General information

Phencyclidine or 1-(1-phenylcyclohexy-1) piperidine (known as PCP, “angel dust”, and many other names) was originally developed as an anesthetic, but was abused as an illicit drug from the late 1960s onwards. It is a dopamine receptor agonist and an antagonist at the N-methyl- d -aspartate (NMDA) subtype of glutamate receptors. It has anticholinergic properties through blockade of ion channels in acetylcholine receptors. It has been used in some countries as an anti-parkinsonian agent [ ].

The psychoactive effects of phencyclidine are stimulant and similar to the effects of hallucinogens. The hallucinations it can cause are often bizarre, frightening, and challenging. Aggressive behavior, usually with amnesia, is common. Self-destructive 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 [ ].

Although the effects of phencyclidine are usually short-lived, it can cause prolonged and severe behavioral disturbances, exaggeration of pre-existing thoughts, and serious medical complications [ ].

Drug studies

Observational studies

Among 107 consecutive patients with phencyclidine intoxication, the diagnosis was confirmed by positive urine assay in 27 [ ]. 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 [ ]. 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 [ ]. The effects that they reported are listed in Table 1 , the self-reported unwanted behaviors in Table 2 , and the withdrawal effects in Table 3 .

Table 1
Self-reported effects of phencyclidine in 68 users
Effect % Effect %
Reduced appetite 62 Increased sex drive 29
Confused thoughts 60 Visual hallucinations 28
Loss of memory 59 Paranoia 27
Increased strength 57 Ringing in ears 24
Feeling “speedy” 56 Headaches 22
Euphoria 54 Reduced sex drive 21
Drowsiness 52 Fatigue 21
Bad trips 44 Auditory hallucinations 21
Insomnia 41 Feeling hot 19
Depression 35 Reduced strength 18
Dizziness 34 Vomiting 13
Increased anger 34 Feeling of detachment 13
Increased anxiety 34 Increased appetite 7.4
Increased violence 32 Reduced anxiety 7.4

Table 2
Self-reported unwanted behaviors in 68 users of phencyclidine
Behavior % Behavior %
Lost money 48.5 Hurt someone else 23.5
Got lost 39.7 Unwanted sexual encounter 19.1
Took drugs 35.3 Attempted suicide 13.2
Got into fight 30.9 Committed crime 11.8
Hurt yourself 26.5 Had car accident 10.3

Table 3
Self-reported symptoms after withdrawal of chronic phencyclidine in 68 users
Symptom % Symptom %
Craving for PCP 52 Headache 16
Increased need for sleep 49 Insomnia 15
Poor memory 46 None 15
Depression 44 Recurring tastes 13
Laziness 44 Panic 12
Increased appetite 38 Reduced appetite 8.8
Confused thoughts 35 Reduced need for sleep 4.4
Flashbacks 32 Feeling “speedy” 1.5
Irritable 31 Feeling hot 1.5
Feeling weak 31 Ringing in ears 1.5
Increased anxiety 22

Organs and systems

Cardiovascular

In seven cases of poisoning with phencyclidine, death followed a hypertensive crisis [ ]. In one case an acute episode of hypertension resulted in coma and blindness [ ].

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