Phencyclidine analog use in Sweden—intoxication cases involving 3-MeO-PCP and 4-MeO-PCP from the STRIDA project

3-Methoxy-Phencyclidine Induced Psychotic Disorder: A Literature Review and an 18F-FDG PET/CT Case Report

New Psychoactive Substances (NPS) are modifying the drug scenario worldwide and have become a public health concern because of their toxicological profiles and their harmful physical/psychological effects. 3-Methoxy-Phencyclidine (3-MeO-PCP), a non-competitive antagonist of glutamate N-methyl-D-aspartate (NMDA) receptors, belongs to the phencyclidine-like subfamily of arylcyclohexylamines and has gained attention for its toxic, sometimes fatal, effects. Despite several cases of intoxication and death reported in the literature, little is known about substance-induced psychotic disorders (SIP) and potential cognitive impairment following 3-MeO-PCP intake. This literature review aimed to summarize available evidence about 3-MeO-PCP mechanisms of action and physical and psychotropic effects and to spread preliminary findings about persistent psychotic symptoms and impaired cognitive functioning. Additionally, the case of an SIP is reported in a 29-year-old man with small oral intakes of 3-MeO-PCP over two weeks until a high dose ingestion. Psychometric and neuropsychological assessment and brain [18F]-fluorodeoxyglucose positron emission tomography integrated with computed tomography were used to support clinical description. Identifying and addressing the characteristic clinical features and neural substrates of NPS-induced psychoses might help clinicians with a more precise differentiation from other psychotic disorders. Although further studies are required, phenotyping the cognitive profile of NPS users might provide targets for tailored therapeutic approaches.

Metabolism of four novel structural analogs of ketamine, 2-FXE [2-(ethylamino)-2-(2-fluorophenyl) cyclohexan-1-one], 2-MDCK [2-(methylamino)-2-(o-tolyl) cyclohexan-1-one], 3-DMXE [2-(ethylamino)-2-(m-tolyl) cyclohexan-1-one], and 2-DMXE [2-(ethylamino)-2-(o-tolyl) cyclohexan-1-one], in human liver microsomes based on ultra-performance liquid chromatography-high-resolution tandem mass spectrometry

New psychoactive substances are constantly emerging, among which ketamine analogs with the core structure of 2-amino-2-phenylcyclohexanone have attracted global attention due to their continued involvement in acute intoxications. The monitoring of these substances largely relies on the acquisition of metabolic data. However, the lack of in vitro human metabolism information for these emerging structural analogs presents significant challenges to drug control efforts. To address this challenge, we investigated the first-phase metabolism patterns of four novel ketamine structural analogs of 2-FXE [2-(ethylamino)-2-(2-fluorophenyl) cyclohexan-1-one], 2-MDCK [2-(methylamino)-2-(o-tolyl) cyclohexan-1-one], 3-DMXE [2-(ethylamino)-2-(m-tolyl) cyclohexan-1-one], and 2-DMXE [2-(ethylamino)-2-(o-tolyl) cyclohexan-1-one] utilizing human liver microsomes for the first time. Metabolites were identified using ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry. Our findings reveal that N-dealkylation and hydroxylation are the primary metabolic reactions, alongside other notable reactions, including oxidation, reduction, and dehydration. Based on our extensive research, we propose N-dealkylation and hydroxylation metabolites as appropriate analytical markers for monitoring the consumption of these substances.

Hair-based rapid UPLC-MS/MS analysis of 36 phencyclidine-type substances in forensic cases

Phencyclidine (PCP) is a frequently abused dissociative agent. It causes confusion, increased tendencies toward violence, and concentration-dependent cytotoxicity after entry into the body. The parent nucleus of phencyclidine-type substances is arylcyclohexylamine, which is easy to modify; therefore, abusers and dealers can readily synthesize substitutes beyond the drug control catalog. An urgent need exists to establish screening methods for phencyclidine-type substances to provide technical support for abuse monitoring. In this study, 20 mg of hair was pulverized in 500 mL of methanol containing 0.5 ng/mL PCP-d5. After ultrasonication, centrifugation, and filtration, the supernatant was analyzed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) operating in the multiple reaction monitoring mode. Phencyclidine-type substances were separated in 13 min on a biphenyl column using a mobile phase gradient composed of A (water, formic acid 0.1%, acetonitrile 5%, 20 mmol/L ammonium acetate) and B (acetonitrile). The developed and validated method showed good selectivity, sensitivity (limit of detection: 0.25-2 pg/mg and lower limit of quantitation: 0.5-4 pg/mg), linearity (R2 > 0.994), accuracy, and precision (< 20%), and a dilution effect. The method also showed good recovery and acceptable matrix effects for most of the targeted compounds. This analytical approach was successfully applied for the identification and quantification of phencyclidine-type substances in hair from 87 authentic forensic cases. Nine analytes were detected: ketamine (10.3-26211.3 pg/mg), 2-F-2-oxo-PCE (11.5-4034.9 pg/mg), 2-FDCK (14.0-43290.2 pg/mg), 2-BrDCK (10.6-21170.0 pg/mg), nor2-FDCK (10.1-16767.4 pg/mg), tiletamine (10.1-3250.8 pg/mg), O-PCE (43.3-166.1 pg/mg), DCK (10.2-90.4 pg/mg), and norDCK (24.9-103.0 pg/mg).

No prescription? No problem: A qualitative study investigating self-medication with novel psychoactive substances (NPS)

BACKGROUND

The proliferation of Novel Psychoactive Substances (NPS) presents a challenge for global drug policy. The ease of online drug purchase and the emergence of the dark web have created new avenues for the growth of NPS. Despite the global nature of this issue, limited research has examined motivations of use. These include perceived safety or convenience, an interest in novel pharmacology and self-exploration. Recent evidence has suggested individuals may be self-medicating with NPS, however this phenomenon has yet to be thoroughly explored. This study aims to investigate the occurrence of NPS self-medication, identify the specific NPS involved, and understand the motivations behind their use.

METHODS

Discussions surrounding self-medication using NPS were collected between October 2022 and February 2023 via a content analysis of a Reddit community. Ninety-three threads, comprising 182,490 words and 5023 comments, were collected and cleaned. A frequency analysis was conducted to identify the NPS discussed, and data was analysed systematically through the process of iterative categorization (IC).

