Extensive Underreported Exposure to Ketamine Among Electronic Dance Music Party Attendees

Ketamine in neuropsychiatric disorders: an update

The discovery of ketamine as a rapid-acting antidepressant led to a new era in the development of neuropsychiatric therapeutics, one characterized by an antidepressant response that occurred within hours or days rather than weeks or months. Considerable clinical research supports the use of-or further research with-subanesthetic-dose ketamine and its (S)-enantiomer esketamine in multiple neuropsychiatric disorders including depression, bipolar disorder, anxiety spectrum disorders, substance use disorders, and eating disorders, as well as for the management of chronic pain. In addition, ketamine often effectively targets symptom domains associated with multiple disorders, such as anxiety, anhedonia, and suicidal ideation. This manuscript: 1) reviews the literature on the pharmacology and hypothesized mechanisms of subanesthetic-dose ketamine in clinical research; 2) describes similarities and differences in the mechanism of action and antidepressant efficacy between racemic ketamine, its (S) and (R) enantiomers, and its hydroxynorketamine (HNK) metabolite; 3) discusses the day-to-day use of ketamine in the clinical setting; 4) provides an overview of ketamine use in other psychiatric disorders and depression-related comorbidities (e.g., suicidal ideation); and 5) provides insights into the mechanisms of ketamine and therapeutic response gleaned from the study of other novel therapeutics and neuroimaging modalities.

Ketamine, an Old-New Drug: Uses and Abuses

Ketamine as an old-new drug has a variety of clinical implications. In the last 30 years, ketamine has become popular for acute use in humans. Ketamine in standard doses is principally utilized for the induction and maintenance of surgical procedures. Besides its use in anesthesia and analgesia, recent studies have shown that ketamine has found a place in the treatment of asthma, epilepsy, depression, bipolar affective disorders, alcohol and heroin addiction. Ketamine primarily functions as a noncompetitive antagonist targeting the N-methyl-D-aspartate (NMDA) receptor, but its mechanism of action is complex. It is generally regarded as safe, with low doses and short-term use typically not leading to significant adverse effects. Also, ketamine is known as a powerful psychostimulant. During the past decade, ketamine has been one of the commonly abused drugs.

Characteristics of poisonings involving ketamine in the United States, 2019-2021

BACKGROUND

The use of ketamine, a controlled dissociative anesthetic, has become more widespread in recent years with recreational/nonmedical use increasing and ketamine becoming more widely available in clinics to treat depression.

AIMS

We examined recent trends in adverse effects related to ketamine use.

METHODS

US National Poison Control data were examined, focusing on ketamine exposures among those aged ⩾13 between 2019 and 2021 (n = 758). We examined quarterly trends in exposure and delineated correlates of patients experiencing a major adverse effect or death.

RESULTS

The number of reported exposures increased 81.1% from 2019 Quarter 1 through 2021 Quarter 4, from 37 to 67 (p = 0.018). The majority of patients were male (57.1%), and the plurality of cases involved intentional misuse or "abuse" (39.5%), followed by suspected suicide attempt (19.7%) and unintentional exposure (18.9%). A fifth (19.6%) experienced a major adverse effect or death. A third (33.4%) co-used other drugs; the drugs most commonly co-used were benzodiazepines (14.6%), alcohol (10.3%), and opioids (8.7%). Co-use of gamma-hydroxybutyrate (GHB; adjusted prevalence ratio (aPR) = 3.43, 95% confidence interval (CI): 1.57-7.46) and opioids (aPR = 2.44, 95% CI: 1.46-4.08) was associated with increased risk for a major adverse effect or death, as was injection-only administration (aPR = 2.68, 95% CI: 1.21-5.92).

CONCLUSIONS

Although still rare, poisonings involving ketamine have increased in recent years. Polydrug use-particularly with opioids or GHB-appears to be a particular risk factor for more serious adverse effects. As prevalence of use increases, it is important to monitor adverse effects and co-occurring behaviors to inform timely prevention and harm reduction as needed.

