ARYLCYCLOHEXYLAMINES: PCP AND KETAMINE

Phencyclidine (PCP) was developed for analgesics and anaesthetics, but it is now obsolete because of postoperative psychoses. It is still used in veterinary science. It causes sedation, immobility, amnesia and analgesia. The name 'dissociative anaesthesia' is used in this connection.

As an anaesthetic it has been replaced by ketamine (brand name Ketalar) (note 150). This is not a patented product. Ketamine is also manufactured in Hungary and Yugoslavia. PCP and ketamine affect the cortex and the limbic system. Application rapidly brings on analgesia and amnesia. Lack of consciousness lasts 10 to 15 minutes after intravenous application, analgesia lasts 40 minutes, and amnesia can last 1 to 2 hours. Coming round again can take hours, and is sometimes accompanied by unpleasant dreams and hallucinations. Almost 50~ of the persons above 30 experience excitation/delirium or are bothered by visual hallucinations. This is much less common among children and young adults, which is why it is mainly used in child surgery.

Intracerebral pressure, intraocular pressure and cerebral circulation increase. The pharyngeal and laryngeal reflexes remain intact. The coughing reflex is repressed, bronchial resistance is reduced, bronchial spasms are suspended.

There is little relaxation of the muscles, and muscular tension may increase, sometimes accompanied by purposeless movements. Metabolism increases. It has many sideeffects: bizarre and violent behavior, hallucinations, agitation, catatonic rigidity, disorientation, lack of coordination, nystagmus, hypersalivation, vomiting, convulsions, numbness, hypertension, tachycardia, cardiovascular depression is rare. Malign hyperpyrexia with rhabdomolysis resulting in collapse of the kidneys can occur.

The treatment of all toxic symptoms is symptomatic. The toxic psychosis is indistinguishable from schizophrenia. Haloperidol is preferable to chlorpromazine. Acid urine increases the secretion.

There are many contraindications: glaucoma, hypertension, cerebrovascular accident in the case history, heart weakness, increased intracranial pressure, psychiatric deviations, esp. schizophrenia.

It affects the NMDA receptor and inhibits the reuptake of dopamine, serotonin and noradrenaline. Selfinjection behavior occurs among monkeys with PCP.

PCP appeared as a street drug in the Sixties under a variety of names: angel dust, angel hair, angel mist, crystal, cyclone, horse tranquillizer, dust, killer weed, scuffle, peace weed, peace pills (notes 151, 152, 153, 154). It has never become popular in Europe.

Ketamine is also sometimes to be found on the drug market, where it is sold as XTC (Rotterdam and environs, February/March 1992). This is also reported from England (note 155).