RESULTS

Our study revealed frequent discussions about the self-medication with several NPS, notably etizolam, clonazolam, diclazepam, flualprazolam, 2-FMA, 4F-MPH, 3-FPM and 3-MeO-PCP. Individuals were mainly self-treating ADHD, anxiety and depression. Motivations for choosing NPS included access, cost, legality and a dissatisfaction with conventional healthcare. Substances were often chosen based on a profile of "Functionality" and outcomes varied. The use of clonazolam was highlighted as particularly problematic.

CONCLUSION

The current study provides insight into the phenomenon of self-medication with NPS within an internet demographic, exploring the motivations behind why individuals choose NPS for a variety of disorders. The easy access to NPS and lack of scientific data pose a significant challenge for drug policy. Future policies should focus on improving healthcare providers knowledge of NPS use, removing barriers to adult ADHD diagnosis and rebuilding trust between individuals and addiction services.

Arylcyclohexylamine Derivatives: Pharmacokinetic, Pharmacodynamic, Clinical and Forensic Aspects

Since the 2000s, an increasing number of new psychoactive substances (NPS) have appeared on the drug market. Arylcyclohexylamine (ACH) compounds such as ketamine, phencyclidine and eticyclidine derivatives are of particular concern, given their rapidly increasing use and the absence of detailed toxicity data. First used mainly for their pharmacological properties in anesthesia, their recreational use is increasing. ACH derivatives have an antagonistic activity against the N-methyl-D-aspartate receptor, which leads to dissociative effects (dissociation of body and mind). Synthetic ketamine derivatives produced in Asia are now arriving in Europe, where most are not listed as narcotics and are, thus, legal. These structural derivatives have pharmacokinetic and pharmacodynamic properties that are sometimes very different from ketamine. Here, we describe the pharmacology, epidemiology, chemistry and metabolism of ACH derivatives, and we review the case reports on intoxication.

Overdoses and deaths related to the use of ketamine and its analogues: a systematic review

Background: Although the misuse of ketamine constitutes a worldwide issue, ketamine is quickly taking its place as a therapeutic option in the management of several mental disorders. However, the use of ketamine and/or its analogues, as well as combinations with other drugs, can be fatal.Objective: To outline the cases of overdoses and deaths related to the use of ketamine and/or its analogues, as reported in the scientific literature. To investigate if ketamine is safe in a therapeutic context, particularly in its use as an antidepressant.Methods: Electronic searches were performed on three medical databases. Articles describing cases of overdose and/or death associated with ketamine and/or its analogues were included. After the removal of duplicates, title analysis and full-text analysis, 34 articles were included in this review.Results: Eighteen articles described fatal cases and sixteen described overdoses. Poly-substance use was mentioned in 53% of the selected articles. Most cases were males and the ages varied from two to 65 years old. A total of 312 overdose cases and 138 deaths were reported. In both death reports and overdose cases, ketamine was preponderant: 89.1% and 79%, respectively. No cases of overdose or death related to the use of ketamine as an antidepressant in a therapeutic setting were found; most of the deaths occurred in the circumstances of polydrug use and overdoses left no sequelae.Conclusion: There is legitimate concern about the risks involving the use of ketamine and its analogues, especially in recreational settings. On the other hand, ketamine as medicine is considered safe and it is listed as an essential medicine by the World Health Organization. Although clinicians must remain vigilant, this should not deter appropriate prescription.

Reports of Adverse Events Associated with Use of Novel Psychoactive Substances, 2017-2020: A Review

An important role of modern forensic and clinical toxicologists is to monitor the adverse events of novel psychoactive substances (NPS). Following a prior review from 2013 to 2016, this critical literature review analyzes and evaluates published case reports for NPS from January 2017 through December 2020. The primary objective of this study is to assist in the assessment and interpretation of these cases as well as provide references for confirmation methods. Chemistry, pharmacology, adverse events and user profiles (e.g., polypharmacy) for NPS are provided including case history, clinical symptoms, autopsy findings and analytical results. Literature reviews were performed in PubMed and Google Scholar for publications using search terms such as NPS specific names, general terms (e.g., 'designer drugs' and 'novel psychoactive substances'), drug classes (e.g., 'designer stimulants') and outcome-based terms (e.g., 'overdose' and 'death'). Government and website drug surveillance databases and abstracts published by professional forensic science organizations were also searched. Toxicological data and detailed case information were extracted, tabulated, analyzed and organized by drug category. Case reports included overdose fatalities (378 cases), clinical treatment and hospitalization (771 cases) and driving under the influence of drugs (170 cases) for a total of 1,319 cases providing details of adverse events associated with NPS. Confirmed adverse events with associated toxidromes of more than 60 NPS were reported including synthetic cannabinoid, NPS stimulant, NPS hallucinogen, NPS benzodiazepine and NPS opioid cases. Fifty of these NPS were reported for the first time in January 2017 through December 2020 as compared to the previous 4 years surveyed. This study provides insight and context of case findings described in the literature and in digital government surveillance databases and websites during a recent 4-year period. This review will increase the awareness of adverse events associated with NPS use to better characterize international emerging drug threats.

The First Fatal Intoxication with 3-MeO-PCP in the UK and a Review of the Literature

The phencyclidine derivative 3-Methoxyphencyclidine (3-MeO-PCP) is a potent dissociative hallucinogen. Sought for recreational use as a novel psychoactive substance, it can also induce acute psychological agitation and pathophysiological cardiorespiratory effects. Due to the harms associated with its use, 3-MeO-PCP was added to the 'Green List' of materials covered by the 1971 Convention on Psychotropic Substances as a Schedule II substance by the United Nations Commission on Narcotic Drugs in April 2021. There have been 15 previous reports of fatal intoxications following 3-MeO-PCP use, but only one was attributable to 3-MeO-PCP intoxication alone. In this report we detail the first fatality due to 3-MeO-PCP intoxication to be reported in the UK, along with a review of the surrounding literature. Whilst the blood concentrations associated with 3-MeO-PCP toxicity and fatality remain unclear, by providing details of sample collection and storage conditions this case will aid in future interpretations. Furthermore, this case suggests that 3-MeO-PCP toxicity may be exacerbated by exercise. Users of 3-MeO-PCP should be cautioned against its use as a 'club drug' or in a similar setting where elevations in heart rate, body temperature and blood pressure may occur.

