Brief Description:
Illegally manufactured in labs and sold as tablets, capsules, or colored powder.
It can be snorted, smoked, or eaten. Developed in the 1950s as an IV anesthetic,
PCP was never approved for human use because of problems during clinical
studies, including intensely negative psychological effects.
Street Names:
Angel dust, ozone, wack, rocket fuel, and many others.
Effects:
Many PCP users are brought to emergency rooms because of overdose or because of
the drug's unpleasant psychological effects. In a hospital or detention setting,
people high on PCP often become violent or suicidal.
Statistics and
Trends: In 2006, 187,000
Americans age 12 and older had abused PCP at least once in the year prior to
being surveyed. Source: National Survey on Drug Use and Health. The
NIDA-funded 2007 Monitoring the Future Study does not measure PCP use
among 8th and 10th graders but showed that 0.9% of 12th graders had abused PCP
at least once in the year prior to being surveyed. Source: Monitoring the
Future.
PCP
(phencyclidine) was developed in the 1950s as an intravenous anesthetic. Its use
has since been discontinued due to serious adverse effects.
How Is PCP (phencyclidine) Abused?
PCP
is a white crystalline powder that is readily soluble in water or alcohol. It
has a distinctive bitter chemical taste. PCP can be mixed easily with dyes and
is often sold on the illicit drug market in a variety of tablet, capsule, and
colored powder forms that are normally snorted, smoked, or orally ingested. For
smoking, PCP is often applied to a leafy material such as mint, parsley,
oregano, or marijuana. Depending upon how much and by what route PCP is taken,
its effects can last approximately 4–6 hours.
PCP (phencyclidine) Affects On The Brain
The use of PCP as an approved anesthetic in
humans was discontinued in 1965 because patients often became agitated,
delusional, and irrational while recovering from its anesthetic effects. PCP is
a “dissociative drug,” meaning that it distorts perceptions of sight and sound
and produces feelings of detachment (dissociation) from the environment and
self. First introduced as a street drug in the 1960s, PCP quickly gained a
reputation as a drug that could cause bad reactions and was not worth the risk.
However, some abusers continue to use PCP due to the feelings of strength,
power, and invulnerability as well as a numbing effect on the mind that PCP can
induce. Among the adverse psychological effects reported are:
·
Symptoms that
mimic schizophrenia, such as delusions, hallucinations, paranoia, disordered
thinking, and a sensation of distance from one’s environment.
·
Mood disturbances: Approximately
50 percent of individuals brought to emergency rooms because of PCP-induced
problems—related to use within the past 48 hours—report significant elevations
in anxiety symptoms.
·
People who have
abused PCP for long periods of time have reported memory loss, difficulties with
speech and thinking, depression, and weight loss. These symptoms can persist up
to one year after stopping PCP abuse.
·
Addiction: PCP
is addictive—its repeated abuse can lead to craving and compulsive
PCP-seeking behavior, despite severe adverse consequences.
Other Adverse Effects of PCP (phencyclidine) on Health
At low to
moderate doses, physiological effects of PCP include a slight increase in
breathing rate and a pronounced rise in blood pressure and pulse rate. Breathing
becomes shallow; flushing and profuse sweating, generalized numbness of the
extremities, and loss of muscular coordination may occur.
At high doses, blood pressure, pulse rate, and
respiration drop. This may be accompanied by nausea, vomiting, blurred vision,
flicking up and down of the eyes, drooling, loss of balance, and dizziness. PCP
abusers are often brought to emergency rooms because of overdose or because of
the drug’s severe untoward psychological effects. While intoxicated, PCP abusers
may become violent or suicidal and are therefore dangerous to themselves also
cause seizures, coma, and death (though death more often results from accidental
injury or suicide during PCP intoxication). Because PCP can also have sedative
effects, interactions with other central nervous system depressants, such as
alcohol and benzodiazepines, can also lead to coma.
What Treatment Options Exist?
Treatment for alkaloid hallucinogen (such as
psilocybin) intoxication—which is mostly symptomatic—is often sought as a result
of bad “trips,” during which a patient may, for example, hurt him- or herself.
Treatment is usually supportive: provision of a quiet room with little sensory
stimulation. Occasionally, benzodiazepines are used to control extreme agitation
or seizures.
There
is very little published data on treatment outcomes for PCP intoxication.
Doctors should consider that acute adverse reactions may be the result of drug
synergy with alcohol. Current research efforts to manage a life-threatening PCP
overdose are focused on a passive immunization approach through the development
of anti-PCP antibodies. There are no specific treatments for PCP abuse and
addiction, but inpatient and/or behavioral treatments can be helpful for
patients with a variety of addictions, including that to PCP.
