline duodenum can be secreted into the acidic stomach, creating a gastroenteric circulation. This phenomenon may explain the prolonged and wavering course of PCP intoxication.

PCP has a large volume of distribution (6.2 L/kg). Although the initial dose is distributed quickly in the brain, it is redistributed to other lipid-containing organs and can remobilize for hours, days, or possibly even weeks.[4] After entering the brain and reaching the acidic environment of the CSF, PCP becomes ionized. This ion trapping can produce levels of PCP in the CSF that are 6-9 times higher than those in plasma. PCP is predominantly metabolized in the liver to form glucuronide metabolites that are then excreted in the urine. A small amount of PCP is excreted unchanged in the urine.

Ketamine acts similarly to, but is less potent than PCP. The drug is highly bioavailable after intravenous or intramuscular injection with a volume of distribution of about 3-5 L/kg. Oral doses are less well absorbed and undergo extensive first-pass metabolism in the liver. The elimination phase lasts 45-60 minutes but can be as long as 4-6 hours in combination with other cerebral depressants. The half-life of ketamine is 10-15 minutes; however, 24-48 hours may be required before the user returns completely to baseline.

Similar to PCP, ketamine is redistributed from the CNS and undergoes hepatic transformation by the cytochrome P450 system into its active metabolite norketamine. Norketamine has about one third of the anesthetic potency of ketamine with a half-life of 2.5 hours. Ketamine metabolites are mainly excreted in the urine.[2]

Epidemiology

Epidemiologic data indicate that PCP abuse is not widespread and is not prevalent in adolescents. The National Institute on Drug Abuse (NIDA) Monitoring the Future Study, which included survey results from 1975-2006, revealed that the overall use of PCP by high-school seniors had decreased since 1979, when 7% of seniors used PCP.[5] PCP has retained the lowest lifetime prevalence and highest noncontinuation rates among high-school seniors compared with other hallucinogenic drugs (eg, LSD, ecstasy). 

A study of the prevalence of hallucinogen use from 2002-2019 reported a decline in PCP use during this timespan, overall [prevalence difference (PD) = −0.06, P < 0.001] and for adolescents (PD = −0.24, P < 0.001) and young adults (PD = −0.32, P < 0.0001).[6]

The 2022 Annual Report of the American Association of Poison Control Centers' National Poison Data System reported 116 single exposures of PCP, with 26 major outcomes and no deaths. In addition, 160 single exposures to ketamine with 9 major outcomes and 1 death were also reported. Of note, children and adolescents age 19 and younger accounted for 22 cases of PCP exposure and 27 cases of ketamine exposure.[7]

The Drug Abuse Warning Network (DAWN) estimated that the number of PCP-related ED visits rose more than fivefold from 2005 to 2011, increasing from 14,825 to 75,538. During that time, the largest increase in PCP-related ED visits was seen in patients 25 to 34 years old (from 5,556 to 34,329 visits). In 2011, 69% of patients making PCP-related ED visits were males, and 45% were 25 to 34 years old. Other illicit drugs, such as marijuana, cocaine, and heroin, were involved in 48% of PCP-related ED visits in 2011.[8]

The 2022 National Survey on Drug Use and Health (NSDUH) reported that 15,000 individuals 12-17 years old used PCP in the past 12 months. An additional 13,000 18-25 year olds and 177,000 adults 26 years old or older reported usage during the past year.[9]   

The use of ketamine among high-school seniors has declined in recent years. According to the NIDA, reported past-year use by 12th graders peaked in 2002, at 2.6%, then fell to 1.2% in 2022.[10] Ketamine use tends to be more frequent among high-school seniors of lower socioeconomic status.

