Ketamine

Ketamine is a chemical compound used as an anesthetic in humans and animals. It was developed decades ago as a less toxic alternative to the drug phencyclidine (PCP), which was also developed as an anesthetic. A ketamine derivative, esketamine (under the brand name Spravato^®), is approved by the U.S. Food and Drug Administration (FDA) for treatment-resistant depression in adults. There is also illicitly manufactured ketamine, sold as a liquid or off-white powder, and commonly called Special K, K, super K, or Vitamin K.  

Ketamine can distort the way a person perceives sights or sounds. A person using it may feel happy, or like they are dreaming or floating outside of their body. At higher doses, a person may feel confused and be unable to move or speak., which is called being in a k-hole.¹  Ketamine can also have other unpleasant or dangerous side-effects. See: “What are the health risks of using ketamine?”

A ketamine derivative, esketamine (under the brand name Spravato^®), is FDA-approved for treatment-resistant depression in adults. Although ketamine is not FDA-approved for any mental health disorder, dozens of clinics across the United States offer it off-label for depression, anxiety, and other conditions. Clinics may offer it in oral form, as a nasal spray, or by intravenous or intramuscular injection, sometimes in combination with psychotherapy. It’s also becoming more common to prescribe ketamine as an alternative to opioids for pain. For more information on ketamine as a therapeutic substance, see “Psychedelic and dissociative drugs as medicines.”

There are many clinics across the United States now offering ketamine, sometimes in combination with psychotherapy. It has been used as recreational drug for decades, particularly at nightclubs and festivals. Research suggests non-clinical ketamine use has increased over the past decade and a half but is still relatively uncommon.²  

• For statistics on ketamine use, see the National Survey on Drug Use and Health from the Substance Abuse and Mental Health Services Administration.
• More information on ketamine use is also available from the NIDA-funded National Drug Early Warning System (NDEWS) network.
• For statistics on ketamine use among adolescents and young adults in the U.S., see the NIDA-funded Monitoring the Future survey.

Ketamine is not currently approved by FDA for the treatment of any substance use disorder. However, ketamine is being investigated as a potential treatment for alcohol use disorder and other substance use disorders, such as opioid use and cocaine use disorder.³  NIDA supports research projects on the safety and effectiveness of ketamine as a treatment for addiction. 

There are potential short- and long-term negative health effects related to ketamine use. These depend on how much ketamine someone takes, whether it is taken with other drugs, and how often or how long ketamine is used.

• Short-term side effects of ketamine use may include headache, dizziness, sleepiness, feeling strange or “loopy,” difficulty speaking, numbness, blurred vision, or nausea. Ketamine may also increase blood pressure or raise heart rate.
• Studies show that unsupervised ketamine use may have serious health risks. These include respiratory depression, which is dangerously slow and shallow breathing. A NIDA-funded study found that problems related to ketamine use reported to poison control centers increased 81% from 2019-2021. The use of other drugs along with ketamine, especially opioids or GHB, another club drug, led to the most health problems, some of them life-threatening.⁴
• Long-term, heavy ketamine use is associated with memory problems, depression, and anxiety. At high doses, ketamine may cause psychosis, a mental illness that causes a person to lose touch with reality. Frequent recreational ketamine use can lead to delusions that can last to up to one month after a person stops using it.⁵
• Long-term use of ketamine may cause gastrointestinal problems, including abdominal pain sometimes called k-cramps. Ketamine use can also cause ketamine-induced uropathy, a treatable but potentially serious condition that causes symptoms like those of a urinary tract infection. 

Laboratory studies show that ketamine use can cause brain changes typical of a drug with addictive potential.⁶  Studies in humans show that regular ketamine use is associated with symptoms of addiction, including continued use despite knowing that it is causing problems, physically hazardous use, using more than intended, spending too much time obtaining or using ketamine, and tolerance, which is when more of a drug is needed for it to have the same effects.⁷  However, more research is needed to determine how addictive ketamine might be.

For more information, see: “Are psychedelic and dissociative drugs addictive?”