How Widespread Is the Abuse of PCP (phencyclidine)?
Monitoring the Future Survey:
In 2008, 1.8 percent of high
school seniors reported lifetime use of PCP; past-year use was reported by 1.1
percent of seniors; and past-month use was reported by 0.6 percent. Data on PCP
use by 8th- and 10th-graders are not available.
National Survey on Drug Use and Health:
In 2007, 6.1 million persons aged 12 or older
reported that they had used PCP in their lifetime (2.5 percent), although only
137,000 persons in the same age group reported use in the past year—this
represents a decrease from 187,000 persons in 2006.
PCP (phencyclidine) Biochemistry and pharmacology
Biochemical action
The N-methyl-D-Aspartate (NMDA)
receptor, a type of ionotropic receptor, is found on the dendrites of neurons
and receives signals in the form of neurotransmitters. It is a major excitatory
receptor in the brain. Normal physiological function requires that the activated
receptor fluxes positive through the channel part of the receptor. PCP enters
the ion channel from the outside of the neuron and binds, reversibly, to a site
in the channel pore, blocking the flux of positive ions into the cell. PCP
therefore inhibits depolarization of neurons and interferes with cognitive and
other functions of the nervous system.
In a similar manner, PCP and
analogues also inhibit nicotinic acetylcholine receptor channels (nAChR). Some
analogues have greater potency at nAChR than at NMDAR. In some brain regions,
these effects act synergistically to inhibit excitatory activity.
PCP is retained in fatty tissue and
is broken down by the human metabolism into PCHP, PPC and PCAA.
The most troubling clinical effects
are likely produced by the indirect action of phencyclidine on the presynaptic
dopamine receptor (DA-2). This has been suggested to account for most of the
psychotic features. The relative immunity to pain is likely produced by indirect
interaction with the endogenous endorphin and enkephalin system in rats.
Structural analogs
More than 30 different analogues of
PCP were reported as being used on the street during the 1970s and 1980s, mainly
in the USA. The best known of these are PCPy (rolicyclidine,
1-(1-phenylcyclohexyl)pyrrolidine); PCE (eticyclidine,
N-ethyl-1-phenylcyclohexylamine); and TCP (tenocyclidine,
1-(1-(2-Thienyl)cyclohexyl)piperidine). These compounds were never widely-used
and did not seem to be as well-accepted by users as PCP itself, however they
were all added onto Schedule I of the Controlled Substance Act because of their
putative similar effects.
The generalized structural motif
required for PCP-like activity is derived from structure-activity relationship
studies of PCP analogues, and summarized below. All of these analogues would
have somewhat similar effects to PCP itself, although, with a range of potencies
and varying mixtures of anesthetic, dissociative and stimulant effects depending
on the particular substituents used. In some countries such as the USA,
Australia, and New Zealand, all of these compounds would be considered
controlled substance analogues of PCP, and are hence illegal drugs, even though
many of them have never been made or tested.
Brain effects
Like other NMDA receptor antagonists,
it is postulated that phencyclidine can cause a certain kind of brain damage
called Olney's lesions. Studies conducted on rats showed that high doses of the
NMDA receptor antagonist MK-801 caused irreversible vacuoles to form in certain
regions of the rats' brains, and experts say that it is possible that similar
brain damage can occur in humans. All studies of Olney's Lesions have only been
performed on animals and may not apply to humans. The research into the
relationship between rat brain metabolism and the creation of Olney's Lesions
has been discredited and may not apply to humans, as has been shown with
ketamine.
Phencyclidine has also been shown to
cause schizophrenia-like changes in the rat brain, which are detectable both in
living rats and upon necropsy examination of brain tissue. It also induces
symptoms in humans that are virtually indistinguishable from schizophrenia.
History and
medicinal use
PCP was first synthesized in 1926,
and later tested after World War II as a surgical anesthetic. Because of its
adverse side effects, such as hallucinations, mania, delirium, and
disorientation, it was shelved until the 1950s. In 1953, it was patented by
Parke-Davis and named Sernyl (referring to serenity), but was withdrawn
from the market two years later because of side-effects. It was renamed
Sernylan in 1967, and marketed as a veterinary anesthetic, but again
discontinued. Its side effects and long half-life in the human body made it
unsuitable for medical applications.
When smoked, some of it is broken
down by heat into 1-phenyl-1-cyclohexene (PC) and piperidine.
Recreational use
PCP comes in both powder and liquid
forms (PCP base is dissolved most often in ether), but typically it is sprayed
onto leafy material such as marijuana, mint, oregano, parsley, or ginger leaves,
then smoked.
PCP is a Schedule II substance in the
United States, a List II drug of the Opium Law in the Netherlands and a Class A
substance in the United Kingdom.