Determination of 3-MeO-PCP in human blood and urine in a fatal intoxication case, with a specific focus on metabolites identification

3-Methoxyphencyclidine (3-MeO-PCP) is a new psychoactive substance that belongs to the phencyclidines family, first identified in Europe in 2012. This drug presents a stronger binding to N-methyl-D-aspartate (NMDA) receptors when compared to phencyclidine, which results in more potent effects, even at low concentrations. Very few articles have been published regarding 3-MeO-PCP in forensic toxicology. In this paper, the authors present a fatal 3-MeO-PCP intoxication case. In addition to the detection of the parent drug, metabolites were investigated in urine and, for the first time in the scientific literature, in blood. 3-MeO-PCP and its metabolites were quantitated by liquid chromatography-tandem mass spectrometry system (LC-MS/MS). Identification was confirmed by liquid chromatography-high resolution mass spectrometry (LC-HRMS). 3-MeO-PCP tested positive in femoral blood (3 525 ng/mL) and urine (7 384 ng/mL). The femoral blood concentration was higher than the fatal concentrations range already reported in the literature (from 50 to 3 200 ng/mL). 3-MeO-PCP metabolites, including O-demethyl-3-MeO-PCP, piperidine-OH-3-MeO-PCP, O-demethyl-piperidine-di-OH-3-MeO-PCP and piperidine-di-OH-3-MeO-PCP, were detected in blood. In addition, two new metabolites, O-demethyl-piperidine-OH-3-MeO-PCP and O-demethyl-cyclohexyl-OH, were identified in both blood and urine. Unfortunately, due to the lack of reference material on the market, it was not possible to measure the concentration of these metabolites. However, the ratios between the metabolites and the parent drug were useful to estimate their analytical response and prevalence. At this time, considering the low ratios (<1) between metabolites and parent drug, metabolites testing does not seem useful to increase the detection window of the drug.

Analysis of Google Trends to monitor new psychoactive substance. Is there an added value?

The past decade has seen an increase in the development and availability of a broad category of drugs, known as new psychoactive substances (NPS). NPS are challenging for public health authorities, therefore the two major drug monitoring bodies - the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and the United Nations Office on Drugs and Crime (UNODC) - have implemented the EU Early Warning System (EWS) and Early Warning Advisory (EWA), respectively. While these monitoring systems are informative, it is difficult to keep up with the constant and rapid developmental rate of NPS. The EMCDDA has recognised the need for an alternative and technologically derived early warning system. The aim of this research is to determine whether Google Trends and drug discussion forum data can be used to complement early warning systems for NPS. Forty-eight substances were used in this study and classed into groups based on their chemical structure, following the UNODC classification system. Google Trends data (time range: 2004-2019) and drug forum data (time range: 2003-2018) were extracted for each substance and visual trend profiles were created for class groups as well as individual substances. Analysis was conducted to determine when a substance first appeared on Google Trends and a drug discussion forum as well as their trends over time. This date of first appearance was then compared to the date the substance was first reported to UNODC. Of the three data sources utilised, substances were most likely to appear on Google Trends first. Amongst the different classes of NPS, discernible trends ('block', 'successive', and 'generational' trends) were observed. These trends reflect the evolution of the manufacture of substances or generations of substances that has been observed in the literature. For example, in the synthetic cannabinoids' category, a generational trend is observed that corresponds to the different generations of synthetic cannabinoids. When comparing Google Trends and Drugs-Forum directly, the order of appearance and duration of presence for substances aligns accurately for most classes. Google Trends showed the emergence, persistence, or transient nature of substances, which could direct the focus of law enforcement, health organisation and laboratory resources towards a limited number of substances. When one considers the reliance of individual information seeking on the Web as well as the prominence of NPS on the Web, it becomes clear that Google Trends and drug discussion forums could be used as a complement to current early warning systems.

Methoxphenidine (MXP) induced abnormalities: Addictive and schizophrenia-related behaviours based on an imbalance of neurochemicals in the brain

BACKGROUND AND PURPOSE

Methoxphenidine is a dissociative-based novel psychoactive designer drug. Although fatal accidents from methoxphenidine abuse have been reported, recreational use of the drug continues. We aim to provide scientific supportfor legal regulation of recreational abuse of methoxphenidine by demonstrating its the pharmacological action.

EXPERIMENTAL APPROACH

Addictive potential of methoxphenidine was examined using intravenous self-administration test with rats and conditioned place preference test with mice. Further, a series of behavioural tests (open field test, elevated plus maze test, novel object recognition test, social interaction test and tail suspension test) performed to assess whether methoxphenidine caused schizophrenia-related symptoms in mice. Additionally, neurotransmitter enzyme-linked immunosorbent assay and western blot were used to confirm methoxphenidine-induced neurochemical changes in specific brain regions related to abnormal behaviours.

KEY RESULTS

Methoxphenidine caused addictive behaviours via reinforcing and rewarding effects. Consistently, methoxphenidine induced over-activation of dopamine pathways in the nuclear accumbens, indicating activation of the brain reward circuit. Also, methoxphenidine caused all categories of schizophrenia-related symptoms, including positive symptoms (hyperactivity, impulsivity), negative symptoms (anxiety, social withdrawal, depression) and cognitive impairment. Consistently, methoxphenidine led to the disruption of the hippocampal-prefrontal cortex pathway that is considered to be pathological involved in schizophrenia.

CONCLUSIONS AND IMPLICATIONS

We demonastrate that methoxphenidine causes addictive and schizophrenia-like behaviours and induces neurochemical changes in brain regions associated with these behaviours. We propose that methoxphenidine could be used in developing useful animal disease models and that it also requires legal restrictions on its recreational use.

