- Also called:
- 2-(2-chlorophenyl)-2-(methylamino)-cyclohexanone or CI581
- Related Topics:
- hallucinogen
- major depressive disorder
- intravenous anesthetic
- On the Web:
- Verywell Mind - K-Hole and the Effects of Ketamine (Oct. 16, 2026)
ketamine
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What is ketamine?
Ketamine is a general anesthetic, synthesized in 1962 while seeking a safer alternative to PCP. Approved for human use in the U.S. in 1970, it saw use during the Vietnam War. While it can have minor hallucinogenic side effects in humans, ketamine is now more commonly used as a veterinary anesthetic. It is still valuable in human medicine, especially for children or minor surgeries, and to treat depression and chronic pain.
Ketamine induces a dissociative state, providing pain relief, sedation, and amnesia without depressing respiration. It alters brain activity by inhibiting neurotransmitter uptake, disrupting communication between the thalamus and cerebral cortex, and stimulating the limbic system. Side effects include tearing and, less often, hallucinations, especially in adults. Recreational use can lead to hallucinations, amnesia, impaired judgment, and long-term cognitive issues.
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What was ketamine first used for?
Ketamine, synthesized in 1962 by American scientist Calvin Stevens at Parke Davis Laboratories, was initially created as an anesthetic to replace phencyclidine (PCP), due to PCP's severe hallucinogenic effects. Ketamine was patented in Belgium in 1963 and approved by the U.S. Food and Drug Administration in 1970. It was used to treat American soldiers during the Vietnam War. While it can produce minor hallucinogenic side effects, ketamine is now often used as a veterinary anesthetic. It also has applications in human medicine, particularly for children and minor surgeries, and may be used to treat depression and chronic pain.
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How does ketamine affect the human body?
Ketamine is a general anesthetic that impacts the human body by altering neuron activity in the brain. It inhibits neuronal uptake of neurotransmitters like serotonin, glutamate, and dopamine, depressing neural communication between the thalamus and cerebral cortex and uncoupling brain activity tied to memory, motor function, sensory experience, and emotion. Ketamine induces a dissociative state characterized by analgesia, hypnosis, and amnesia, often accompanied by open eyes, involuntary limb movements, and jumping eye movements.
Ketamine can cause minor side effects such as tearing. Higher doses can produce delirium and hallucinations. Ketamine's hallucinogenic effects have led to its recreational abuse, with users seeking a separation of mind and body, referred to as the "K hole." Long-term abuse may result in cognitive dysfunction, paranoia, and depression. High doses can cause unconsciousness, cardiovascular depression, and even death.
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Why do doctors sometimes use ketamine in hospitals?
Doctors sometimes use ketamine in hospitals as an anesthetic, especially for children or minor surgeries. It's also used to treat depression and chronic pain. Unlike other anesthetics, ketamine doesn't depress respiration or central nervous system functions, giving it a wide safety margin. It provides pain relief, sedation, and amnesia, inducing a dissociative state characterized by unconsciousness and increased muscle tone. Ketamine works by altering neuron activity in the brain, depressing neural communication, and uncoupling brain activity associated with memory, motor function, sensory experience, and emotion.
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What are some risks or side effects of taking ketamine?
Ketamine, while valuable in human and veterinary medicine as an anesthetic, carries risks and side effects. Though it has a relatively wide margin of safety because it does not depress respiration, ketamine can induce minor hallucinogenic side effects like intense dreams and delirium upon waking, especially in adults. Higher doses can intensify these effects.
Recreational use of ketamine can lead to symptoms of amnesia, schizophrenia, impaired judgment, and lack of coordination that can last for days. Long-term abuse may result in paranoia, depression, and cognitive dysfunction. High doses can also cause unconsciousness, cardiovascular depression, and even death.
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How is ketamine used today outside of surgery or anesthesia?
Outside of surgery and anesthesia, ketamine has valuable applications in human medicine today. It can be used to treat depression and chronic pain. As an N-methyl-d-aspartate receptor (NMDAR) antagonist, ketamine may also treat neuropathic pain like diabetic neuropathy by blocking NMDAR activation involved in nociceptive transmission.
However, ketamine can produce minor hallucinogenic side effects in humans. The ability of ketamine to produce hallucinogenic effects has led to its abuse as a recreational drug, known by street names like K, Special K, and cat valium.
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ketamine, general anesthetic agent related structurally to the hallucinogen phencyclidine (PCP). Ketamine was first synthesized in 1962 at Parke Davis Laboratories by American scientist Calvin Stevens, who was searching for a new anesthetic to replace PCP, which was not suitable for use in humans because of the severe hallucinogenic effects it produced upon recovery of consciousness. Ketamine was originally patented in Belgium in 1963 and was approved for use in humans by the U.S. Food and Drug Administration in 1970. Soon after, it was put to use to treat American soldiers fighting in the Vietnam War. Today, since ketamine can produce minor hallucinogenic side effects in humans, it is used most often as a veterinary anesthetic. However, the drug does have valuable applications in human medicine, especially as an anesthetic for children and for individuals undergoing minor surgery. It may also be used to treat depression and chronic pain.
Unlike inhalation anesthetics or sedative anesthetics (e.g., narcotics and benzodiazepines), ketamine does not depress respiration or other basic functions of the central nervous system. Thus, ketamine has a relatively wide margin of safety. In addition, it is distinct from other anesthetics because it has three major effects: analgesia (pain relief), hypnosis (sedation), and amnesia. The drug is known particularly for its ability to induce a dissociative (cataleptic) state, which is characterized by a lack of pain sensation, unconsciousness, and increased muscle tone. These characteristics are often accompanied by open eyes, jumping eye movements (nystagmus), and involuntary limb movements.
Ketamine works by altering the activity of neurons in the brain. This is accomplished through the drug’s inhibition of neuronal uptake of various neurotransmitters, including serotonin, glutamate, and dopamine. The net effect is a depression of neural communication between the thalamus and the cerebral cortex, resulting in an uncoupling of brain activity associated with memory, motor function, sensory experience, and emotion. Ketamine also stimulates activity in the limbic system, a region of the brain involved in controlling certain autonomic functions and in integrating various brain activities, including those associated with motivation and emotion.
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In clinical use ketamine is administered intramuscularly or intravenously. Minor side effects of the drug include tearing (lacrimation) when emerging from the dissociative anesthetic state. Patients can sometimes experience severe and troubling hallucinogenic effects, such as intense dreams and delirium, upon waking; these effects are more common in adults than in children. Hallucinations are directly related to dose. Thus, higher doses produce more pronounced delirium and other symptoms of hallucination than do lower doses.
Ketamine’s ability to produce hallucinogenic effects within minutes after administration has led to its abuse as a recreational drug. The dissociative effect of ketamine that is produced by high doses is often described by recreational users as the “K hole”—a separation of the mind and body, or a hallucinatory “out of body” experience. Ketamine is known by various street names, including K, special K, jet, super acid, and cat valium. It may be snorted, injected, or taken orally, and its effects may last from 30 minutes to more than an hour. However, for one or more days after taking the drug, users may display symptoms of amnesia, schizophrenia, impaired judgment, and lack of coordination. In addition, long-term abuse can lead to paranoia, depression, and other evidence of cognitive dysfunction. Many individuals appear to be in a stupor when the drug has been taken in low doses; however, high doses can cause unconsciousness, cardiovascular depression, and death.