Method of
absorption
The term "embalming fluid" is often
used to refer to the liquid PCP in which a cigarette or joint is dipped, to be
ingested through smoking, commonly known as "boat" or "water." Smoking PCP is
known as "getting wet." A tobacco cigarette or cannabis joint dipped in PCP is
called by the street names "sherm stick," "sherm," "fry stick," "amp," "toe
tag", "dippa", "happy stick," and "wet stick." There is much confusion over the
practice of dipping cigarettes in "embalming fluid" leading some to think that
real embalming fluid may actually be used. Smoking actual formaldehyde will
cause intoxication, but may cause serious health consequences beyond those of
consuming PCP, due to the toxicity of formaldehyde and other embalming
chemicals. The slang term "embalming fluid" likely originated from PCP's somatic
"numbing" effect and the feeling of physical dissociation from the body. This is
one of the fastest growing means of using PCP, especially in the western United
States where its is sold for about $10 to $25 per joint or cigarette.
In its pure (base) form, PCP is a
yellow oil (usually dissolved in petroleum or diethyl ether or tetrahydrofuran).
Upon treatment with hydrogen chloride gas, or HCL saturated isopropyl alcohol,
this oil precipitates into white - tan crystals or powder (PCP hydrochloride) In
this form, PCP can be insufflated, depending upon the purity. However, most PCP
on the illicit market contains a number of contaminants as a result of makeshift
manufacturing, causing the color to range from tan to brown, and the consistency
to range from powder to a gummy mass. These contaminants can range from
unreacted piperidine and other precursors, to carcinogens like benzene and
cyanide - like compounds such as PCC (piperidinocyclohexyl carbonitrile).
Effects
Behavioural effects can vary by
dosage. Small doses produce a numbness in the extremities and intoxication,
characterized by staggering, unsteady gait, slurred speech, bloodshot eyes, and
loss of balance. Moderate doses (5-10 mg intranasal, or 0.01-0.02 mg/kg
intramuscular or intravenous) will produce analgesia and anesthesia. High doses
may lead to convulsions.
Psychological effects include severe
changes in body image, loss of ego boundaries, and depersonalization.
Hallucinations and euphoria are reported infrequently.
The drug has been known to alter mood
states in an unpredictable fashion, causing some individuals to become detached,
and others to become animated. Intoxicated individuals may act in an
unpredictable fashion, driven by their delusions and hallucinations.
Included in the portfolio of
behavioral disturbances are acts of self-injury including suicide, and attacks
on others or destruction of property. The analgesic properties of the drug can
cause users to feel less pain, and persist in violent or injurious acts as a
result. Recreational doses of the drug can also induce a psychotic state that
resembles schizophrenic episodes which can last for months at a time with toxic
doses. Users generally report an "out-of-body" experience where they feel
detached from reality, or one's consciousness seems somewhat disconnected from
consensus reality.
Symptoms are summarized by the
mnemonic device RED DANES: rage, erythema (redness of skin), dilated pupils,
delusions, amnesia, nystagmus (oscillation of the eyeball when moving
laterally), excitation, and skin dryness.
Horror stories
The American rapper Big Lurch
murdered an acquaintance and ate her lungs while on PCP. In The Man Who
Mistook His Wife for a Hat, a similarly gruesome murder is described. In
April 2009, a man in Bakersfield bit out his 4-year-old son's eye, and severely
damaged the other, before attempting to chop off his own legs with an axe while
under the influence of PCP.
In 1977, actor David Lochary died by
bleeding to death in his New York apartment after falling on a piece of glass
while on PCP.
Management of
intoxication
Management of phencyclidine
intoxication mostly consists of supportive care—controlling breathing,
circulation, and body temperature—and, in the early stages, treating psychiatric
symptoms. Benzodiazepines, such as lorazepam, are the drugs of choice to control
agitation and seizures (when present). Typical antipsychotics such as
phenothiazines and haloperidol have been used to control psychotic symptoms, but
may produce many undesirable side effects—such as dystonia—and their use is
therefore no longer preferred; phenothiazines are particularly risky, as they
may lower the seizure threshold, worsen hyperthermia, and boost the
anticholinergic effects of PCP. If an antipsychotic is given, intramuscular
haloperidol has been recommended.
Forced acid diuresis (with ammonium
chloride or, more safely, ascorbic acid) may increase clearance of PCP from the
body, and was somewhat controversially recommended in the past as a
decontamination measure. However, it is now known that only around 10% of a dose
of PCP is removed by the kidneys, which would make increased urinary clearance
of little consequence; furthermore, urinary acidification is dangerous, as it
may induce acidosis and worsen rhabdomyolysis (muscle breakdown), which is not
an unusual manifestation of PCP toxicity.
