Dissociative Anesthetics

Dissociative Anesthetics cause a feeling of mind dissociating from the body. The mind takes a trip to a far of place wile the body remains in the current position. Of course this is just a feeling and it never actually happens. 
Phencyclidine (PCP), ketamine, γ-hydroxybutyrate (GHB), dextromethorphan (found in cough suppressants), Salvia divinorum, and propofol—are hallucinogens.
Salvia is a pure hallucinogen. It has no known anesthetic effects. Patients who are given Phencyclidine (PCP) or ketamine do experience anesthetic effects; they remain conscious but exhibit no apparent response to surgical pain. The same is also true of γ-hydroxybutyrate (GHB). None of these anesthetic agents produces muscle relaxation and neither does propofol. As a consequence, when any of these drugs is used at surgery (either human or animal), other agents must be administered to produce muscle relaxation. Salvia induces neither anesthesia nor muscle relaxation. Salvia abuse has become more widespread. It can easily be purchased over the Internet (or even grown in the backyard). The first Salvia-related fatalities have yet to be reported, but occasional episodes of death and morbidity have been attributed to the other dissociative drugs, most notably that of the famous pop star, Michael Jackson (died due to propofol overdose).
Ketamine does not depress the heart and therefore good anesthetic for patients with heart problems.
PCP is the most commonly abused member of the group, and probably the most dangerous as well. Massive doses of phencyclidine(PCP) can cause rhabdomyolysis and death, while large doses of γ-hydroxybutyrate (GHB) and propofol can induce transient (but potentially fatal) respiratory paralysis. One dies from lack of air (hypoxia). However, taken as a group, the principal toxic effects exerted by these drugs are psychiatric. Considerable attention has been devoted to the use of γ-hydroxybutyrate in drug-facilitated sexual assault, but the magnitude of the problem is difficult to assess and probably overblown by the media. The few studies that have been performed suggest that the use of these drugs to facilitate sexual assault is very low.
Methamphetamine and PCP both induce psychotic states nearly indistinguishable from schizophrenia, and ketamine does the same (Krystal et al., 1994). NMDA glutamate receptor antagonists, including PCP, ketamine, GHB, and DXM, all produce a state of dose-dependent disinhibition where NMDA antagonists abolish GABAergic inhibition. GABAergic inhibition probably explains the addictive nature of  propofol and the evidence of sexual excitation sometimes seen on emergence from 
propofol sedation; where there is simultaneous and excessive release of acetylcholine and glutamate, the NMDA receptor itself becomes less functional. Progressive loss of the NMDA receptor function, even when induced by relatively low doses of NMDA antagonist drugs, can lead to specific forms of memory dysfunction, with or without clinical psychosis. If NMDA function is severely reduced, the result can be a clinical syndrome very similar to a psychotic exacerbation of schizophrenia. Large doses of NMDA(N-methyl-D-Aspartate, a neurotransmitter in the brain) inhibitors, administered over a long time, can lead to histopathologic changes (Farber, 2003).
Phencyclidine (PCP)
Effects of Phencyclidine are related to those of ketamine. It was initially used as anesthetic in humans and is still used in animals.
PCP can be injected, swallowed, snorted or smoked.
Effects of Phencyclidine
Phencyclidine causes death of brain cells by inducing apoptosis (programed cell death-self destruction). This may be the mechanism by which it causes epilepsy when used for a long time.
Methoxetamine is structurally related to PCP.  It is a noncompetitive NMDA receptor antagonist as well as a dopamine reuptake inhibitor, and an agonist at dopamine D2. The good feeling induced by haze is due to effects of retained dopamine and agonism at D2 receptor.
The drug causes catatonia and dissociation
Ketamine is a very available drug as it can be sold by pharmacists who don’t follow the law. It is used as an anesthetic.  It is available as an injection.
The analgesic effects of ketamine can be explained by its ability to bind to μ opioid and σ receptors. But, like PCP, ketamine also blocks the NMDA receptor, a receptor classified by some as a subtype of the σ opiate receptor.
Ketamine is a relatively safe drug. It only affects the lower urinary tract symptoms.
Gamma-Hydroxybutyrate and Related Substances.
Gamma-Hydroxybutyrate (GHB) is a simple hydroxy acid and a significant drug of abuse. Overdose of Gamma-Hydroxybutyrate has been reported to cause death.
Available under several brand names. It is used in treatment of neuralgic pains and as anticonvulsant. Pregabalin binds to the alpha-2-delta subunit of the voltage-dependent calcium channel in the CNS, decreasing the release of glutamate, noradrenaline, substance P, and calcitonin gene–related peptide.
The drug has been associated with abuse, particularly in persons dependent on or withdrawing from opioid abuse.
Propofol is used as a general anesthetic. Propofol can also cause sleep in small doses.
Propofol causes profound hypotension but this is not an issue in surgery as it is used together with ketamine.
Effects of propofol
Mild euphoria, sometimes associated with hallucinations, and sexual disinhibition may occur. This type of behavior is modulated by the dopaminergic system in the nucleus accumbens and by the glutamatergic system in the neocortex and limbic region. Whether any distinctive neuropathologic lesion (besides those associated with anoxia) occurs is not known.

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