Using poisons information service data to assess the acute harms associated with novel psychoactive substances

The synthetic cannabinoids menace: a review of health risks and toxicity

Synthetic cannabinoids (SCs) are chemically classified as psychoactive substances that target the endocannabinoid system in many body organs. SCs can initiate pathophysiological changes in many tissues which can be severe enough to damage the normal functionality of our body systems. The majority of SCs-related side effects are mediated by activating Cannabinoid Receptor 1 (CB1R) and Cannabinoid Receptor 2 (CB2R). The activation of these receptors can enkindle many downstream signalling pathways, including oxidative stress, inflammation, and apoptosis that ultimately can produce deleterious changes in many organs. Besides activating the cannabinoid receptors, SCs can act on non-cannabinoid targets, such as the orphan G protein receptors GPR55 and GPR18, the Peroxisome Proliferator-activated Receptors (PPARs), and the Transient receptor potential vanilloid 1 (TRPV1), which are broadly expressed in the brain and the heart and their activation mediates many pharmacological effects of SCs. In this review, we shed light on the multisystem complications found in SCs abusers, particularly discussing their neurologic, cardiovascular, renal, and hepatic effects, as well as highlighting the mechanisms that intermediate SCs-related pharmacological and toxicological consequences to provide comprehensive understanding of their short and long-term systemic effects.

Trends in hospital presentations following analytically confirmed synthetic cannabinoid receptor agonist exposure before and after implementation of the 2016 UK Psychoactive Substances Act

BACKGROUND AND AIMS

The United Kingdom (UK) Psychoactive Substances Act (PSA), implemented on the 26^th  May 2016, made the production, supply and sale of all non-exempted psychoactive substances illegal. The aim of this study was to measure trends in hospital presentations for severe toxicity following analytically confirmed synthetic cannabinoid receptor agonist (SCRA) exposure before and after implementation of the PSA.

DESIGN

Observational study.

SETTING

Thirty-four hospitals across the UK participating in the Identification of Novel Psychoactive Substances (IONA) study.

PARTICIPANTS

A total of 627 (79.9% male) consenting individuals who presented to participating hospitals between July 2015 and December 2019 with severe acute toxicity and suspected novel psychoactive substances exposure.

MEASUREMENTS

Toxicological analyses of patient samples were conducted using liquid-chromatography tandem mass-spectrometry. Time-series analysis was conducted on the monthly number of patients with and without analytically confirmed SCRA exposure using Poisson segmented regression.

FINDINGS

SCRAs were detected in 35.7% (n = 224) of patients. After adjusting for seasonality and the number of active sites, models showed no clear evidence of an upward or downward trend in the number of SCRA exposure cases in the period before (incidence rate ratio [IRR], 1.12; 95% CI, 0.99-1.26; P = 0.068) or after (IRR, 0.97; 95% CI, 0.94-1.01; P = 0.202) the implementation of the PSA. There was also no clear evidence of an upward or downward trend in non-SCRA exposure cases before (IRR, 1.12; 95% CI, 0.98-1.27; P = 0.105) or after (IRR, 1.01; 95% CI, 0.98-1.04; P = 0.478) implementation of the PSA.

CONCLUSIONS

There is no clear evidence of an upward or downward trend in the number of patients presenting to UK hospitals with severe acute toxicity following analytically confirmed synthetic cannabinoid receptor agonist exposure since the implementation of the Psychoactive Substances Act.

Adulteration of low-THC products with synthetic cannabinoids: Results from drug checking services

Since late 2019, low‐delta‐9‐tetrahydrocannabinol (THC) preparations adulterated with synthetic cannabinoids (SCs) have been frequently observed in Switzerland. The unawareness of users concerning the presence of SCs and the typically higher potency and toxicity of SCs, when compared with THC, can result in increased health risks. In Switzerland, low‐THC (<1%) cannabis products, except hashish, are legal. These products can act as carrier materials for SCs. In this study, cannabis samples and user self‐reports received through three drug checking services were collected and analysed, to gain deeper insight into this new phenomenon. Samples were collected from January 2020 to July 2021. Liquid chromatography coupled with high‐resolution mass spectrometry was used for the qualitative screening and semi‐quantification of SCs, while gas chromatography with flame ionization detector was applied for the quantification of THC and cannabidiol levels. Reported adverse effects were compared between users who consumed adulterated (SC‐group) and non‐adulterated (THC‐group) products. Of a total 94 samples, 50% contained up to three different SCs. MDMB‐4en‐PINACA was most often detected. All adulterated cannabis flowers contained ≤1% THC. Adulterated hashish also typically presented low THC‐levels (median: 0.8%). The SC‐group was associated with higher numbers of adverse events (p = 0.041). Furthermore, psychologic (p = 0.0007) and cardiologic (p = 0.020) adverse effects were more profound in the SC‐group than in the THC‐group. Drug checking services enabled the timely detection and monitoring of new and potentially dangerous trends. Furthermore, due to user‐reports, additional valuable information was gained on adverse events associated with the consumption of novel SCs.

