How Many People Die From Ketamine Use?

Ketamine-involved deaths in the United States have been climbing in recent years, though the absolute numbers remain far smaller than those linked to opioids or stimulants. Between 2020 and 2023, the CDC’s State Unintentional Drug Overdose Reporting System (SUDORS) recorded a total of 865 ketamine-positive deaths, with the annual count rising from 175 to 320 over that span. Those figures tell only part of the story, because the way people die with ketamine in their system is rarely as simple as “ketamine overdose.”

How Many Deaths Show Up in U.S. Data

The most recent national accounting comes from SUDORS, which tracks unintentional and undetermined-intent drug overdose deaths across participating U.S. states and territories. In 2020, there were 175 ketamine-positive deaths, a rate of roughly 0.11 per 100,000 people. By 2023 that count had nearly doubled to 320, or about 0.15 per 100,000. Researchers noted, however, that the increase was not statistically significant when population growth and expanded reporting were factored in.¹ To put those numbers in perspective, fentanyl and other synthetic opioids kill tens of thousands of Americans every year. Ketamine fatalities remain a small fraction of the drug-death landscape, which is one reason they have historically received less attention from surveillance systems and may be undercounted.

A systematic review that pulled together case reports and forensic studies from around the world found 138 deaths and 312 overdose cases linked to ketamine or its chemical relatives. In both fatal and nonfatal cases, ketamine itself was the dominant substance involved, showing up in roughly 89% of the deaths and 79% of overdoses.² That review spanned decades of published literature, so the total count is modest compared to surveillance data, but it confirms that ketamine can be directly lethal and that it is usually the primary substance rather than a bystander on the toxicology report.

Why Most Ketamine Deaths Are Not Pure Overdoses

A common misconception is that ketamine kills the same way heroin or fentanyl does, by shutting down breathing until the person suffocates. Ketamine can depress respiration at high doses, but its more typical danger profile is different. In England, where recreational ketamine use has been tracked since the late 1990s, accidental poisoning accounted for about three-quarters of ketamine-related deaths notified to the national monitoring program between 1997 and 2019.³ The remaining quarter included cases in which ketamine appeared to impair judgment, leading to drownings, falls, hypothermia, or traffic accidents. This split matters: when people imagine a “ketamine death,” they picture someone unconscious on a floor, but a sizable share of these deaths happen because the drug puts a person in a dissociative state and they wander into a dangerous situation.

A seven-year national study from Taiwan examined consumption patterns in forensic cases that tested positive for ketamine. Drug intoxication was the leading cause of death, followed by traffic accidents. The concurrent use of ketamine and alcohol alone accounted for nearly half of the deaths from both drug intoxication and traffic crashes.⁴ Ketamine’s dissociative effects can make someone unable to recognize danger, coordinate movement, or respond to environmental threats. That impaired-judgment pathway is distinct from respiratory depression and is harder to prevent with typical overdose-response measures like naloxone.

The Polydrug Problem

Almost every large study of ketamine-related deaths finds that most decedents had other substances in their systems. In the Taiwanese data, the most common pattern was ketamine combined with alcohol, appearing in about half of all cases. Ketamine combined with new psychoactive substances showed up in roughly 39% of cases, and ketamine plus methamphetamine in about a quarter.⁴ These are not minor footnotes. The combination of substances often transforms a survivable experience into a fatal one.

Ketamine and alcohol share several targets in the brain, and researchers have hypothesized that using both together can amplify toxicity well beyond what either substance would cause alone.⁵ The pairing is especially dangerous for motor control and consciousness: both drugs cause sedation and disorientation, so their overlap deepens the dissociative hole and raises the odds of aspiration, falls, and vehicle crashes.

The interaction with opioids deserves its own mention. Preclinical and clinical studies have shown that ketamine can intensify the oxygen-starving effects of fentanyl on the brain. While ketamine on its own tends to increase brain oxygenation, combining it with intravenous fentanyl modestly worsened the hypoxia fentanyl caused.⁶ Given that illicit ketamine is sometimes consumed alongside opioids, and given that street drug supplies are increasingly contaminated with fentanyl, this interaction is a growing concern. A person who normally tolerates a certain dose of ketamine can face a very different risk if fentanyl is also present.

How Safe Is Ketamine in Medical and Psychiatric Settings

Ketamine has a long and generally reassuring safety record when administered by trained professionals. A systematic review of psychiatric studies that used sub-anesthetic doses of ketamine for depression and other mental health conditions found that out of 3,756 patients who received at least one dose, only four experienced a medically serious adverse event, roughly 0.1% of individuals. All four recovered without lasting effects, and no deaths were reported in any of the reviewed trials.⁷ That number carries a caveat, though: most of the trials screened out people with significant cardiovascular risk, so the 0.1% rate may not apply to the broader population of people seeking ketamine therapy.