Presence of the ketamine analog of 2-fluorodeschloroketamine residues in wastewater

Ketamine (KET) analogs are increasingly emerging as new psychoactive substances (NPS). The present report describes the first detection of the KET analog, 2-fluorodeschloroketamine (2F-DCK), in influent samples collected from nine wastewater treatment plants in seven major Chinese cities from 2018 to 2020 by wastewater-based epidemiology (WBE). An analytical method based on solid-phase extraction and subsequent gas chromatography-mass spectrometry was developed for the detection of 2F-DCK and KET. The stability experiments showed that 2F-DCK and KET remained stable in wastewater for 15 days at room and frozen temperatures, and at two pH values (pH = 7 and pH = 2), with residue amounts between 90% and 110%. KET was detected in all samples, whereas 2F-DCK was detected in only four samples: from Guangzhou in 2018, Shenzhen in 2019, and Quanzhou and Nanning in 2020, indicating that 2F-DCK has been used as early as 2018 in China. The renal clearance of 2F-DCK was predicted based on the quantitative structure-pharmacokinetic relationship model, which was used to calculate an excretion factor of 3.7. The 2F-DCK consumption in four cities ranged from 3.71 ± 0.05 to 55 ± 0.09 mg/day/1000 inh, and KET ranged from 1.3 ± 0.04 to 76.5 ± 4.63 mg/day/1000 inh. This is the first study to investigate 2F-DCK by WBE, which provides relevant real-time data on the growth of NPS use, as well as useful information for the government to develop new policies.

Drugs of abuse and ocular effects

Illicit drugs and substances of abuse are increasingly used by adults and teenagers, with novel substances constantly becoming available. Many substances can cause ocular effects or visually threatening conditions. Current literature informing eye-care practitioners on these effects is scant. The present scoping review reports the ocular effects of most commonly used drugs and substances of abuse in the teenage and adult populations of North America. Ovid MEDLINE and Ovid EMBASE databases were searched for publications from 1980 to 2019 regarding ocular effects of drug use. The selected papers regarded human subjects, in either teenage or adult population and included all types of studies, including case reports. Publications in English or in French were included. Exclusion criteria were publications about the use of prescriptions drugs, drug withdrawal, and publications about the use of alcohol, tobacco, or cannabis. Some 241 papers were retained and analysed. The use of various drugs and substances can lead to damage to structures throughout the eye, including but not limited to corneal conditions, glaucoma and other optic neuropathies, maculopathies and endophthalmitis. The data presented in this review may help guide clinicians in their diagnosis and treatment of certain ocular conditions, which could otherwise not be linked to drug use.

Analytical Characterization of 3-MeO-PCP and 3-MMC in Seized Products and Biosamples: The Role of LC-HRAM-Orbitrap-MS and Solid Deposition GC-FTIR

Among the phencyclidine (PCP) and synthetic cathinone analogs present on the street market, 3-methoxyphencyclidine (3-MeO-PCP) is one of the most popular dissociative hallucinogen drugs, while 3-methylmethcathinone (3-MMC) is a commonly encountered psychostimulant. Numerous 3-MeO-PCP- and 3-MMC-related intoxication cases have been reported worldwide. Identification of the positional isomers of MeO-PCP and MMC families are particularly challenging for clinical and forensic laboratories; this is mostly due to their difficult chromatographic separation (particularly when using liquid chromatography–LC) and similar mass spectrometric behaviors. 3-MeO-PCP and 3-MMC were identified in two powders, detained by two subjects and seized by the police, by different analytical techniques, including liquid chromatography-high-resolution accurate-mass Orbitrap mass spectrometry (LC-HRAM-Orbitrap-MS), and solid deposition gas chromatography-Fourier transform infrared spectroscopy (sd-GC-FTIR). LC-HRAM-Orbitrap-MS allowed us to assign the elemental formulae C₁₈H₂₇NO (MeO-PCP) and C₁₁H₁₅NO (MMC) through accurate mass measurement of the two MH⁺ ions, and the comparison of experimental and calculated MH⁺ isotopic patterns. However, MH⁺ collision-induced product ions spectra were not conclusive in discriminating between the positional isomers [(3-MeO-PCP vs. 4-MeO-PCP) and (3-MMC vs. 4-MMC and 2-MMC)]. Likewise, sd-GC-FTIR easily allowed us to differentiate between the MeO-PCP and MMC positional isomers unambiguously, confirming the presence of 3-MeO-PCP and 3-MMC, due to the high-quality match factor of the experimental FTIR spectra against the target FTIR spectra of MeO-PCP and MMC isomers in a dedicated library. 3-MeO-PCP (in contrast to 3-MMC) was also detected in blood and urine samples of both subjects and analyzed in the context of routine forensic casework by LC-HRAM-Orbitrap-MS following a simple deproteinization step. In addition, this untargeted approach allowed us to detect dozens of phase I and phase II 3-MeO-PCP metabolites in all biological specimens. Analysis of the extracted samples by sd-GC-FTIR revealed the presence of 3-MeO-PCP, thus confirming the intake of such specific methoxy-PCP isomer in both cases. These results highlight the effectiveness of LC-HRAM-Orbitrap-MS and sd-GC-FTIR data in attaining full structural characterization of the psychoactive drugs, even in absence of reference standards, in both non-biological and biological specimens.

In vitro and in vivo metabolism and detection of 3-HO-PCP, a synthetic phencyclidine, in human samples and pooled human hepatocytes using high resolution mass spectrometry

The new psychoactive substance (NPS) 3-HO-PCP, a phencyclidine (PCP) analog, was detected in a law enforcement seizure and in forensic samples in Denmark. Compared with PCP, 3-HO-PCP is known to be a more potent dissociative NPS, but no toxicokinetic investigations of 3-HO-PCP are yet available. Therefore, 3-HO-PCP was quantified in in vivo samples, and the following were investigated: plasma protein binding, in vitro and in vivo metabolites, and metabolic targets. All samples were separated by liquid chromatography and analyzed by mass spectrometry. The unbound fraction in plasma was determined as 0.72 ± 0.09. After in vitro incubation with pooled human hepatocytes, four metabolites were identified: a piperidine-hydroxyl-and piperidine ring opened N-dealkyl-COOH metabolite, and O-glucuronidated- and O-sulfate-conjugated metabolites. In vivo, depending on the sample and sample preparation, fewer metabolites were detected, as the O-sulfate-conjugated metabolite was not detected. The N-dealkylated-COOH metabolite was the main metabolite in the deconjugated urine sample. in vivo analytical targets in blood and brain samples were 3-HO-PCP and the O-glucuronidated metabolite, with 3-HO-PCP having the highest relative signal intensity. The drug levels of 3-HO-PCP quantified in blood were 0.013 and 0.095 mg/kg in a living and a deceased subject, respectively. The 3-HO-PCP concentrations in deconjugated urine in a sample from a living subject and in post-mortem brain were 7.8 and 0.16 mg/kg, respectively. The post mortem results showed a 1.5-fold higher concentration of 3-HO-PCP in the brain tissue than in the post mortem blood sample.