New psychoactive substances in Eurasia: a qualitative study of people who use drugs and harm reduction services in six countries

Background

This study examines the use of new psychoactive substances (NPS) and the harm reduction response in six Eurasian countries: Belarus, Moldova, Serbia, Kazakhstan, Kyrgyzstan, and Georgia. The aim is to identify current patterns of NPS use and related harms in each country through recording the perspectives and lived experience of people who use drugs and people who provide harm reduction services in order to inform the harm reduction response.

Methodology

The study involved desk-based research and semi-structured interviews/focus groups with 124 people who use drugs and 55 health and harm reduction service providers across the six countries.

Results

People who use drugs in all countries were aware of NPS, primarily synthetic cathinones and synthetic cannabinoids. NPS users generally reflected two groups: those with no prior history of illicit drug use (typically younger people) and those who used NPS on an occasional or regular basis due to the lack of availability of their preferred drug (primarily opiates). In many cases, these respondents reported they would not use NPS if traditional opiates were available. Common factors for choosing NPS included cost and accessibility. Respondents in most countries described NPS markets that use the DarkNet and social media for communication, secretive methods of payment and hidden collection points. A recurring theme was the role of punitive drug policies in driving NPS use and related harms. Respondents in all countries agreed that current harm reduction services were important but needed to be enhanced and expanded in the context of NPS.

Conclusions

The study identified patterns and drivers of NPS use, risk behaviours and drug-related harms. It identified gaps in the current harm reduction response, particularly the needs of non-injectors and overdose response, as well as the harmful effects of punitive drug policies. These findings may inform and improve current harm reduction services to meet the needs of people who use NPS.

Regional, national and international datasets: How they improve our understanding of the acute harms associated with prescription medicine misuse

Prescription medicine misuse is a significant problem in many areas of the world. Understanding the acute and chronic harms related to misuse of prescription medicines allows healthcare professionals, drug addiction treatment services and legislative authorities to determine what interventions may be beneficial to reduce these harms and protect individuals and society. However, it is difficult to obtain systematic data on the harms associated with prescription medicine misuse because of how patient visits to clinics and hospitals are recorded and coded in regional or national databases. In this review, we discuss how regional, national and international sources of information can help develop a greater understanding of the prevalence and pattern of acute harms related to prescription medicine misuse using data from ambulance attendances, emergency department presentations and poisons information services.

New psychoactive substances in Australia: patterns and characteristics of use, adverse effects, and interventions to reduce harm

PURPOSE OF REVIEW

To summarize the most recent peer-review literature on new psychoactive substances (NPS) within Australia.

RECENT FINDINGS

NPS use among the general Australian population is low, yet more pervasive among specific subpopulations. There is considerable heterogeneity among people who use NPS, however, overall, they are not unique from those who use more established illicit drugs. NPS have been shown to be highly adulterated, used as contaminants, variable in dose, and changeable as to the specific substances available over time. Further, analyses of coroners' cases highlight the importance of consumer understanding of NPS effects, particularly where they differ substantially to their more traditional illicit drug counterparts (e.g., synthetic vs. plant cannabinoids). One study posited that legislative approaches to NPS have been (partially) effective in reducing harms, and there are new systems being established to identify NPS-related health harms.

SUMMARY

There have been few studies recently published on NPS in Australia (n = 17), however, findings mostly align with the international literature with respect to the rapidly changing nature of the NPS market, the use of NPS as adulterants, and associated harms. These themes highlight the need for proactive, novel approaches to rapidly identify, and respond to emerging drugs of concern.

