Retrospective screening of new psychoactive substances (NPS) in post mortem samples from 2014 to 2021

Systematic retrospective processing of previously analysed biological samples has been proven to be a valuable tool in the search for new drugs (e.g. new psychoactive substances (NPS)) and for quality assessment in clinical and forensic toxicology. In a previous study, we developed a strategy for retrospective data-analysis using a personalized library of synthetic cannabinoids, designer benzodiazepines and synthetic opioids obtained from the crowdsourced database HighResNPS (https://highresnps.com). In this study, the same strategy was employed for the compounds within the groups of NPS that were not previously included such as synthetic cathinones, phenethylamines, aminoindanes, arylalkylamines, piperazine derivates, piperidines, pyrrolidines, indolalkylamines and arylcyclohexylamines. Synthetic opioids and designer benzodiazepines, which were not part of the previous study, were also included. To enhance the effectiveness of the retrospective analysis, a predicted retention time was included for all entries. Data files from the analysis of 2186 forensic post mortem samples with an Agilent Technologies 6540 ultra-high pressure liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) performed in the laboratory from January 2014 to December 2021 were retrospectively processed with the up-to-date library. Tentative findings were classified in two groups: The findings where MS/MS data was acquired for library match (category 1) and the less certain findings where such data lacked (category 2). Five compounds of category 1 (three synthetic cathinones and two indolalkylamines) were identified in 12 samples. Only one of the findings, 4-MEAPP (4-methyl-α-ethylaminopentiophenone), was deemed plausible after reviewing case information. As many as 501 presumably positive category 2 findings were detected. Using the predicted retention time as an additional criterion the number was significantly reduced but still too high for a manual review. This work has demonstrated that the strategy developed in the previous study can be applied to other NPS groups. However, it is important to note the limitations such a method may have in detecting compounds at very low concentrations.

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.

Can the Intake of a Synthetic Tryptamine be Detected Only by Blood Plasma Analysis? A Clinical Toxicology Case Involving 4-HO-MET

Tryptamines represent a group of hallucinogenic new psychoactive substances with increasing prevalence. Unfortunately, only limited data concerning their toxicology and bioanalysis is available as tryptamines are not included in routine screening procedures in many laboratories. In order to expand the current knowledge, we report a non-fatal clinical toxicology case involving the synthetic tryptamine 4-HO-MET (4-hydroxy-N-methyl-N-ethyl-tryptamine, 3-{2-[ethyl(methyl)amino]ethyl}-1H-indol-4-ol, metocin, or methylcybin). Only blood was available and our systematic blood plasma screening approaches based on gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC) coupled to low-resolution linear ion trap mass spectrometry (ITMSn) or high-resolution tandem mass spectrometry (HRMS/MS) were conducted. The ingestion of the synthetic tryptamine 4-HO-MET could be revealed by blood plasma analysis using both LC-based systematic screening approaches, but not using GC-MS. Furthermore, the detection of metabolites, which may be used to confirm an intake of the parent compound 4-HO-MET, was only successful using LC-HRMS/MS most probably due to its increased sensitivity compared to LC-ITMSn. A total of four metabolites were detected in blood including N-demethyl-, oxo-, and hydroxy-4-HO-MET, as well as the N-oxide. Finally, LC-HRMS/MS analysis revealed a plasma concentration of 193 ng/mL for 4-HO-MET using the standard addition method. The presented data may help clinical and forensic toxicologists with the interpretation of future cases involving synthetic tryptamines, especially if only blood samples are available.

Discriminative Stimulus Effects of Substituted Tryptamines in Rats

Novel synthetic compounds have been available for decades as quasi-legal alternatives to controlled substances. The hallucinogen-like effects of eight novel substituted tryptamines were evaluated to determine their potential abuse liability. Male Sprague-Dawley rats were trained to discriminate 2,5-dimethoxy-4-methylamphetamine (DOM, 0.5 mg/kg, i.p., 30 min) from saline. 4-Acetoxy-N,N-diethyltryptamine (4-AcO-DET), 4-hydroxy-N-methyl-N-ethyltryptamine (4-OH-MET), 4-hydroxy-N,N-diethyltryptamine (4-OH-DET), 4-acetoxy-N-methyl-N-isopropyltryptamine (4-AcO-MiPT), 4-acetoxy-N,N-dimethyltryptamine (4-AcO-DMT), 4-hydroxy-N,N-dimethyltryptamine (4-OH-DMT, psilocin), 5-methoxy-N-methyl-N-isopropyltryptamine (5-MeO-MiPT), 4-acetoxy-N,N-diisopropyltryptamine (4-AcO-DiPT), and 4-hydroxy-N,N-diisopropyltryptamine (4-OH-DiPT) were tested for their ability to substitute for the discriminative stimulus effects of DOM. All test compounds fully substituted for DOM with potencies less than or equal to that of DOM. 4-OH-MET, 4-OH-DET, 4-OH-DMT, and 4-AcO-DMT decreased response rate at doses that fully substituted. Because the test compounds produced DOM-like discriminative stimulus effects, they may have similar abuse liability as DOM. 4-Acetoxy substituted compounds were less potent than 4-hydroxy substituted compounds, and the N,N-diisopropyl compounds were less potent than the dimethyl, diethyl, N-methyl-N-ethyl, and N-methyl-N-isopropyl compounds.