From 1994-1999, ketamine-associated ED visits increased from 19 per year to 400 per year but have remained relatively unchanged since then. Approximately 80% of ketamine-related ED visits involved consumption of multiple drugs in addition to ketamine, mostly other “club drugs,” or in combination with alcohol, marijuana, cocaine, and heroine. Ketamine use was found to be highest among males younger than 26 years.[5]

The 2014 National Survey on Drug Use and Health comparison of 12-month ketamine use during 2006-2014 found that usage spiked in 2011 with 336,000 users then steadily declined, with 247,000 users in 2014. Male users outnumbered female users by approximately 2 to 1.[11]

Prognosis

The usual street dose of PCP is 1-6 mg and results in mild intoxication. Larger ingestions (6-10 mg) can cause toxic psychoses and signs of sympathetic hyperactivity, including hypertension, rigidity, hyperthermia, tachycardia, and seizure. Very large doses (≥ 200 mg) can result in death.

The major cause of death with PCP intoxication is behavioral disturbances that lead to self-destructive behaviors and impaired judgment. Injuries may be self-inflicted, result from exceptional physical exertion, or be sustained from resisting physical restraints. Deaths from the direct effects of PCP intoxication are related to hyperthermia, kidney failure, disseminated intravascular coagulation (DIC), and rhabdomyolysis. In a study of 1000 patients with PCP intoxication, rhabdomyolysis occurred in 25 patients and 10 patients developed acute kidney injury.[12, 13]

Despite reports of increased recreational use, only a few fatalities are attributed to ketamine poisoning alone or in combination with other drugs. Deaths related to ketamine abuse are mainly caused indirectly and related to falls, traffic injuries, drowning, and burns due to impaired perception, muscle weakness, and ataxia. However, death through choking on vomit has been reported.[14]

History

The dissociative effects of phenylcyclohexyl piperidine (PCP), also known as phencyclidine, cause patients to have disorganized thought processes, including delirium, amnesia, paranoia, and dysphoria. Therefore, obtaining a reliable history may not be possible. In addition, because PCP is frequently an adulterant, patients may not know that they have ingested PCP. The patient's friends and family should be questioned, if possible, to gain a greater understanding of the situation.

Physical Examination

Diagnosis of PCP intoxication is generally made clinically. PCP exposure is suggested by the patient's fluctuating behavior, nystagmus, motor disturbances, and autonomic stimulation.

The presentation of patients with PCP intoxication widely varies from inebriated and calm to agitated and, in some cases, extremely violent. An important diagnostic clue is nystagmus (lateral, horizontal, or rotatory). A large case series demonstrated nystagmus in 57% of patients with PCP intoxication, although smaller studies have found an incidence of 85% or higher.[15]  Many CNS depressants can produce nystagmus when taken in high doses; however, the patient is generally sedated when nystagmus is observed. In PCP exposure, the patient may have nystagmus when he or she is awake and agitated.

Additional autonomic effects at low doses (less than 5 mg) include the following:

Central and peripheral nervous system effects include generalized numbness of extremities, and loss of muscular coordination; mental status can vary from stimulation and euphoria to depression and coma, which occurs in a dose-related manner. At high doses (10 mg or more) blood pressure, heart rate and respirations may fall. This is often accompanied by nausea, vomiting, blurred vision, drooling, ataxia, and dizziness.

Patients may demonstrate bizarre posturing or facial expressions. Motor disturbances include the following dystonic reactions:

Psychobehavioral features of PCP intoxication often mimic symptoms of schizophrenia and can include delusions, hallucinations, acute anxiety, paranoia, disorganized thinking, violence, and a sensation of distance from one’s environment.[16]  Elevation of anxious symptoms is frequently experienced. Long-term abuse of PCP may produce memory loss, speech difficulties, depression, and weight loss. Addiction to and withdrawal from PCP can occur after chronic use and manifest as craving and compulsive PCP-seeking behavior.[17]

During acute presentations in the emergency department, PCP abusers may become violent or suicidal and should be seen as a danger to themselves and/or others. High doses of PCP can cause seizures, coma, hyperthermia and death (frequently related to unintentional injury or suicide while intoxicated). Coma is often related to substances such as alcohol or benzodiazepines that can enhance the sedative effects of PCP.[18]

The evaluation of PCP-intoxicated patients with actual or suspected trauma may be challenging because of the dissociative anesthetic effects that can mask signs and symptoms (eg, abdominal pain or those associated with hidden injuries). Like ketamine, PCP is thought to prevent the integration of sensory input to create meaningful responses. Because of the analgesic effects of PCP and lack of normal pain response, PCP-intoxicated patients have sometimes been described as having extraordinary strength. PCP-intoxicated patients have broken handcuffs and fractured bones in the process.