Effect of the UK Psychoactive Substances Act 2016 on episodes of toxicity related to new psychoactive substances as reported to the National Poisons Information Service. A time series analysis

BACKGROUND

There have been recent increases in use of new psychoactive substances (NPS) associated with acute health harms including hospital presentations due to toxicity and increasing numbers of deaths. In response, the UK Government enacted generic legislation on 26th May 2016 (the Psychoactive Substances Act) making it an offence to produce, possess with intent to supply, supply, import or export, or possess within a custodial setting a psychoactive substance. We studied the impact of this Act on monthly frequency of enquiries made by health professionals to the UK National Poisons Information Service (NPIS) about NPS. We also studied five commonly used 'conventional' drugs of misuse that had been controlled prior to January 2009.

METHOD

Anonymised clinical enquiries to the NPIS and accesses to the poisons information database TOXBASE were reviewed retrospectively from January 2009 to December 2018 to ascertain the trends in reported toxicity for NPS, cocaine, heroin, cannabis, amphetamines and MDMA. Data were analysed using interrupted time series analysis with the date of the PSA used as an independent predictor.

RESULTS

Over the period of study there were 3,866 NPIS telephone enquiries and 79,271 TOXBASE user accesses made by UK health professionals concerning NPS. There were increases in monthly TOXBASE accesses (t = 7.408, P < 0.0001) and telephone enquiries (t = 4.74, P < 0.001) over the pre-specified period January 2009 to May 2016. Comparing the period after the PSA with that before, there were significant reductions in TOXBASE accesses (t = -3.327, P < 0.001) and telephone enquiries (t = -6.97, P < 0.001), although reductions started before May 2016. There were no significant changes for the five conventional drugs. There were significant reductions in telephone enquiries (t = -3.418, P < 0.001) and non-significant reductions in TOXBASE accesses (t = -1.713, P = 0.089) for NPS between June 2016 and December 2018. Increases in telephone enquiries for cocaine and reductions TOXBASE accesses for MDMA were also observed over that period.

CONCLUSIONS

There have been significant recent reductions in NPIS enquiry activity relating to NPS; although these began before enactment of the PSA in May 2016.

Serotonin Syndrome: Pathophysiology, Clinical Features, Management, and Potential Future Directions

Serotonin syndrome (SS) (also referred to as serotonin toxicity) is a potentially life-threatening drug-induced toxidrome associated with increased serotonergic activity in both the peripheral (PNS) and central nervous systems (CNS). It is characterised by a dose-relevant spectrum of clinical findings related to the level of free serotonin (5-hydroxytryptamine [5-HT]), or 5-HT receptor activation (predominantly the 5-HT_1A and 5-HT_2A subtypes), which include neuromuscular abnormalities, autonomic hyperactivity, and mental state changes. Severe SS is only usually precipitated by the simultaneous initiation of 2 or more serotonergic drugs, but the syndrome can also occur after the initiation of a single serotonergic drug in a susceptible individual, the addition of a second or third agent to long-standing doses of a maintenance serotonergic drug, or after an overdose. The combination of a monoamine oxidase inhibitor (MAOI), in particular MAO-A inhibitors that preferentially inhibit the metabolism of 5-HT, with serotonergic drugs is especially dangerous, and may lead to the most severe form of the syndrome, and occasionally death. This review describes our current understanding of the pathophysiology, clinical presentation and management of SS, and summarises some of the drugs and interactions that may precipitate the condition. We also discuss the newer novel psychoactive substances (NPSs), a growing public health concern due to their increased availability and use, and their potential risk to evoke the syndrome. Finally, we discuss whether the inhibition of tryptophan hydroxylase (TPH), in particular the neuronal isoform (TPH2), may provide an opportunity to pharmacologically target central 5-HT synthesis, and so develop new treatments for severe, life-threatening SS.

Review of the many faces of synthetic cannabinoid toxicities

Introduction

Synthetic cannabinoids (SCs) are psychoactive substances that are gaining popularity for their availability and lack of detection by standardized drug tests. Although some users may perceive SCs as safer alternatives to marijuana, some SCs are more potent and result in more severe toxicities.

Methods

A search of the literature was conducted in the PubMed and SciFinder databases. Results in PubMed were limited to human studies, and only articles in English were included.

Results

Review of the literature illustrates the hazards associated with SC use. A range of severe toxicities affecting numerous systems has been identified, such as arrhythmias, myocardial infarction, sudden cardiac death, psychosis, suicidal ideation, seizures, acute tubular necrosis, and intracranial hemorrhage. Additionally, a recent outbreak of coagulopathies and at least 4 associated deaths due to SCs tainted with brodifacoum have been reported.

