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Clues Revealed by Ketamine
Published in Scott Mendelson, Herbal Treatment of Major Depression, 2019
The term, “hole” or “fall through the K-hole” refers to the point of ego dissolution that some experience with high doses of the drug. Considering that ketamine is an old anesthetic known to produce frightening, even psychotic, symptoms in some people, it has seemed an unlikely candidate for a psychiatric breakthrough. However, at doses lower than those generally used for anesthesia – or out of intent to “fall through the K-hole” – the drug can produce remarkable effects in individuals suffering severe, intractable depression.
Misuse, Recreational Use, and Addiction in Relation to Prescription Medicines
Published in Ornella Corazza, Andres Roman-Urrestarazu, Handbook of Novel Psychoactive Substances, 2018
Francesco S. Bersani, Claudio Imperatori
Similarly to propofol, the major driving forces of ketamine recreational use are the ketamine-induced dissociative symptoms, mainly due to its pharmacodynamic action on the glutamatergic transmission, i.e., NMDA antagonism (Tyler et al., 2017). As pointed out by Schifano et al., at low doses, ketamine’s stimulant effects predominate; with higher doses, its psychotropic effects range from referential thinking, dissociation, and depersonalization to psychotic experiences and include a sensation of feeling light, body distortion, absence of time sense, novel experiences of cosmic oneness, and out-of-body experiences, often called the ‘K-hole’ (Schifano et al., 2008). Potential acute intoxication symptoms include depression of the CNS, severe psychomotor agitation, rhabdomyolysis, abdominal pain, and lower urinary tract symptoms, while potential adverse effects related to its chronic use include psychosis, cognitive impairment, and addiction (Hernandez & Nelson, 2010; Tyler et al., 2017).
Hallucinogens
Published in G. Hussein Rassool, Alcohol and Drug Misuse, 2017
Ketamine users report sensations of “dissociative effect” ranging from a pleasant feeling of floating to being separated from their bodies. A giddy euphoria occurs with lower doses, often followed by bursts of anxiety or mood lability. Some ketamine users’ experiences involve a terrifying feeling of almost complete sensory detachment that is likened to a near-death experience. These experiences, similar to a “bad trip” on LSD, are called the “K-hole”. These sought-after effects are strongly dose related and may last up to two hours.
A primer on sleeping, dreaming, and psychoactive agents
Published in Journal of Social Work Practice in the Addictions, 2023
Ketamine, a glutamate receptor antagonist, is used clinically, primarily in developing nations, as an anesthetic, though more recently has become popular as an anti-depressant for treatment-resistant individuals. Thus, it, like PCP, has potent sedative effects that can not only disorientate a user but also induce sleep. When ketamine is used in surgery, recovery tends to be slower than when other anesthetics are employed (Schwenk et al., 2018). Violent dreams and flashbacks have been associated with both clinical and non-medical use of the drug. In larger doses, the ‘K-hole’ effect occurs a distinct feeling of mind and body separation that in severe circumstances can lead to stupor or unconsciousness, with a resulting feeling of confusion and loss of short-term memory. Some have equated this to an out-of-body or near-death experience. Ketamine use increases nREM intensity and duration, and while it does not increase or decrease REM sleep, ketamine use does tend to produce more vivid and violent dreaming (Feinberg & Campbell, 1993; Hejja & Galloon, 1975).
Long-term safety of ketamine and esketamine in treatment of depression
Published in Expert Opinion on Drug Safety, 2022
Sina Nikayin, Eva Murphy, John H. Krystal, Samuel T. Wilkinson
In our experience, a majority of patients experience dissociation to some degree, though it is rarely problematic. On rare occasions, patients can experience pronounced dysphoria that is associated with the dissociative experience. These experiences seem to be similar to what is sometimes described in the literature on ketamine abuse as a ‘K-hole.’ Anecdotal descriptions by patients include the following accounts [24]: I had an out of body experience that was really scary.
Harm related to recreational ketamine use and its relevance for the clinical use of ketamine. A systematic review and comparison study
Published in Expert Opinion on Drug Safety, 2022
Jan Van Amsterdam, Wim Van Den Brink
Common and clinically relevant adverse effects experienced at clinical doses of 0.5–1.0 mg/kg i.v. are among others psychotomimetic, cardiovascular, and neurological effects, including headache, dizziness, dissociation, increased blood pressure and heart rate, blurred vision, nausea, sedation/drowsiness, and/or anxiety [5,6,24,43,81]. Note that, in contrast to recreational users who are familiar with ketamine’s k-hole, patients might experience this effect as an SAE. Common adverse events in the previously mentioned Phase 3 depression study were of mild or moderate severity (dizziness, dissociation, dysgeusia, vertigo, and nausea), and well tolerated as they were transient and resolved the same day [79,80,82]. This was also concluded by Short et al. [24] in their systematic review about ketamine’s side effects that encompassed 902 patients who had depression and had received at least one dose of ketamine of whom 356 had received multiple doses. They described acute ketamine psychiatric side effects in 38% of studies, whereas psychotomimetic or dissociative side effects were described in 72% of the studies, but no long-term psychotomimetic side effects or signs of drug dependency were reported [24]. The adverse effects described were, however, not clinically significant because they were mostly mild, transitory, and spontaneously resolved within 30 minutes to 2 hours after ketamine administration [24,43,83]. Studies on ketamine given for longer time periods (20–80 days) to treat chronic pain suggested that oral ketamine may be acceptable in terms of tolerability and side effects [74]. A survey, among 6,630 patients with depression who received repeated parenteral administration of ketamine (one-third of them received more than 10 doses), reported a low rate of adverse effects and no dependency to ketamine, suggesting that long-term treatment of depression with ketamine is relatively safe [84]. However, there is a lack of data about the side effects during and following repeated administration of ketamine at higher doses [6].