In intensive-care settings, a study of critically ill patients on mechanical ventilation found no significant difference in 28-day or 90-day death rates between those who received ketamine and those who did not. Among certain subgroups, including younger patients and those with acute respiratory distress syndrome, ketamine was actually associated with lower short-term mortality.⁸ The drug has been a fixture in emergency medicine and anesthesia for decades precisely because it preserves airway reflexes and breathing better than many alternatives.

Pre-hospital use tells a slightly more nuanced story. A review of out-of-hospital ketamine administration, covering more than 10,000 patients, found that ketamine could not be ruled out as a contributing factor in two on-scene deaths, about 0.02% of recipients. Among patients who later died in the hospital, the drug could not be excluded in six deaths, or about 0.3% of those with hospital follow-up data.⁹ Those rates are low, but the review also found that nearly one in six patients developed elevated carbon dioxide levels after ketamine was given, and about 8% had drops in blood oxygen. These complications are manageable when a paramedic is watching, but they underscore that ketamine is not without physical risk even in professional hands.

Why Some People Clear Ketamine More Slowly

One underappreciated factor in ketamine safety is genetic variation in how quickly a person’s body breaks the drug down. Ketamine is primarily metabolized by a liver enzyme, and the gene that codes for that enzyme comes in several versions. People who carry two copies of a slower-functioning variant cleared ketamine at less than a third of the rate seen in people with the standard version. Those with one slow copy and one standard copy fell somewhere in between.¹⁰ Age compounds this: older patients also cleared the drug more slowly, and when advanced age and the slow-metabolizer genotype overlapped, the two factors together accounted for about 60% of the variation in how much ketamine accumulated in the blood.

Slower clearance means higher blood levels for the same dose, which translates into a greater chance of side effects. The study found that patients who experienced adverse effects had lower clearance rates than those who did not. In a clinical setting, a physician can adjust the dose. In recreational use, where people dose themselves without knowing their metabolizer status, this genetic lottery creates uneven risk. Two friends taking the same amount from the same batch can have vastly different experiences, and for a slow metabolizer, a “normal” recreational dose could push blood levels into a dangerous range.

Chronic Use and Long-Term Organ Damage

Ketamine-related deaths are not always acute events. Chronic heavy use can cause serious damage to multiple organ systems, and some of that damage can prove fatal over time. Case reports document patients with severe wasting, liver dysfunction, kidney injury, and extensive damage to the urinary tract after prolonged ketamine abuse.¹¹ The urinary tract effects are among the most distinctive: frequent ketamine use can inflame and shrink the bladder to the point where a person urinates dozens of times a day, sometimes with blood. This condition, sometimes called “ketamine bladder,” can progress to the point of requiring surgical intervention.

The gastrointestinal tract is another target. Chronic users sometimes develop severe abdominal cramping, referred to as “K-cramps,” which can be intense enough to send people to the emergency room. Liver and bile duct abnormalities have also been documented. While these conditions are not immediately lethal in the way an overdose is, they erode health progressively and can create life-threatening crises like acute kidney failure or sepsis from urinary tract infections. Deaths from these complications rarely get counted in overdose statistics, which means the full toll of chronic ketamine use is almost certainly undercounted.

Ketamine, Suicide Risk, and a Clinical Paradox

Ketamine has gained attention as a rapid-acting treatment for suicidal thoughts, and clinical trials do show that supervised, low-dose infusions can temporarily reduce suicidal ideation. But research on recreational and unsupervised ketamine use tells a different story. A study of adults in Taiwan found that people who had recently used ketamine showed significantly elevated suicide risk, particularly on measures of suicidal thoughts, compared to people who had used ketamine in the past but stopped.¹²

The researchers pointed out that this finding contrasts with the clinical literature and likely reflects key differences in who is being studied. Clinical trials frequently exclude people with substance use disorders, which limits how well their results generalize to chronic recreational users. People who use ketamine outside medical settings tend to have higher baseline rates of depression, trauma, and other substance use, all of which independently raise suicide risk. So the drug that temporarily quiets suicidal thinking in a controlled infusion suite may be part of a pattern that worsens suicide risk in uncontrolled, self-directed use. Any death statistics that only count acute toxicological overdoses will miss suicides in which ketamine played a contributing role through impaired judgment, worsened mental health, or both.