Discussion

Synthetic cannabinoids may be perceived as a safer alternative to marijuana; however, SCs can be more potent at the cannabinoid receptors and in turn have greater toxicities. Limited information is available on the metabolism of SCs; however, cytochrome P450 pathways may be involved, which could result in drug interactions and unpredicted adverse effects. Toxicity with SC use is not just related to its effects, but also to additives that may taint these products and enhance their effects. Health care providers should be aware of the range of toxicities related to SC use, and tainted products such as these agents are not detected on routine drug screens.

Patterns of Acute Toxicity Associated with New Psychoactive Substances

This chapter begins by considering why it is important to understand the clinical patterns of acute toxicity associated with new psychoactive substances (NPS), the challenges associated with gathering these data, the sources of information available and the limitations of each. It describes the data triangulation approach that can be used to combine individual, each inherently limited, data sources to help build the picture of the pattern of acute non-fatal toxicity associated with NPS. The chapter illustrates the data triangulation approach by the use of clinical examples and aims to consider mechanism of action data in conjunction with clinical features to provide an overarching understanding of the clinical presentation. Examples of the most important individual and groups of NPS were identified using multimodal literature searching based on the most relevant terms. The chapter provides descriptive accounts that are a complete reference source on the patterns of acute toxicity.

Stereoselective Differences between the Reinforcing and Motivational Effects of Cathinone-Derived 4-Methylmethcathinone (Mephedrone) In Self-Administering Rats

Mephedrone (4-methylmethcathinone (4-MMC)) (MEPH) is a new psychoactive substance (NPS) of the synthetic cathinone class. MEPH has a chiral center and exists as two enantiomers (R-,S-MEPH), yet stereospecific effects of MEPH have not been extensively investigated in preclinical assays. Because significant behavioral and neurochemical differences can exist between enantiomers, probing effects of stereochemistry on biological activity enables separation of adverse and therapeutic effects. Our prior work showed that R-MEPH, relative to S-MEPH, produced greater locomotor activation, place preference, and facilitation of brain reward thresholds in rodents. The present study sought to determine if MEPH enantiomers display stereospecific reward and reinforcement in rat self-administration assays. In Experiment 1, rats were trained to self-administer racemic MEPH (0.50 mg/kg/inf), and dose substitution effects of R-MEPH (0.50 mg/kg/inf) and S-MEPH (0.25, 0.50, 2.00 mg/kg/inf) were examined. In Experiment 2, separate rats were trained to self-administer R-MEPH (0.25, 0.50, 2.00 mg/kg/inf) or S-MEPH (0.25, 0.50, 2.00 mg/kg/inf) and were thereafter evaluated under progressive-ratio access conditions. Within this cohort, 50 kHz ultrasonic vocalizations (USVs) were recorded to measure potential differences in subjective positive affect associated with MEPH enantiomer self-administration. We identified enantiomer- and dose-dependent effects on infusions earned during self-administration following acquisition of racemic MEPH, with greatest infusions under low-effort, fixed-ratio 1 access conditions from low-dose S-MEPH self-administration. When taxed with progressive-ratio access conditions, rats trained to self-administer R-MEPH showed higher break points than those of rats trained to self-administer S-MEPH. Additionally, R-MEPH elicited greatest rates of 50 kHz USVs compared to S-MEPH. Taken together, these data suggest that the R-enantiomer of MEPH is primarily responsible for the rewarding, reinforcing, and motivational properties of racemic MEPH, which increases our understanding of stereospecific preferences pertaining to MEPH abuse.

The Novel Psychoactive Substances in the UK Project: empirical and conceptual review work to produce research recommendations

Background

Although illegal drug use has largely been declining in the UK over the past decade, this period has witnessed the emergence of a range of novel psychoactive substances (NPS) (‘legal highs’). These are new, mostly synthetic, substances that mimic the effects of existing drugs). Despite there being many causes for concern in relation to NPS, there has been little prior study of the burden associated with their use in public health terms. Clarity is lacking on research priorities in this rapidly developing literature.

Objectives

To inform the development of public health intervention research on NPS by reviewing existing data on their use, associated problems and potential responses to such problems.