Children may inhale PCP fumes in their environments, or they may ingest or have topical exposure to PCP in their surroundings. Most parents who accompany their children for treatment of PCP exposure deny the possibility of their child's drug intoxication. Children exposed to PCP typically have symptoms similar to those of adults and can exhibit diminished response to tactile and verbal stimuli, bizarre behavior, ataxia, nystagmus, expressionless stare, dystonic posturing, irritability, poor feeding, seizures, and possibly miosis and hypertension.[19]

Incidences of hallmark findings in 1000 patients with PCP intoxication are as follows:[12]

Incidences of sensorium findings in 1000 patients with PCP intoxication are as follows:

Incidences of behavioral findings in 1000 patients with PCP intoxication are as follows:

Incidences of motor findings in 1000 patients with PCP intoxication are as follows:

Incidences of cholinergic findings in 1000 patients with PCP intoxication are as follows:

Incidences of anticholinergic findings in 1000 patients with PCP intoxication are as follows:

Incidences of abnormal vital signs in 1000 patients with PCP intoxication are as follows:

Ketamine

Ketamine produces physical effects similar to PCP; however, symptoms are often of shorter duration. The hallmark of ketamine is its dissociative effect. Ketamine-provoked sensations are dose-related and range from a pleasant feeling of floating in a colorful “wonder world” (“K-land”) to the terrifying feeling of complete sensory detachment similar to a near-death or out-of-body experiences (“K-hole”).[20]

Other symptoms that can occur with ketamine intoxication include the following:[1]

Impaired verbal information processing, cystitis, and cholangiopathy are associated with chronic exposure to ketamine.[21, 22]

Laboratory Studies

In general, the routine laboratory workup in patients who present with toxicity involving phenylcyclohexyl piperidine (PCP), also known as phencyclidine, should focus on the following:

Quantitative laboratory analysis is generally not very helpful because serum and urine levels do not reflect the drug's vast lipid storage, nor does the precise serum concentration correlate with the clinical effect. Results of toxicologic urine screening may remain positive for several weeks because of PCP's large volume of distribution.

Qualitative plasma or urine levels may help establishing the diagnosis but should be interpreted with care. Urine screening for PCP should be part of the diagnostic workup in children and infants presenting with acute dystonic reactions.[23]

Ketamine levels, as well as norketamine levels, can be determined in urine; however, these specific tests are generally not readily available and are not clinically useful. PCP may cross-react with ketamine assays.

Diphenhydramine and dextromethorphan (which are also frequently abused N-methyl-D-aspartate [NMDA] receptor antagonists) can produce false-positive urine drug screens for PCP because of their similar chemical structures.

Other useful tests to determine the presence of rhabdomyolysis, kidney dysfunction, and hypoglycemia include measurements of electrolytes, glucose, blood urea nitrogen (BUN), creatinine, and total creatine kinase levels, as well as a urinalysis (for myoglobin). An arterial blood gas (ABG measurement may be indicated to assess for metabolic acidosis and hypoxemia. A urine pregnancy test is indicated in female patients of childbearing age.

Medical Care

Medical management of intoxication with phenylcyclohexyl piperidine (PCP), also known as phencyclidine, is primarily supportive and encompasses treatment of agitated behavior, seizures, and hyperthermia. Therefore, close monitoring of vital signs including temperature is required. If delirium is severe and compromises patient or staff safety, deep sedation with endotracheal intubation may be necessary.