Trends in Ketamine Use, Exposures, and Seizures in the United States up to 2019

Objectives. To determine whether there have been shifts in nonmedical ketamine use, poisonings ("exposures"), and seizures. Methods. We used generalized additive models to detect trends in past-year use (2006-2019), exposures (1991-2019), and seizures (2000-2019) involving ketamine in the United States. Results. There was a quarterly increase in self-reported past-year nonmedical ketamine use in 2006 to 2014 (Β = 0.21; P = .030) and an increase in 2015 to 2019 (Β = 0.29; P = .036), reaching a peak of 0.9% in late 2019. The rate of exposures increased from 1991 through 2019 (Β = 0.87; P = .006), and there was an increase to 1.1 exposures per 1 000 000 population in 2014, with rates remaining stable through 2019. The rate of ketamine seizures increased from 2000 through 2019 (Β = 2.27; P < .001), with seizures reaching a peak in 2019 at 3.2 per 1000 seizures. Conclusions. Indicators suggest that ketamine use and availability has increased, including before increased medical indications, but nonmedical use is still currently uncommon despite increased acceptance and media coverage. (Am J Public Health. 2021;111(11):2046-2049. https://doi.org/10.2105/AJPH.2021.306486).

Recreational ketamine-related deaths notified to the National Programme on Substance Abuse Deaths, England, 1997-2019

BACKGROUND

Ketamine is a phencyclidine derivative with dissociative anaesthetic properties. Increasing numbers of individuals in England take ketamine recreationally. Information on deaths arising from such use in England is presented.

METHODS

Cases were extracted on 31 January 2020 from the National Programme on Substance Abuse Deaths database, based on text searches of the cause of death, coroner's verdict and positive toxicology results for the terms 'ketamine' or 'norketamine'.

FINDINGS

During 1997-2005, there were <5 deaths p.a. in which ketamine was implicated. Numbers increased until 2009 (21), plateauing until 2016; thereafter, deaths have risen to about 30 p.a. Decedents' characteristics (N = 283): male 84.1%, mean age 31.2 (SD 10.0) years, employed 56.5%, drug use history 79.6% and living with others 60.3%. Ketamine was detected with other substances in most cases. Main (74.6%) underlying cause of death was accidental poisoning. Ketamine may have impaired judgement in other cases.

CONCLUSIONS

Although controlled, recreational ketamine use and related fatalities continue to increase. Consumers need to be more aware of the potentially fatal risks they face.

Harm related to recreational ketamine use and its relevance for the clinical use of ketamine. A systematic review and comparison study

BACKGROUNDS

Ketamine is a dissociative anesthetic that is currently considered for several new indications.

AIM

To deduce the safety of long-term ketamine treatment using the harm of heavy recreational (non-medical) ketamine use as a proxy for maximal possible harm of ketamine treatment.

METHODS

Systematic literature review according to PRISMA guidelines to identify controlled studies on ketamine-related harm in heavy recreational ketamine users. Results were compared with serious adverse events (SAEs) in patients treated with ketamine according to three systematic reviews considering dosing regimen and cumulative dose.

RESULTS

The systematic search yielded 25 studies. Heavy recreational ketamine use can escalate to ketamine dependency and was often dose-dependently associated with other SAEs, including cognitive and mental disorders, and gastrointestinal and urinary tract symptoms, which disappeared upon marked reduction of ketamine use. Heavy ketamine users have a much higher cumulative exposure to ketamine than ketamine treated patients (>90 times), which may explain why SAEs in the clinical context are mostly mild and reversible and why ketamine dependence was not reported in these patients.

CONCLUSION

Treatment of patients with ketamine is not associated with ketamine dependency or SAEs. However, caution is needed since data on long-term clinical ketamine use with a long-term follow-up is lacking.

Self-Correction of Unreported Marijuana Use by Participants Taking a Street Intercept Survey

Background: Due to underreporting, a major challenge associated with drug use surveys is obtaining precise estimates of drug use. Objective: This study examined reliability of self-reported lifetime marijuana use among electronic dance music (EDM) party attendees - a high-risk population for drug use. Methods: 794 adults (35.1% female) entering EDM parties were intercept-surveyed. Participants were asked about lifetime marijuana use early in the survey. Those not reporting use were asked 5-10 min later if their earlier response was correct. Participants reporting their original response was not correct were asked to check off a reason why they did not originally report use. Participants were also asked at the end of the survey how honestly they responded throughout the survey. Prevalence of lifetime marijuana use with and without corrected responses was compared and risk factors for underreporting were examined using a Poisson generalized linear model. Results: Among those not reporting marijuana use, 31.2% subsequently reported use when asked again. Prevalence of use increased from 73.7% to 81.9% after correcting responses, an 8.2% absolute increase and a 10.0% relative increase. Reporting lifetime use of ecstasy and/or LSD was associated with lower risk for underreporting marijuana use. Compared to those reporting that they answered all questions honestly, those who reportedly answered most or no questions honestly were at higher risk for underreporting. Conclusion: Asking participants to confirm previous responses can help detect underreporting of drug use on intercept surveys. Results can inform survey methods when participants are believed to be at risk for underreporting.