Ketamine hallucinations

Another injectable anesthetic widely used in feline and primate practice is ketamine hydrochloride [1867-66-9]. Ketamine, a derivative of phencychdine, can be chemically classified as a cyclohexamine and pharmacologically as a dissociative agent. Analgesia is produced along with a state that resembles anesthesia but in humans has been associated with hallucinations and confusion. For these reasons, ketamine is often combined with a tranquilizer. The product is safe when used in accordance with label directions, but the recovery period may be as long as 12—24 h. 

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 However, it was soon withdrawn from human use because it produced unpleasant hallucinations, agitation, and delirium.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. 

Fadda F, Columbo G, Mosca E, et al Suppression by gamma-hydroxybutyric acid of ethanol withdrawal syndrome in rats. Alcohol Alcohol 24 447-451, 1989 Fine J, Finestone SC. Sensory disturbances following ketamine anesthesia recurrent hallucinations. Anesth Analg 52 428 30, 1973 Freese TE, Miotto K, Reback CJ The effects and consequences of selected club drugs. J Subst Abuse Treat 23 151—156, 2002... 

Controlled clinical investigations with careful titration of doses in normal subjects demonstrate that ketamine produces negative symptoms, such as withdrawal and the subtle cognitive impairments associated with schizophrenia [25]. As is the case for schizophrenia, these symptoms occur without clouding of consciousness or frank dementia. Positive symptoms with auditory hallucinations and fully... 

Ketamine (special K, jet, green), chemically related to PCP, is a veterinary anesthetic that can cause hallucinations, delirium, and vivid dreams. 

Figure 6.2 The chemical structure of ketamine (top) is related to the psychedelic PCP (bottom). Both chemicals produce strong hallucinations and psychedelic effects. However, while the effects of ketamine may only last an hour, the effects of PCP can last several hours after the drug is taken.

Memantine (Namenda) [Anti Alzheimer Agent/NMDA Receptor Antagonist] Uses Mod/ evere Alzheimer Dz Action N-methyl-D-aspartate recqjtor antagonist Dose Target 20 mg/d, start 5 mg/d, t 5 mg/d to 20 mg/d, wait >1 wk before t dose use doses if >5mg/d Caution [B, /-] Hqjatic/mild-mod renal impair Disp Tabs, sol SE Dizziness Interactions t Effects W amantadine, carbonic anhydrase inhibitors, dextromethorphan, ketamine, Na bicarbonate t effects W/ any drug, herb, food that alkalinizes urine EMS Use NaHCOs w/ caution OD May cause restlessness, hallucinations, drowsiness, and fainting symptomatic and supportive... 

Ketamine, a general anesthetic producing hallucinations and exhibiting an addiction potential, and norketamine have been determined in urine using SPE combined with RPLC-ESI(+)-MS-MS [49]. Cheng and Mok [49] developed a fast HPLC-MS-MS method able to separate and detect ketamine in a 2.5 min chromatographic run with a LOD of 5ng/mL. The method was applied to routine ketamine urine screening to a maximum of 200 samples per day. 

Other hallucinogenic drugs including substances related to LSD are mentioned under delirium. Phencyclidine and ketamine can also produce similar hallucinatory states without delirium including time distortion, distortion of body image, synaesthesia, visual hallucinations, depersonalisation, derealisation, paranoid ideation and a schizophreniform psychosis which includes the negative symptoms of schizophrenia (Gorelick Balster, 1995). 

The most serious disadvantage to the use of ketamine is its propensity to evoke excitatory and hallucinatory phenomena as the patient emerges from anesthesia. Patients in the recovery period may be agitated, scream and cry, hallucinate, or experience vivid dreams. These episodes may be controlled to some extent by maintaining a quiet reassuring atmosphere in which the patient can awaken or if necessary by administering tran-quilizing doses of diazepam. 

Emergence delirium with restlessness, disorientation and unpleasant dreams or hallucinations may occur for up 24 hours following ketamine administration. Their incidence is reduced by psychological preparation of the patient, avoidance of verbal and tactile stimulation during the recovery period, or by concomitant administration of opioids, benzodiazepines, propofol or physostigmine. However, unpleasant dreams may persist. 

Physicians began administering tranquilizers to block the hallucinations associated with ketamine s emergent state, a condition that refers to the patient s return to consciousness. By both official and unofficial channels, word of the drug s intense hallucinogenic effect spread among doctors, scientists, veterinarians,... 

Research continues to illuminate different aspects of ketamine pharmacology, some of it promising enough to indicate that new clinical uses (principally in the field of anesthesiology) for the drug will be approved. It is still used as a general anesthetic for children and geriatric patients because it is well tolerated. Benzodiazepine-based tranquilizers are used to keep the auditory and visual hallucinations to a minimum. 

At higher doses, ketamine leads to pronounced changes in judgment, distorted vision, auditory hallucinations, such as humming or buzzing, and marked disorientation. Some users report a profound impact on the perception of time, which appears to slow to a complete halt in the emergent, or heavily hallucinatory state. 

Visions of life and death, some calming, others frightening, have been reported. Religious hallucinations, out-of-body experiences, and a pronounced dissociative state that some have called another plane of consciousness are also credited to ketamine. While in what is referred to as K-land or the K-state, users claim to gain insights into their personalities, the people they know, and the workings of the universe. 

Ketamine hydrochloride (Ketalar) is primarily used as an animal tranquilizer. When humans use the drug in a nonmedical setting, ketamine can cause hallucinations, amnesia, and dissociation. It is often used with other drugs such as ecstasy, heroin, or cocaine. Due to widespread abuse by young people, the DEA classified this drug as a Schedule III controlled substance in 1999. 

These molecules cause significant changes in the perceptual system, producing sensory illusions and inducing a distortion of reality, the sense of space and time, to the point of hallucination. Natural, synthetic or semisynthetic substances can cause hallucinogenic effects psilocin, psilocybin, mescaline, and LSD. Hallucinogenic effects are also created by phencyclidine and ketamine, but these molecules have a dissociative character. 

A potentially informative difference between ketamine-induced symptoms and those of schizophrenia is in the production of hallucinations. Thus, in established schizophrenia, auditory hallucinations consisting of voices of various types are common, whereas visual hallucinations are rare. In contrast, during ketamine-induced psychosis, visual perceptual distortions are common but organized auditory... 

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