The American Academy of Child and Adolescent Psychiatry (AACAP) has established a practice parameter guideline for the assessment and treatment of children and adolescents with substance use disorders.[24]

Patients with recent oral use of PCP are candidates for GI decontamination. Activated charcoal (1 g/kg) may be administered and repeated every 4 hours for several doses in most symptomatic patients. Activated charcoal adsorbs PCP and increases its nonrenal clearance.[25] Because mental status can abruptly change, ipecac syrup and GI lavage are not recommended for GI decontamination.

Because PCP is a weak base, treatment in the past included acidification of the patient's urine to increase the drug's urinary excretion. This therapy is no longer recommended because severely intoxicated patients are at risk for acidosis and rhabdomyolysis and because the acidification of urine promotes the precipitation of myoglobin within the renal parenchyma. Furthermore, urinary acidification has never been proven to decrease morbidity or mortality. Because of its large volume of distribution, PCP is not effectively removed with hemodialysis or hemoperfusion.

Patients intoxicated with PCP have been known to demonstrate violent behavior, and they can often present a danger to the clinical staff. The most important approach to management of agitated behavior is the implementation of safe physical restraints and chemical sedation. Benzodiazepines are usually effective in managing aggressive behavior.

Anxiety and agitation can be managed by decreasing external stimuli such as noise, light, and touch. Benzodiazepines are the first means in anxiety treatment, and large doses may be required in severely agitated patients. Benzodiazepines also reduce the occurrence of vivid dreams.

Phenothiazines and butyrophenones should be avoided because they may cause significant hypotension, worsen hyperthermia, exacerbate any anticholinergic effect, may induce dysrhythmias, lower the seizure threshold, and cause dystonic reactions. Acute dystonic reactions can be controlled with diphenhydramine.

Seizure activity is seen in approximately 3% of patients presenting with PCP intoxication. Seizures should be treated with benzodiazepines, followed by barbiturates, propofol, or both.

In some patients severe hypertension with end-organ effects may persist even after the use of benzodiazepines. Phentolamine or nitroprusside are the agents of choice in such cases to achieve adequate blood pressure control.

Management of hyperthermia should include aggressive mechanical cooling. In profoundly hyperthermic (> 40.5°C) patients, rapid sequence induction with endotracheal intubation and paralysis should be considered if no response to more conservative measures is noted.

Rhabdomyolysis requires adequate hydration with normal saline in order to maintain a urine output of 2-3 mL/kg/h, as well as close monitoring of creatine phosphokinase (CPK) levels.

Admit the patient who has ingested PCP to an ICU if evidence of hyperthermia, seizure activity, or rhabdomyolysis is present.

Treatment of acute ketamine toxicity is predominantly supportive. As with PCP, benzodiazepines are the initial treatment to reduce agitation and excess neuromuscular activity.[21]   

The chronic effects of ketamine toxicity are usually reversible, with cessation of ketamine use. Cystitis requires a multidisciplinary stepwise approach of pharmacotherapy (eg, oral analgesics or anticholinergics, intravesical hyaluronic acid instillation or botulinum toxin A injection) and surgery (eg, hydrodistension, bladder reconstruction).[26, 27] Cholangiopathy is managed with pain medications and biliary stenting to alleviate obstructions, if needed.[21]

Consultations

A medical toxicologist or the staff at a regional poison control center may provide additional information about PCP intoxication and about current patient care recommendations.

Long-Term Monitoring

Refer the patient for drug rehabilitation.

Because of its long-lasting side effect of inducing or unmasking psychopathologic symptoms, continued outpatient therapy including prolonged use of tranquilizers may be necessary for patients after PCP intoxication.[28]

Medication Summary

No proven antidotes for phenylcyclohexyl piperidine (PCP), also known as phencyclidine, toxicity are known. Pharmacologic therapy facilitates supportive care and seizure control, with special attention to respiratory and cardiac function.

Diazepam (Valium)

Clinical Context:  Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA. Although seizures may be promptly controlled, seizure activity resumes in a significant proportion of patients, presumably because of the short duration of action with an initial dose of IV diazepam. Rapidly distributes to other body fat stores. Twenty minutes after initial IV infusion, serum concentration drops to 20% of Cmax.