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.

4-MeO-PCP and 3-MeO-PCMo, new dissociative drugs, produce rewarding and reinforcing effects through activation of mesolimbic dopamine pathway and alteration of accumbal CREB, deltaFosB, and BDNF levels

RATIONALE

A high number of synthetic dissociative drugs continue to be available through online stores, leading to their misuse. Recent inclusions in this category are 4-MeO-PCP and 3-MeO-PCMo, analogs of phencyclidine. Although the dissociative effects of these drugs and their recreational use have been reported, no studies have investigated their abuse potential.

OBJECTIVES

To examine their rewarding and reinforcing effects and explore the mechanistic correlations.

METHODS

We used conditioned place preference (CPP), self-administration, and locomotor sensitization tests to assess the rewarding and reinforcing effects of the drugs. We explored their mechanism of action by pretreating dopamine receptor (DR) D1 antagonist SCH23390 and DRD2 antagonist haloperidol during CPP test and investigated the effects of 4-MeO-PCP and 3-MeO-PCMo on dopamine-related proteins in the ventral tegmental area and nucleus accumbens. We also measured the levels of dopamine, phosphorylated cyclic-AMP response element-binding (p-CREB) protein, deltaFosB, and brain-derived neurotrophic factor (BDNF) in the nucleus accumbens. Additionally, we examined the effects of both drugs on brain wave activity using electroencephalography.

RESULTS

While both 4-MeO-PCP and 3-MeO-PCMo induced CPP and self-administration, only 4-MeO-PCP elicited locomotor sensitization. SCH23390 and haloperidol inhibited the acquisition of drug CPP. 4-MeO-PCP and 3-MeO-PCMo altered the levels of tyrosine hydroxylase, DRD1, DRD2, and dopamine, as well as that of p-CREB, deltaFosB, and BDNF. All drugs increased the delta and gamma wave activity, whereas pretreatment with SCH23390 and haloperidol inhibited it.

CONCLUSION

Our results indicate that 4-MeO-PCP and 3-MeO-PCMo induce rewarding and reinforcing effects that are probably mediated by the mesolimbic dopamine system, suggesting an abuse liability in humans.

Prevalence and epidemiological associates of novel psychedelic use in the United States adult population

BACKGROUND

Novel psychedelics approximate classic psychedelics, but unlike classic psychedelics, novel psychedelics have been used by humans for a shorter period of time, with fewer data available on these substances.

AIMS

The purpose of this study was to determine the prevalence of novel psychedelic use and the associations of novel psychedelic use with mental health outcomes.

METHODS

We estimated the prevalence of self-reported, write-in lifetime novel psychedelic use and evaluated the associations of novel psychedelic use with psychosocial characteristics, past month psychological distress, and past year suicidality among adult respondents pooled from years 2008-2016 of the National Survey on Drug Use and Health (weighted n=234,914,788).

RESULTS

A fraction (weighted n=273,720; 0.12%) reported lifetime novel psychedelic use. This cohort tended to be younger, male, and White, have greater educational attainment but less income, be more likely to have never been married, engage in self-reported risky behavior, and report lifetime illicit use of other drugs, particularly classic psychedelics (96.9%). (2-(4-Bromo-2,5-dimethoxyphenyl)ethanamine) (2C-B) (30.01%), (2,5-dimethoxy-4-iodophenethylamine) (2C-I) (23.9%), and (1-(2,5-dimethoxy-4-ethylphenyl)-2-aminoethane) (2C-E) (14.8%) accounted for the majority of lifetime novel psychedelic use. Although lifetime novel psychedelic use was not associated with psychological distress or suicidality compared to no lifetime novel psychedelic use or classic psychedelic use, relative to lifetime use of classic psychedelics but not novel psychedelics, lifetime novel psychedelic use was associated with a greater likelihood of past year suicidal thinking (adjusted Odds Ratio (aOR)=1.4 (1.1-1.9)) and past year suicidal planning (aOR=1.6 (1.1-2.4)).

