Medically, ketamine is used for the induction and maintenance of anesthesia; it is also abused as a recreational drug. Ketamine is a novel compound, derived from PCP. Ketamine may additionally be utilized for acute pain management.
Ketamine was first synthesized in 1962; in 1970 it was approved for use in the United States. It has been regularly applied in veterinary medicine and in the Vietnam War it was widely used for surgical anesthesia.
At sub-anesthetic doses, ketamine produces a sense of detachment from one’s own body that is known as depersonalization. When abused as a recreational drug, it is found both in powder and liquid form, and is often referred to as “Special K” for its hallucinogenic and dissociative effects.
Ketamine is a promising agent for treatment-resistant depression; however, the antidepressant action of a single administration of ketamine decreases with time. The long-term effects of repeated use are largely unknown, and an area of current investigation.
Because of its ability to cause confusion and amnesia, ketamine has come to be known as a “date rape drug.” At high doses, users may experience what is called the “K-hole”, a state of dissociation with both visual and auditory hallucinations.
Recreational ketamine abuse has been implicated in deaths globally, with more than 90 deaths in England and Wales from 2005 to 2013. These included accidental poisonings, drownings, traffic accidents, and suicides; the majority were among young people.
At anesthetic doses, 10–20% of adults experience adverse reactions during emergence from anesthesia, ranging from hallucinations to emergence delirium.
Dizziness, blurred vision, dry mouth, hypertension, nausea, and feeling flushed are the most common (>10%) side effects. All these adverse effects are dramatically reduced 40 minutes after the injection, and completely disappear within 4 hours.
At very low, sub-anesthetic doses, most people feel strange, spacey, woozy, a sense of floating, or have visual distortions or numbness. Also very frequent (20–50%) are difficulties speaking, confusion, euphoria, drowsiness, and trouble concentrating.
Symptoms of psychosis such as disappearing, feeling as if melting, “experiencing” colors, and hallucinations are described by 6–10% of people.
Although the actual incidence of ketamine dependence is unknown, some people who regularly use ketamine develop ketamine dependence. The short duration of ketamine’s effects promotes binging on the drug. Ketamine tolerance rapidly develops, even with medical usage, prompting the use of higher doses.
Cognitive deficits as well as increased dissociation and delusion symptoms were observed in frequent recreational users of ketamine. Some daily users reported withdrawal symptoms, primarily anxiety, shaking, sweating, and heart palpitations, following the attempts to stop.