Emergence of new psychoactive substance 2-fluorodeschloroketamine: Toxicology and urinary analysis in a cluster of patients exposed to ketamine and multiple analogues

New psychoactive substances (NPS) emerge continually, amongst which is a growing class of ketamine analogues with an arylcyclohexylamine backbone. Recently we reported a poisoning outbreak associated with 2-oxo-PCE (deschloro-N-ethyl-ketamine). The present report describes the emergence of another ketamine analogue, 2-fluorodeschloroketamine (2F-DCK). The compound was first detected in a patient's urine, its identity confirmed by accurate mass analysis and comparison with reference standard. Four putative metabolites were identified, including nor-2F-DCK, dehydronor-2F-DCK (major metabolite) and two hydroxylated derivatives of nor-2F-DCK. Between January and July 2019, 20 cases of analytically confirmed 2F-DCK exposure were encountered. In 19 out of 20 cases, at least one more ketamine-type drug was detected concurrently with 2F-DCK, including ketamine (90%), deschloroketamine (DCK, 50%), 2-oxo-PCE (45%) and tiletamine (10%). In particular, six of the cases showed the presence of 4 ketamine-type drugs in the same urine sample. The clinical effects observed in patients exposed to 2F-DCK are predominantly neurological (impaired consciousness, agitation, abnormal behaviour) and cardiovascular (hypertension, tachycardia); five patients had loss of consciousness or convulsion. Management was mainly supportive; all patients recovered uneventfully. This is the first clinical case series involving 2F-DCK and frontline medical personnel are urged to be aware of this rapidly expanding class of NPS, in particular the co-ingestion of multiple ketamine analogues.

Drug trends and harm related to new psychoactive substances (NPS) in Sweden from 2010 to 2016: Experiences from the STRIDA project

Background

In the past decade, hundreds of new psychoactive substances (NPS) have been introduced as unclassified alternatives to the illicit drugs. The NPS represent a growing health concern by causing adverse effects and deaths but are usually undetectable by conventional drug tests. This report summarizes results and experiences from analytically confirmed drug-related acute intoxications in emergency departments (ED) and intensive care units (ICU) enrolled in the Swedish STRIDA project on NPS in 2010–2016.

Methods and findings

ED/ICU intoxications suspected to involve NPS were enrolled in the project, after initial contact with the Poisons Information Centre (PIC). Serum/plasma and urine samples, and sometimes drug products, were subjected to a comprehensive toxicological investigation, and the PIC retrieved information on associated clinical symptoms and treatment. Between January 2010-February 2016, 2626 cases were enrolled. The patients were aged 8–71 (mean 27, median 24) years and 74% were men. Most biological samples (81%) tested positive for one, or more (70%), psychoactive drugs, including 159 NPS, other novel or uncommon substances, classical recreational and illicit drugs, and prescription medications. When first detected, most NPS or other novel substances (75%) were not banned in Sweden, but they usually disappeared upon classification, which however often took a year or longer. Some NPS were found to be especially harmful and even fatal.

Conclusions

The STRIDA project provided a good overview of the current drug situation in Sweden and demonstrated a widespread use and rapid turnover of many different psychoactive substances. The accomplishment of the project can be attributed to several key factors (close collaboration between the PIC and laboratory to identify suspected poisonings, free analysis, continuous updating of analytical methods, evaluation of adverse effects, and sharing information) that are useful for future activities addressing the NPS problem. The results also illustrated how drug regulations can drive the NPS market.

Designer drugs: mechanism of action and adverse effects

Psychoactive substances with chemical structures or pharmacological profiles that are similar to traditional drugs of abuse continue to emerge on the recreational drug market. Internet vendors may at least temporarily sell these so-called designer drugs without adhering to legal statutes or facing legal consequences. Overall, the mechanism of action and adverse effects of designer drugs are similar to traditional drugs of abuse. Stimulants, such as amphetamines and cathinones, primarily interact with monoamine transporters and mostly induce sympathomimetic adverse effects. Agonism at μ-opioid receptors and γ-aminobutyric acid-A (GABAA) or GABAB receptors mediates the pharmacological effects of sedatives, which may induce cardiorespiratory depression. Dissociative designer drugs primarily act as N-methyl-D-aspartate receptor antagonists and pose similar health risks as the medically approved dissociative anesthetic ketamine. The cannabinoid type 1 (CB1) receptor is thought to drive the psychoactive effects of synthetic cannabinoids, which are associated with a less desirable effect profile and more severe adverse effects compared with cannabis. Serotonergic 5-hydroxytryptamine-2A (5-HT2A) receptors mediate alterations of perception and cognition that are induced by serotonergic psychedelics. Because of their novelty, designer drugs may remain undetected by routine drug screening, thus hampering evaluations of adverse effects. Intoxication reports suggest that several designer drugs are used concurrently, posing a high risk for severe adverse effects and even death.

Neuronal and peripheral damages induced by synthetic psychoactive substances: an update of recent findings from human and animal studies

Preclinical and clinical studies indicate that synthetic psychoactive substances, in addition to having abuse potential, may elicit toxic effects of varying severity at the peripheral and central levels. Nowadays, toxicity induced by synthetic psychoactive substances poses a serious harm for health, since recreational use of these substances is on the rise among young and adult people. The present review summarizes recent findings on the peripheral and central toxicity elicited by “old” and “new” synthetic psychoactive substances in humans and experimental animals, focusing on amphetamine derivatives, hallucinogen and dissociative drugs and synthetic cannabinoids.

Intoxication with 3-MeO-PCP alone: A case report and literature review

RATIONALE

3-Methoxyphencyclidine (3-MeO-PCP) is a new psychoactive substance derived from phencyclidine. Although it can lead to severe intoxications, the main manifestations and optimal management have not been well characterized. Here, we report 2 cases of 3-MeO-PCP intoxication in the same patient, and summarize the manifestations of this intoxication reported in literature.

PATIENT CONCERNS

A 17-year-old male purchased a bag of 3-MeO-PCP on the Internet but took an oral dose (200 mg) that corresponds to the less active isomer 4-MeO-PCP. He developed high blood pressure (158/131 mm Hg), tachycardia (100 bpm), and neurological manifestations (confusion, hypertonia, nystagmus, and then agitation). A maculopapular rash appeared, although this may have been related to the administration of midazolam. Hyperlactatemia (2.6 mmol/L) was the main laboratory finding. Seven days later, he returned to the emergency department after sniffing 50 mg of 3-MeO-PCP. High blood pressure, tachycardia, and neurological manifestations (psychomotor impairment and dysarthria) were present but less severe than after the first intoxication.