Lorazepam (Ativan)

Clinical Context:  By increasing the action of GABA, (major inhibitory neurotransmitter in the brain), may depress all levels of CNS, including limbic and reticular formation

Pentobarbital (Nembutal)

Clinical Context:  Short-acting barbiturate with sedative, hypnotic, and anticonvulsant properties; can produce all levels of CNS mood alteration.

Propofol (Diprivan)

Clinical Context:  Phenolic compound that is a sedative hypnotic agent used for induction and maintenance of anesthesia or sedation. Has also been shown to have anticonvulsant properties.

Class Summary

Benzodiazepines are first-line agents for controlling seizures in patients with PCP toxicity. Barbiturates, propofol, or both provide a useful adjunct in the treatment of seizures or treatment of status epilepticus unresponsive to benzodiazepines. All of these agents are helpful in sedating patients with extreme agitation.

Activated charcoal (Actidose-Aqua, Liqui-Char)

Clinical Context:  Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water.

Class Summary

Consider activated charcoal decontamination in patients with oral PCP overdose who present within 4 hours of ingestion.

Diphenhydramine (Benadryl)

Clinical Context:  First-generation antihistamine with anticholinergic effects that binds to H1 receptors in the CNS and the body.

Competitively blocks histamine from binding to H1 receptors. Has significant antimuscarinic activity and penetrates CNS, which causes pronounced tendency to induce sedation. Approximately half of those treated with conventional doses experience some degree of somnolence. A small percentage of children paradoxically respond to diphenhydramine with agitation.

DOC for initial treatment of acute dystonia or akathisia not caused by antihistamines. Use diazepam for treatment of acute dystonia secondary to antihistamines.

Class Summary

These are used for treatment for acute ketamine-induced dystonia.

Nitroprusside (Nitropress)

Clinical Context:  Produces vasodilation and increases inotropic activity of the heart. At higher dosages it may exacerbate myocardial ischemia by increasing the heart rate.

Phentolamine (OraVerse, Regitine)

Clinical Context:  Alpha-1 and alpha-2 adrenergic blocking agent that blocks circulating epinephrine and norepinephrine action, reducing hypertension that results from catecholamine effects on the alpha receptors.

Class Summary

Recommended treatment agents for PCP-induced malignant hypertension with end-organ damage, if blood pressure control continues to be inadequate after agitation treatment.

Author

Stephan Brenner, MD, MPH, Resident Physician, Department of Emergency Medicine, Washington University in St Louis School of Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

William H Dribben, MD, Assistant Professor, Division of Emergency Medicine, Washington University in St Louis School of Medicine

Disclosure: Nothing to disclose.

Specialty Editors

Mary L Windle, PharmD, Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Jeffrey R Tucker, MD, Assistant Professor, Department of Pediatrics, Division of Emergency Medicine, University of Connecticut School of Medicine, Connecticut Children's Medical Center

Disclosure: Received salary from Merck for employment.

Chief Editor

Stephen L Thornton, MD, Associate Clinical Professor, Department of Emergency Medicine (Medical Toxicology), University of Kansas Hospital; Medical Director, University of Kansas Hospital Poison Control Center; Staff Medical Toxicologist, Children’s Mercy Hospital

Disclosure: Nothing to disclose.

Additional Contributors

Halim Hennes, MD, MS, Division Director, Pediatric Emergency Medicine, University of Texas Southwestern Medical Center at Dallas, Southwestern Medical School; Director of Emergency Services, Children's Medical Center

Disclosure: Nothing to disclose.

Timothy E Corden, MD, Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Ryan J Petersen, MD, to the original writing and development of this article.

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Phenylcyclohexyl piperidine (PCP), also known as phencyclidine, in tablet form. Image courtesy of the US Drug Enforcement Administration.

Phenylcyclohexyl piperidine (PCP), also known as phencyclidine, in tablet form. Image courtesy of the US Drug Enforcement Administration.