Forensic Challenges in Counting Ketamine Deaths

One reason it is difficult to pin down exactly how many people die from ketamine is that forensic toxicology faces real obstacles with this drug. Ketamine distributes unevenly through the body after death. In case reports, large differences have been found between ketamine concentrations in heart blood and blood drawn from the leg, suggesting that the drug may redistribute between tissues postmortem or that it had not finished distributing before death occurred.¹³ This makes it hard for medical examiners to determine whether the blood level at the time of death was actually lethal, survivable, or incidental.

There is also no universally agreed-upon “lethal concentration” for ketamine the way there is a rough consensus for many opioids. The drug has a wide therapeutic index, meaning the gap between a dose that produces effects and a dose that kills is relatively large. That is precisely what makes it useful in medicine, but it also complicates death investigations. A coroner finding ketamine in a decedent’s blood has to weigh whether the level was high enough to have caused death, whether other drugs were also present, and whether the death might have been environmental rather than pharmacological. Many jurisdictions do not routinely test for ketamine unless there is a specific reason to suspect it, so some deaths may never be attributed to it at all.

Global Patterns and Where Ketamine Use Is Highest

Ketamine use and its harms are not evenly distributed around the world. The estimated prevalence of nonmedical ketamine use in the United States still appears to be lower than in the United Kingdom, Australia, and China. Ketamine seizures have been increasing across the European Union, with particularly large volumes intercepted in the Netherlands and Spain. In parts of Southeast Asia, ketamine ranks among the most commonly used psychoactive drugs, and it is a leading substance of choice in both China and Taiwan.¹

Population size matters when interpreting prevalence percentages. China’s population is more than four times that of the United States, so even if the percentage of users were similar, the absolute number of people affected and potentially at risk of harm would be substantially larger. This helps explain why much of the published clinical literature on chronic ketamine bladder and other long-term harms comes from East Asian research teams: they are seeing more patients with these conditions.

Ketamine Analogues and Emerging Risks

The illicit drug market does not stand still, and ketamine analogues have begun to appear in some regions. One such compound, known as 2-oxo-PCE, triggered a cluster of 56 acute poisonings over a two-month period. Common symptoms included impaired consciousness, confusion, abnormal behavior, high blood pressure, and rapid heart rate. Seizures occurred in about one in six cases. While all patients in that cluster recovered, three required intensive care.¹⁴ Analogues are concerning because users may not know what they are actually taking, standard drug tests may not detect them, and their potency and side-effect profiles can differ from ketamine itself in unpredictable ways. As ketamine becomes more popular recreationally, the market for cheaper or more potent substitutes is likely to grow, potentially adding deaths that never show up in ketamine-specific surveillance.

People who use ketamine bought from informal sources have no reliable way to verify what is in the powder or liquid they receive. Adulterants, substitutions, and unpredictable potency all add layers of danger on top of ketamine’s own risks. This is a familiar problem from the opioid crisis, and while the scale of ketamine adulteration is nowhere near as severe, the dynamic is the same: an unregulated supply chain means the user is always gambling on content and dose.

1
PubMed Central. Trends in nonmedical ketamine use, poisonings, related deaths, pharmaceutical diversions, and law enforcement seizures: results from annual population-based repeated cross-sectional studies
2
PubMed. Overdoses and deaths related to the use of ketamine and its analogues: a systematic review
3
PubMed Central. Recreational ketamine-related deaths notified to the National Programme on Substance Abuse Deaths, England, 1997-2019
4
PubMed. Using cluster analysis to investigate consumption patterns in cases positive to ketamine: a national 7-year study
5
PubMed Central. Ketamine plus Alcohol: What We Know and What We Can Expect about This
6
PubMed Central. Basic metabolic and vascular effects of ketamine and its interaction with fentanyl
7
Journal of Affective Disorders. A systematic review of the incidence of medical serious adverse events in sub-anesthetic ketamine treatment of psychiatric disorders
8
PubMed Central. Association between ketamine use and mortality in critically ill patients receiving mechanical ventilation: Analysis of the MIMIC-IV database
9
Annals of Emergency Medicine. Out-of-Hospital Ketamine: Indications for Use, Patient Outcomes, and Associated Mortality
10
PubMed Central. CYP2B6*6 allele and age substantially reduce steady-state ketamine clearance in chronic pain patients: impact on adverse effects
11
PubMed Central. Multiorgan dysfunction related to chronic ketamine abuse
12
PubMed Central. Ketamine use and differential risk of suicidality among adults in Taiwan
13
PubMed. Postmortem blood ketamine distribution in two fatalities
14
Forensic Science International. Cluster of acute poisonings associated with an emerging ketamine analogue, 2-oxo-PCE