DIAGNOSIS

In the first intoxication, the blood and urine 3-MeO-PCP concentrations were, respectively, 71.1 ng/mL and 706.9 ng/mL. Conventional toxicity tests were all negative. In the second intoxication, biological samples were not available.

INTERVENTIONS

In the first intoxication, treatment consisted of intravenous hydration and midazolam. The patient was transferred to an intensive care unit for monitoring. After the second intoxication, he was monitored for 12 hours.

OUTCOMES

The patient's condition improved quickly in both cases.

LESSONS

These cases provide additional information on the manifestations of 3-MeO-PCP intoxication. These manifestations are mainly cardiovascular (high blood pressure, tachycardia) and neurological. The fact that second (50 mg) intoxication was less severe than the first (200 mg) is suggestive of a dose-effect relationship for 3-MeO-PCP. The first case also emphasizes the risk of dosing errors caused by the similarity between the names "3-MeO-PCP" and "4-MeO-PCP."

Epidemiology of NPS Based Confirmed Overdose Cases: The STRIDA Project

The Swedish STRIDA project on new psychoactive substances (NPS) monitored the occurrence and health hazards of novel recreational drugs in Sweden through evaluation of analytically confirmed adverse events presenting in emergency departments and intensive care units. During a ~6-year period from 2010 to early 2016, about 2,600 cases of suspected NPS intoxications were included in the project. About 75% of patients were men and the total age range was 8-71 (median 24) years and 57% were 25 years or younger. A large number of NPS belonging to many different drug classes were identified in project samples of urine and blood (serum/plasma) submitted for free drug testing, including synthetic cannabinoid receptor agonists, stimulants, cathinones, hallucinogens, dissociative drugs, benzodiazepines, and opioids, and also in drug materials from the cases forwarded to the laboratory along with the biological samples. The STRIDA project has been shown to serve as an effective early warning system for NPS by collecting data on incidence, distribution, and adverse effects and has supported healthcare professionals in the knowledge and critical care of intoxications caused by a wide range of novel substances. The results of the STRIDA project have also illustrated how drug regulations can drive the NPS market.

Detectability of Dissociative Psychoactive Substances in Urine by Five Commercial Phencyclidine Immunoassays

Methoxetamine (MXE) and the arylcyclohexylamines 3-methoxy-PCP (3-MeO-PCP) and 4-methoxy-PCP (4-MeO-PCP) are substituted analogs of the dissociative psychoactive substances ketamine and phencyclidine (PCP), respectively. They have emerged on the new psychoactive substances (NPS) market as legal alternatives to these classically banned dissociatives. Little data has been published regarding the cross-reactivity of these NPS in PCP immunoassays (IAs). The aim of this work was to explore the possibilities of detecting 3-MeO-PCP, 4-MeO-PCP, MXE and ketamine in commercial IAs for PCP. The cross-reactivity study was performed in five different PCP IAs using urine-free, spiked samples and urine samples obtained from two 3-MeO-PCP overdose cases. 3-MeO-PCP and 4-MeO-PCP showed cross-reactivity (ranging from 1–143%) in all PCP IAs evaluated. MXE only showed very weak cross-reactivity (ranged from 0.04 to 0.25%) and ketamine was not detected in any PCP IA evaluated. Urine samples from the two overdose cases were positive for PCP in all IAs evaluated. The commercial PCP IAs evaluated exhibited utility as rapid, preliminary screening techniques for 3-MeO-PCP and 4-MeO-PCP, but not for ketamine. The low reactivity of MXE limits its detectability in the PCP IAs evaluated.

Occurrence and time course of NPS benzodiazepines in Sweden - results from intoxication cases in the STRIDA project

CONTEXT

In recent years, many unclassified benzodiazepines (BZD) have appeared through online sale as new psychoactive substances (NPS). This study describes bioanalytical and clinical data related to intoxications involving NPS BZD ("designer BZD") in the Swedish STRIDA project.

STUDY DESIGN

Case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals all over Sweden for emergency treatment in 2012-2016.

PATIENTS AND METHOD

Urine samples collected in the STRIDA project were analyzed for 28 NPS BZD, using immunoassay and liquid chromatography-high-resolution mass spectrometry . Data of patient's age, gender, reported substance exposure, clinical signs, and treatment were obtained from medical and Poisons Information Center (PIC) records.

RESULTS

A total of fifteen different NPS BZD were analytically confirmed in 217 of 1913 (11%) cases involving patients (81% men) aged 15-66 (mean 28) years. The frequency of positive samples increased from 4% in 2012 to 19% in 2015. Etizolam (20 cases) was the first detected NPS BZD (January 2012), and it was followed by metizolam (four cases), estazolam (two), pyrazolam (33), flubromazepam (33), nifoxipam (five), diclazepam (four), meclonazepam (26), bromazepam (one), flubromazolam (92), deschloroetizolam (one), clonazolam (16), 3-hydroxyphenazepam (eight), ketazolam (one), and phenazepam (one). Most cases (89%) also involved other drugs. Use of NPS BZD was rarely (15%) reported during PIC consultation. In 24 patients exposed only to NPS BZD, CNS depression was the most prominent clinical sign, seven were observed in the intensive care unit, and they responded positively to flumazenil treatment.

CONCLUSIONS

An increasing use of NPS BZD in Sweden was detected in acute intoxication cases, sometimes leading to intensive care monitoring and support needs.

