Pharmaceutical ketamine is a prescription medication, mostly used in veterinary medicine, but diverted and other illicit forms of the drug are often abused recreationally.1Ketamine is classified as a dissociative drug because it can alter a person’s sense of reality and cause feelings of detachment from one’s body and the environment.2
Ketamine is on the World Health Organization’s list of essential medicines for its use as an anesthetic and analgesic.3 It is considered safer than some other anesthetics because it is less likely to slow down breathing or decrease blood pressure.1,3 Though used in this capacity in low-resource countries and certain emergency settings, people recovering from ketamine anesthesia after surgery may experience negative side effects like extreme confusion, hallucinations, and delusions. For this reason, ketamine is less commonly used with humans but continues to be frequently used in veterinary surgeries.1
Low doses of ketamine can result in perceptual distortions of time and space, hallucinations, and mild dissociation.1,2 At higher doses, it can cause severe dissociation, known by recreational users as a ‘K-hole’—where a person feels completely divorced from reality and their body.1 Users in a K-hole may describe out-of-body or near-death experiences, entering another reality, contacting aliens, or even entering information networks.4 While these sensations may be appealing to some, taking too much ketamine can also lead to memory loss, panic, anxiety, and psychosis.2
Ketamine is sometimes used nefariously by people committing drug-facilitated sexual assault for its ability to cause sedation, memory impairment, and dissociation.2
Ketamine abuse may result in a host of harmful side effects (see below) and may eventually lead to addiction—an inability to stop using despite the harm doing so causes.1,2
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Dangerous Side Effects
Ketamine use may be accompanied by unpleasant and sometimes dangerous side effects such as:1,4
- Memory impairment.
- Persistent perceptual changes.
- Increased heart rate.
- High blood pressure.
- Severe abdominal pain.
- Urinary tract, bladder, and kidney problems.
Another risk of recreational ketamine use is the potential to develop tolerance, physical dependence and/or addiction.1
Tolerance, which results in the need to keep increasing doses to feel the intended effect, appears to be common among regular users. One study found a 600% increase from first dose to current dose among frequent ketamine users.1 Escalating doses may result in increased risks and may also hasten the development of dependence or addiction.
While there is conflicting evidence on whether ketamine use can lead to physical dependence, some research suggests that regular ketamine users who stop taking the drug may experience withdrawal symptoms like heart palpitations, anxiety, sweating, and cravings.1
Those who become addicted and compulsively use ketamine put themselves at risk of serious health issues such as urinary, bladder, and kidney complications. They are also more prone to accidents and death.1,4
Even low doses of ketamine can cause extreme disorientation and confusion in users, which can significantly increase the risk for accidents such as falls or drowning.1,4 This means that driving, operating heavy machinery, and even walking up and down stairs can potentially lead to significant injury while under the influence of ketamine.
Is Overdose Possible?
Overdose on ketamine alone is rare, though a toxic amount of ketamine can cause numerous health problems.1,4 The majority of ketamine-related emergency room visits involve ketamine mixed with other drugs, particularly alcohol, GHB, and MDMA. People presenting to the emergency room report symptoms such as altered consciousness, dizziness, stomach pain, urinary tract issues, increased heart rate, and high blood pressure.1
Taking too much ketamine is particularly risky for people with existing cardiac conditions or hypertension, as ketamine increases cardiac output, causes tachycardia (racing heart rate), and raises the blood pressure.1
The initial psychoactive effects of ketamine typically last between 10 minutes to 4 hours, depending upon the route of administration.4
The ketamine comedown is the drug-induced equivalent of a hangover and begins as the high wears off. People coming down from ketamine may experience serious psychological symptoms, including intense confusion or delirium, hallucinations, and delusions.1
Anecdotal reports of ketamine comedown describe ‘out of body’ experiences or feeling ‘near death.1 People coming down from ketamine are also at risk for agitation, aggression, and violence.5
Medical detox and treatment may be necessary to help safely come down from the drug, minimize severe psychotic symptoms, and manage the risks associated with increased aggression.5
Ketamine and Other Drugs
Ketamine can interact negatively with certain medications and foods, including:6
- Antibiotics like clarithromycin and rifampin.
- Heart medications like ticlopidine.
- Grapefruit juice, which can reduce the drug’s effectiveness.
When ketamine is used recreationally, it is primarily used in club or party settings.1,4 It may be combined with many other substances including cocaine and alcohol. There have also been reports of ketamine being sold as MDMA and being cut into heroin.4 Mixing ketamine with other drugs can put users at risk for additional medical and psychiatric complications:1,5
- Opioids, including heroin and prescription opioids, such as hydrocodone, oxycodone, and morphine, pose a risk for respiratory depression and death.
- Cocaine use can increase the chances of experiencing heart attack, stroke, and other heart-related complications. Because ketamine already increases the risk of cardiac events, taking it with stimulants can be particularly risky.
- Depressants like alcohol, barbiturates, and benzodiazepines, such as Xanax, Klonopin, and Valium, can cause intoxication that may lead to death, particularly if multiple depressants are mixed together.
Other Health Effects
Ketamine is a powerful drug that can result in long-term health effects among chronic users. Psychological problems such as severe anxiety, panic attacks, paranoia, mania, depression, suicidal thoughts, hallucinations, aggression, difficulty sustaining attention, memory impairments, and significant personality changes are all long-term risks of using ketamine. Ketamine use can also cause sleep disturbances like insomnia, nightmares, and night terrors.1,4
Ketamine use over an extended period of time can result in severe urinary tract, bladder, and kidney issues. Ketamine-induced ulcerative cystitis involves frequent and urgent need to urinate, painful urination, and bloody urine. Stopping use and maintaining abstinence from ketamine may provide some relief from these symptoms.
Some chronic ketamine users develop ‘K-cramps,’ which are severe abdominal pains believed to be caused by swallowing drips of the drug when snorted. Long-term ketamine use may also increase the risk for developing bladder cancer, hydronephrosis (renal distension) secondary to urinary obstruction, destruction of kidney cells, and renal failure. 1,3,4
Seeking treatment for ketamine addiction may help alleviate or reverse some of these issues and prevent further problems from developing.
- Morgan, C. J., Curran, H. V. (2012). Ketamine use: A review. Addiction, 107(1), 27-38.
- National Institute on Drug Abuse. (2019). DrugFacts: Hallucinogens.
- World Health Organization. (2016). Fact file on ketamine.
- Dillon, P., Copeland, J., & Jansen, K. (2003). Patterns of use and harms associated with non-medical ketamine use. Drug and Alcohol Dependence, 69(1), 23-28.
- Substance Abuse and Mental Health Services Administration. (2013). Detoxification and substance abuse treatment.
- Quibell, R., Fallon, M., Mihalyo, M., Twycross, R., & Wilcock, A. (2015). Ketamine. Journal of Pain and Symptom Management, 50(2), 268-278.