CONCLUSION

Novel psychedelics may differ from classic psychedelics in meaningful ways, though additional, directed research is needed.

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.

Death cases involving certain new psychoactive substances: A review of the literature

In the last decades, more and more new psychoactive substances (NPS) were introduced on the drug market which were sold as "legal" alternatives for classic drugs and misused medications. Due to an increased number of available substances and a growing utilization by users of common drugs but also by inexperienced users because of the supposed "legal" status, also undesired adverse effects of these NPS, at worst leading to death, became apparent. This review summarizes fatalities previously described in scientific literature which were attributed to the use of NPS or such cases, in which intake of NPS was proven or even assumed to contribute to death. This summary includes an overview of substances involved (particularly synthetic cannabinoids ("spice"), novel opioids and synthetic cathinones ("bath salts")) as well as of postmortem concentrations determined in various biological matrices. The compiled data assist forensic toxicologists with the interpretation of death cases involving NPS.

Population Survey Data Informing the Therapeutic Potential of Classic and Novel Phenethylamine, Tryptamine, and Lysergamide Psychedelics

INTRODUCTION

The majority of contemporary psychedelic research has focused on ayahuasca, lysergic acid diethylamide, and psilocybin, though there are hundreds of novel psychedelic compounds that may have clinical utility. The purpose of the present study was to evaluate the therapeutic potential of classic and novel phenethylamine, tryptamine, and lysergamide psychedelics via a large, nationally representative population-based survey.

METHODS

We tested the unique associations of lifetime classic and novel phenethylamine, tryptamine, and lysergamide psychedelics with past month psychological distress and past year suicidality among respondents pooled from years 2008-2017 of the National Survey on Drug Use and Health (weighted N = 260,964,827).

RESULTS

Lifetime classic tryptamine use was associated with a decreased odds of past month psychological distress [aOR = 0.76; (0.69-0.83)] and past year suicidal thinking [aOR = 0.79; (0.72-0.87)]. Lifetime novel phenethylamine use, on the other hand, was associated with an increased odds of past year suicidal thinking [aOR = 1.44; (1.06-1.95)] and past year suicidal planning [aOR = 1.60; (1.06-2.41)]. No other significant associations were found.

DISCUSSION AND CONCLUSIONS

These findings, which may be driven by differences in pharmacodynamics, suggest that classic tryptamines may hold the greatest therapeutic potential of the psychedelics, whereas novel phenethylamines may pose risk for harm. The present findings thus support continued research on the clinical application of classic tryptamines. Though the current results caution against the clinical utility of novel phenethylamines, further study of these and other novel psychedelic substances is nonetheless warranted to better understand their potential application.

Fatality Following Ingestion of Tetrahydrofuranylfentanyl, U-49900 and Methoxy-Phencyclidine

Novel psychoactive substances (NPS), and specifically novel opioids, continue to cause adverse events, including death, within drug-using populations. As the number of opioid-related overdoses continues to increase, laboratories have identified the emergence of new fentanyl analogues and other synthetic opioid-related drugs. Tetrahydrofuranylfentanyl (THFF) has been identified in Europe and the United States as an emerging novel opioid, causing death in at least 15 drug-using individuals to date. THFF is structurally similar to furanylfentanyl, a previously characterized novel opioid responsible for numerous adverse events, including death. In this case report, THFF, U-49900 and methoxy-phencyclidine were identified in postmortem blood and urine specimens collected after a suspected overdose. As part of the death investigation, an unknown substance was collected from the scene and analytically confirmed as THFF and U-49900. To further assist laboratories in identifying THFF ingestion, metabolic profiling was conducted using pooled human liver microsomes. Characterized metabolites were then confirmed in the specimens collected during this investigation. In total, seven metabolites were identified for THFF, most notably THF-norfentanyl and hydroxyl-THFF. THF-norfentanyl provides utility as a biomarker because it is a unique metabolite of THFF. 4-Anilino-N-phenethylpiperidine (4-ANPP) and its metabolite, hydroxyl-4-ANPP, were identified in microsomal incubations and collected specimens, but usefulness as biomarkers is limited due to commonality between other fentanyl analogues and co-ingestion as a synthesis precursor. To our knowledge, this case report is the first to document a fatality after ingestion of THFF and U-49900 in the United States.

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.