What Is Ketamine?

An Anesthetic Drug That Can Also Be Abused

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Ketamine, also called ketamine hydrochloride, is an injectable medication that is given for surgical anesthesia. Ketamine is usually used along with other anesthetic medications during surgery, but it can be used alone for pain control during certain procedures that don’t require muscle relaxation.

During your operation, you would have your vital signs monitored while you are receiving ketamine to minimize the risk of medication-induced side effects. Aside from its medical use, ketamine is also a drug of abuse, and it can cause dangerous health issues when it is used for illegal, non-medical purposes.

Ketamine is used in surgical anesthesia
SDI Productions / E+ / Getty Images 

What It Is

Ketamine reduces certain nervous system functions by inhibiting normal N-methyl-D-aspartate (NMDA) receptor activity. Normally, NMDA receptors, which are located on the surface of nerve cells, bind to neurotransmitters to modulate the actions of the nervous system.

Ketamine is an NMDA receptor antagonist. It counteracts the effects of NMDA receptors in the body by blocking them. Ketamine is available in a generic formulation and as the brand Ketalar.


Ketamine has a rapid action that diminishes sensation, prevents pain, induces sleep, and inhibits memory. This drug can cause a sense of dissociation from reality and may lead to fleeting hallucinations. 

If your anesthesiologist administers ketamine as part of your anesthesia regimen, you may have hallucinations when you are falling asleep for your procedure.

Additionally, ketamine can cause you to be briefly confused after waking up from surgery. Most people do not remember the early or late phases of ketamine on thinking and memory and can’t recall having had hallucinations or confusion.

Ketamine works very quickly once it enters the body. It can have effects within seconds, and the effects wear off within 15 to 20 minutes. This action can differ for people who have medical issues, such as liver disease or kidney impairment.


Ketamine is used as an anesthetic in surgery for adults and children. It is used in major and minor surgeries and for planned and emergency procedures.

Ketamine can be administered during abdominal operations, orthopedic procedures, surgical burn treatment, some dental procedures, and many other types of surgery. This medication is used for different types of anesthesia, including general anesthesia and spinal anesthesia.

There are a number of different anesthetic medications, and ketamine is usually used along with other anesthetics. If you are having surgery, your anesthesiologist will administer a combination of anesthetics for these reasons:

  • A combination of medications helps to avoid high doses of individual medications, which can result in adverse effects of anesthesia.
  • The different anesthetics used for a surgical procedure have slightly different effects and duration of action.

Ketamine is among the faster-acting and shorter-duration anesthetics. It controls pain, but it doesn’t decrease muscle tone. Most surgeries also require anesthetics that reduce muscle tone and movement.

Benefits for Surgery

One of the advantages of ketamine in the surgical setting is that ketamine does not have a substantial effect on breathing or heart function. Ketamine has also been associated with high levels of satisfaction after surgery, and research suggests that this could be due to a reduction in post-operative pain. 

Ketamine is also used for anesthesia in a range of veterinary procedures, such as for dogs, cats, and other animals.


Ketamine has also been used for treatment of refractory status epilepticus. This is a dangerous type of seizure that requires emergency treatment with anti-seizure medication.

Ketamine is not a first line treatment for status epilepticus, and it is generally used when other treatments are contraindicated or when they have not effectively stopped a prolonged seizure. 


Ketamine injection has also been investigated in research studies as a potential treatment for depression and suicidal ideation, with promising results. Currently, ketamine is not approved for treating depression. A similar drug, Spravato (esketamine), which is used as a nasal spray, was approved for treating depression in 2019.

How It Is Used

Ketamine is injected intravenously (IV) or intramuscularly (IM, in a muscle) when used for surgery. It is typically used for anesthesia induction before other anesthetic drugs are administered.

The initial IV dose of Ketalar ranges from 1 milligram (mg) per kilogram (kg) of body weight to 4.5 mg per kg of body weight. The initial dose for anesthesia induction is administered over several minutes.  

Ketamine has a fast onset of action and a short duration of action, so it starts working within minutes and wears off fairly quickly. When ketamine is given for anesthesia during long surgical procedures, repeated dosing is necessary. 


Ketamine should only be used in a setting when an anesthesiologist will be monitoring health and vital signs. Ketamine can have side effects, including changes in blood pressure. This drug may be contraindicated for you if your blood pressure is unstable.


In addition to its medical use, ketamine has also been a drug of abuse. This medication has been known to be sold illegally in various forms, which can be taken in different ways.

When it is abused, the main effects are hallucinations and dissociation from reality, but the effects of the drug when it is used for non-medical purposes are not as predictable or controllable as its effects during monitored anesthesia.

Overdose and adverse effects of illegal ketamine use include nervousness, chest pain, seizures, and psychosis. Prolonged or repeated use can lead to psychiatric issues, including psychosis and flashbacks.

Additionally, ketamine has also been abused for criminal purposes when it is given to a person who is unaware that they are being given the drug. In these circumstances, the drug alters the awareness and consciousness of the unknowing recipient, and it has been used for crimes against the recipient, such as sexual assault. 

A Word From Verywell

If you are having surgery, you might receive ketamine as one of your anesthetic medications. As you wake up from your surgery, the effects of ketamine are among the reasons why you won’t remember the procedure. This medication is considered safe and may reduce the need for post-operative pain medication.

Ketamine does not cause any persistent problems when it is used for anesthesia. However, if you have abused ketamine for a non-medical use, it can harm your health, and you need to seek urgent medical help.

If you are dealing with a ketamine addiction, you will need professional help to manage the physical and psychological effects of your addiction. And if you think that you may have unwillingly received this drug, it’s important that you promptly seek medical attention. 

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Ketalar label.

  2. Vincenzi P, Starnari R, Faloia L, et al. Continuous thoracic spinal anesthesia with local anesthetic plus midazolam and ketamine is superior to local anesthetic plus fentanyl in major abdominal surgery. Surg Open Sci. 2020;2(4):5-11. doi:10.1016/j.sopen.2020.07.002

  3. M, Rasooli F. Comparison of the efficacy of ketamine- propofol versus sodium thiopental-fentanyl in sedation: a randomised clinical trial. Emerg Med J. 2021;38:211-216. doi:10.1136/emermed-2020-209542

  4. Alkhachroum A, Der-Nigoghossian CA, Mathews E, et al. Ketamine to treat super-refractory status epilepticus. Neurology. 2020;95(16):e2286-e2294. doi:10.1212/WNL.0000000000010611

  5. Sakurai H, Jain F, Foster S, et al. Long-term outcome in outpatients with depression treated with acute and maintenance intravenous ketamine: A retrospective chart review. J Affect Disord. 2020;276:660-666. doi:10.1016/j.jad.2020.07.089

  6. Food and Drug Administration. Spravato label.

  7. Zhang C, Xu Y, Zhang B, Hao W, Tang WK. Cognitive impairment in chronic ketamine abusers. Psychiatry Res. 2020;291:113206. doi:10.1016/j.psychres.2020.113206

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.