What Is Ketamine?

Ketamine is an injectable anesthesia that has been used in humans and animals since 1970. It is referred to as a "dissociative anesthetic hallucinogen" because it makes people feel detached from their pain and surroundings.

Aside from its medical use as an anesthetic, ketamine is prescribed by some healthcare providers as an alternative treatment for severe depression. The Food and Drug Administration (FDA) has not approved ketamine as a treatment for any psychiatric disorder. The only FDA-approved option is Spravato, a nasal spray made from a derivative of ketamine, which is used for treatment-resistant depression in adults.

Ketamine is also used as a recreational drug that can be abused for its dissociative sensations and hallucinogenic effects.

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 as ketamine hydrochloride, in a generic formulation and as the brand Ketalar.

Effects

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.

Uses

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. 

Epilepsy

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. 

Depression

Researchers are investigating ketamine as a potential treatment for depression and suicidal ideation, with promising results. Currently, ketamine is not FDA-approved for treating any psychiatric disorder. A similar drug, the nasal spray Spravato (esketamine), is approved in combination with an oral antidepressant for treatment-resistant depression.

Off-label Uses

Before Spravato was approved in 2019, ketamine was prescribed off-label for the treatment of depression. Other off-label uses of ketamine include treating bipolar disorder, post-traumatic stress disorder, as well as substance use disorder.

Dosage and Administration

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. 

Risks

Ketamine should only be used in a clinical setting under the supervision of a healthcare provider. Ketamine can have side effects, including changes in blood pressure. This drug may be contraindicated for you if your blood pressure is unstable.

Abuse 

In addition to its medical use, ketamine has also been a drug of abuse. Commonly known as "Special K," the drug can be injected or used in its powder form that is snorted, smoked, or mixed into drinks.

At very high doses, users may experience unwanted side effects such as paranoia, increased blood pressure, and unconsciousness.

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

Additionally, ketamine has been abused to facilitate 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.