Neurological, sensorimotor and cardiorespiratory alterations induced by methoxetamine, ketamine and phencyclidine in mice

Novel psychoactive substances are intoxicating compounds developed to mimic the effects of well-established drugs of abuse. They are not controlled by the United Nations drug convention and pose serious health concerns worldwide. Among them, the dissociative drug methoxetamine (MXE) is structurally similar to ketamine (KET) and phencyclidine (PCP) and was created to purposely mimic the psychotropic effects of its "parent" compounds. Recent animal studies show that MXE is able to stimulate the mesolimbic dopaminergic transmission and to induce KET-like discriminative and rewarding effects. In light of the renewed interest in KET and PCP analogs, we decided to deepen the investigation of MXE-induced effects by a battery of behavioral tests widely used in studies of "safety-pharmacology" for the preclinical characterization of new molecules. To this purpose, the acute effects of MXE on neurological and sensorimotor functions in mice, including visual, acoustic and tactile responses, thermal and mechanical pain, motor activity and acoustic startle reactivity were evaluated in comparisons with KET and PCP to better appreciate its specificity of action. Cardiorespiratory parameters and blood pressure were also monitored in awake and freely moving animals. Acute systemic administrations of MXE, KET and PCP (0.01-30 mg/kg i.p.) differentially alter neurological and sensorimotor functions in mice depending in a dose-dependent manner specific for each parameter examined. MXE and KET (1 and 30 mg/kg i.p.) and PCP (1 and 10 mg/kg i.p.) also affect significantly cardiorespiratory parameters, systolic and diastolic blood pressure in mice.

New Psychoactive Substances 3-Methoxyphencyclidine (3-MeO-PCP) and 3-Methoxyrolicyclidine (3-MeO-PCPy): Metabolic Fate Elucidated with Rat Urine and Human Liver Preparations and their Detectability in Urine by GC-MS, "LC-(High Resolution)-MSn" and "LC-(High Resolution)-MS/MS"

Background:

3-Methoxyphencyclidine (3-MeO-PCP) and 3-methoxyrolicyclidine (3-MeO-PCPy) are two new psychoactive substances (NPS). The aims of the present study were the elucidation of their metabolic fate in rat and pooled human liver microsomes (pHLM) the identification of the cytochrome P450 (CYP) isoenzymes involved and the detectability using standard urine screening approaches (SUSA) after intake of common users’ doses using gas chromatography-mass spectrometry (GC-MS) liquid chromatography-multi-stage mass spectrometry (LC-MSn) and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS)

Methods:

For metabolism studies rat urine samples were treated by solid phase extraction or simple precipitation with or without previous enzymatic conjugate cleavage. After analyses via LC-HR-MSn the phase I and II metabolites were identified

Results:

Both drugs showed multiple aliphatic hydroxylations at the cyclohexyl ring and the heterocyclic ring single aromatic hydroxylation carboxylation after ring opening O-demethylation and glucuronidation. The transferability from rat to human was investigated by pHLM incubations where O-demethylation and hydroxylation were observed. The involvement of the individual CYP enzymes in the initial metabolic steps was investigated after single CYP incubations. For 3-MeO-PCP CYP 2B6 was responsible for aliphatic hydroxylations and CYP 2C19 and CYP 2D6 for O-demethylation. For 3-MeO-PCPy aliphatic hydroxylation was again catalyzed by CYP 2B6 and O-demethylation by CYP 2C9 and CYP 2D6

Conclusions:

As only polymorphically expressed enzymes were involved pharmacogenomic variations might occur but clinical data are needed to confirm the relevance. The detectability studies showed that the authors’ SUSAs were suitable for monitoring the intake of both drugs using the identified metabolites

Evaluating the abuse potential of psychedelic drugs as part of the safety pharmacology assessment for medical use in humans

Psychedelics comprise drugs come from various pharmacological classes including 5-HT_2A agonists, indirect 5-HT agonists, e.g., MDMA, NMDA antagonists and κ-opioid receptor agonists. There is resurgence in developing psychedelics to treat psychiatric disorders with high unmet clinical need. Many, but not all, psychedelics are schedule 1 controlled drugs (CDs), i.e., no approved medical use. For existing psychedelics in development, regulatory approval will require a move from schedule 1 to a CD schedule for drugs with medical use, i.e., schedules 2-5. Although abuse of the psychedelics is well documented, a systematic preclinical and clinical evaluation of the risks they pose in a medical-use setting does not exist. We describe the non-clinical tests required for a regulatory evaluation of abuse/dependence risks, i.e., drug-discrimination, intravenous self-administration and physical dependence liability. A synopsis of the existing data for the various types of psychedelics is provided and we describe our findings with psychedelic drugs in these models. FDA recently issued its guidance on abuse/dependence evaluation of drug-candidates (CDER/FDA, 2017). We critically review the guidance, discuss the impact this document will have on non-clinical abuse/dependence testing, and offer advice on how non-clinical abuse/dependence experiments can be designed to meet not only the expectations of FDA, but also other regulatory agencies. Finally, we offer views on how these non-clinical tests can be refined to provide more meaningful information to aid the assessment of the risks posed by CNS drug-candidates for abuse and physical dependence. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Phencyclidine-Based New Psychoactive Substances

The serendipitous discovery of phencyclidine (PCP) in 1956 sets the stage for significant research efforts that resulted in a plethora of analogs and derivatives designed to explore the biological effects of this class. PCP soon became the prototypical dissociative agent that eventually sneaked through the doors of clinical laboratories and became an established street drug. Estimations suggest that around 14 PCP analogs were identified as "street drugs" in the period between the 1960s and 1990s. Fast forward to the 2000s, and largely facilitated by advancements in electronic forms of communication made possible through the Internet, a variety of new PCP analogs began to attract the attention of communities interested in the collaborative exploration of these substances. Traditionally, as was the case with the first-generation analogs identified in previous decades, the substances explored represented compounds already known in the scientific literature. As the decade of the noughties unfolded, a number of new PCP-derived substances appeared on the scene, which included some analogs that have not been previously recorded in the published literature. The aim of this chapter is to present a brief introductory overview of substances that have materialized as PCP-derived new psychoactive substances (NPS) in recent years and their known pharmacology. Since N-methyl-D-aspartate receptor (NMDAR) antagonism is implicated in mediating the subjective and mind-altering effects of many dissociative drugs, additional data are included from other analogs not presently identified as NPS.

Bioanalytical Methods for New Psychoactive Substances

Bioanalysis of new psychoactive substances (NPS) is very challenging due to the growing number of compounds with new chemical structures found on the drugs of abuse market. Screening, identification, and quantification in biosamples are needed in clinical and forensic toxicology settings, and these procedures are more challenging than the analysis of seized drug material because of extremely low concentrations encountered in biofluids but also due to diverse metabolic alterations of the parent compounds. This article focuses on bioanalytical single- and multi-analyte procedures applicable to a broad variety of NPS in various biomatrices, such as blood, urine, oral fluid, or hair. Sample preparation, instrumentation, detection modes, and data evaluation are discussed as well as corresponding pitfalls. PubMed-listed and English-written original research papers and review articles published online between 01 October 2012 and 30 September 2017 were considered.

When good times go bad: managing 'legal high' complications in the emergency department

Patients can use numerous drugs that exist outside of existing regulatory statutes in order to get "legal highs." Legal psychoactive substances represent a challenge to the emergency medicine physician due to the sheer number of available agents, their multiple toxidromes and presentations, their escaping traditional methods of analysis, and the reluctance of patients to divulge their use of these agents. This paper endeavors to cover a wide variety of "legal highs," or uncontrolled psychoactive substances that may have abuse potential and may result in serious toxicity. These agents include not only some novel psychoactive substances aka "designer drugs," but also a wide variety of over-the-counter medications, herbal supplements, and even a household culinary spice. The care of patients in the emergency department who have used "legal high" substances is challenging. Patients may misunderstand the substance they have been exposed to, there are rarely any readily available laboratory confirmatory tests for these substances, and the exact substances being abused may change on a near-daily basis. This review will attempt to group legal agents into expected toxidromes and discuss associated common clinical manifestations and management. A focus on aggressive symptom-based supportive care as well as management of end-organ dysfunction is the mainstay of treatment for these patients in the emergency department.

Synthetic cannabinoid "Black Mamba" infidelity in patients presenting for emergency stabilization in Colorado: a P SCAN Cohort

BACKGROUND

Use of new psychoactive substances (NPS) has increased over the last decade. During this period, variability of both clinical presentations and chemical compositions of these compounds has increased. Synthetic cannabinoids (SCs) are the most commonly used NPS and there are more than 100 documented unique molecules in this class. "Black Mamba", often associated to ADB-FUBINACA, is the most commonly used SC in Colorado. It has been linked to kidney injury, myocardial toxicity, seizures, and death.

OBJECTIVES

We aim to identify the chemical constituents and quantification of eight cases of reported "Black Mamba" use in order to further understand the clinical variability in patients presenting for emergency stabilization.

METHODS

We report data from eight cases of reported "Black Mamba" use prospectively captured through the Colorado site of the Psychoactive Surveilance Consortium and Analysis Network (P SCAN). P SCAN is a geographically representative group of academic hospitals that capture clinical presentation, outcome, and biologic samples from patients that present for emergency stabilization following NPS use. Serum and urine samples were analyzed and quantified by liquid chromatography-quadrupole time-of-flight mass spectrometry after a qualitative screen for over 600 unique NPS compounds.

RESULTS

In the reported eight cases, the median age was 28 years old. There were four male and four females. Four patients had agitation/delirium and four patients had chest pain. Normal saline, benzodiazepines and ondansetron were the common treatment provided in the emergency department (ED). Two patients were discharged from the ED and six patients being admitted for emergency observation with a median length of stay (LOS) of six hours. No deaths were reported. Confirmatory testing revealed that only five patients (62.5%) had SCs found in blood or urine samples. Cocaine, NRG-3, 3-methoxyphencyclidine hydrochloride (MeO-PCP), and methamfetamine were identified in other presentations.

CONCLUSIONS

The wide range of clinical presentations from "Black Mamba" use may be explained by the wide variability of chemical constituents found by laboratory analysis.

3-MeO-PCP intoxication in two young men: First in vivo detection in Italy

3-MeO-PCP or 3-methoxyphencyclidine is a derivative of phencyclidine. It acts as a dissociative anesthetic and it has allegedly hallucinogenic and sedative effects. There are almost no documented intoxication cases and references about its pharmacology and toxicity in literature. This study presents two concomitant intoxication cases due to consumption of 3-MeO-PCP and alcohol. A 19 (A) and a 21 years old (B) men were brought to Santa Maria Nuova Hospital in a comatose state (Glasgow score 3). They showed respiratory acidosis, right anisocoria with mydriatic pupils and hypothermia. Toxicological screening was negative. They were intubated for 7-8h. Almost 24h after hospitalization they were still in a delirious and agitated status. The subjects declared a high alcohol consumption and ingestion of unknown pills. Blood and urine were collected upon their arrival to the Emergency Department and sent to our Forensic Toxicology Division. Blood alcohol content was 2.0g/L for subject A and 1,7g/L for subject B. The specimens were analyzed by means of GC-MS, revealing the presence of 3-MeO-PCP. A confirmation and quantification was carried out by means of a new and fully validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for new psychoactive substances (NPS) detection. The analysis was performed adding acetonitrile to the samples, the supernatant was dried and reconstituted with methanol. Mephedrone-D3 was used as internal standard. Acquisition was performed through multiple reaction monitoring (MRM) dynamic mode. The MRM transitions used for quantification of 3-MeO-PCP were: m/z 274→86, 121. 3-MeO-PCP was quantified in all the biological samples at the following concentrations: 350.0 (blood) and 6109.2 (urine) ng/mL for A; 180.1 (blood) and 3003.6 (urine) ng/mL for B. Taking into account the analytical results, we can suppose that the manifested symptoms were due to the consumption of 3-MeO-PCP in synergy with alcohol. Our report is the first case of 3-MeO-PCP intoxication in Italy and one of the few documented all over the world. For this reason, this case represents a significant worrisome alarm about the spread of this substance. Here we want to highlight the importance of having an effective and broad-spectrum analytical method in order to face the NPS issue.

New psychoactive substances: an overview on recent publications on their toxicodynamics and toxicokinetics

This review article covers English-written and PubMed-listed review articles and original studies published between January 2015 and April 2016 dealing with the toxicodynamics and toxicokinetics of new psychoactive substances. Compounds covered include stimulants and entactogens, synthetic cannabinoids, tryptamines, NBOMes, phencyclidine-like drugs, benzodiazepines, and opioids. First, an overview and discussion is provided on timely review articles followed by an overview and discussion on recent original studies. Both sections are then concluded by an opinion on these latest developments. This review shows that the NPS market is still highly dynamic and that the data published on their toxicodynamics and toxicokinetics can hardly keep pace with the appearance of new entities. However, data available are very helpful to understand and predict how NPS may behave in severe intoxication. The currently best-documented parameter is the in vitro metabolism of NPS, a prerequisite to allow detection of NPS in biological matrices in cases of acute intoxications or chronic consumption. However, additional data such as their chronic toxicity are still lacking.