Design

A scoping review and narrative synthesis of selected bodies of evidence was undertaken to summarise and evaluate what is known about NPS use and the related harms of, and responses to, such use. Relevant literature was identified from electronic databases (covering January 2006 to June 2016 inclusive), Google (Google Inc., Mountain View, CA, USA), relevant websites and online drug forums and by contacting experts. Articles were included if they were primary studies, secondary studies involving the analysis and interpretation of primary research or discussion papers. A conceptual framework postulating an evidence-informed public health approach to NPS use in the UK was developed through a pragmatic literature review, the iterative development of concepts and finalisation in light of the results from the empirical review work. The process also involved feedback from various stakeholders. Research recommendations were developed from both strands of work.

Results

A total of 995 articles were included in the scoping review, the majority of which related to individual-level health-related adverse effects attributable to NPS use. The prevalence of lifetime NPS use varied widely between (e.g. with higher prevalence in young males) and within population subgroups. The most commonly reported adverse effects were psychiatric/other neurological, cardiovascular, renal and gastrointestinal manifestations, and there is limited evidence available on responses. In these and other respects, available evidence is at an early stage of development. Initial evidence challenges the view that NPS should be treated differently from other illicit drugs. The conceptual framework indicated that much of the evidence that would be useful to inform public health responses does not yet exist. We propose a systems-based prevention approach that develops existing responses, is multilevel and life course informed in character, and emphasises commonalities between NPS and other legal and illegal drug use. We make 20 recommendations for research, including nine key recommendations.

Limitations

Scoping reviews do not interrogate evidence in depth, and the disjunction between the scoping review and the conceptual framework findings is worthy of careful attention.

Conclusions

Key research recommendations build on those that have previously been made and offer more evidence-based justification and detail, as previous recommendations have not yet been acted on. The case for decision-making on commissioning new research based on these recommendations is both strong and urgent.

Future work

The validity of recommendations generated through this project could be enhanced via further work with research commissioners, policy-makers, researchers and the public.

Study registration

The systematic review element of this study is registered as PROSPERO CRD42016026415.

Funding

The National Institute for Health Research Public Health Research programme.

Clinical Pharmacology of the Synthetic Cathinone Mephedrone

4-Methyl-N-methylcathinone (mephedrone) is a popular new psychoactive substance (NPS) that is structurally related to the parent compound cathinone, the β-keto analogue of amphetamine. Mephedrone appeared on the street drug market as a substitute for 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) and was subsequently banned due to the potential health risks associated with its use. Nevertheless, mephedrone continues to be widely consumed among specific populations, with unique patterns of misuse. To date, most information about the biological effects of mephedrone comes from user experiences, epidemiological data, clinical cases, toxicological findings, and animal studies, whilst there are very few data regarding its human pharmacodynamics and pharmacokinetics. This chapter reviews the available published data on patterns of mephedrone use, its acute and chronic effects, and its pharmacokinetic properties. More human research is needed to elucidate the safety, toxicity, and addiction potential of mephedrone and related NPS.

Oral fluid drug analysis in the age of new psychoactive substances

Oral fluid has become an important matrix for drugs of abuse analysis. These days the applicability is challenged by the fact that an increasing number of new psychoactive drugs are coming on the market. Synthetic cannabinoids and synthetic cathinones have been the main drug classes, but the diversity is increasing and other drugs like piperazines, phenethylamines, tryptamines, designer opioids and designer benzodiazepines are becoming more prevalent. Many of the substances are very potent, and low doses ingested will lead to low concentrations in biological media, including oral fluid. This review will highlight the phenomenon of new psychoactive substances and review methods for oral fluid drug testing analysis using on-site tests, immunoassays and chromatographic methods.

Deaths of individuals aged 16-24 years in the UK after using mephedrone

OBJECTIVE

Mephedrone is a stimulant drug chemically related to amphetamine, with effects similar to those of amphetamine and cocaine. This study aims to analyse fatalities following ingestion of mephedrone in the UK amongst 16- to 24-year-olds in 2009-2013, providing an update on data presented at the 2nd International Conference on Novel Psychoactive Substances.

METHODS

A literature search was undertaken to identify published information on pharmacology, toxicity and fatalities associated with mephedrone. Fatalities involving mephedrone were extracted from the National Programme on Substance Abuse Deaths database, which receives information on drug-related deaths from coroners in the UK and Islands and other data suppliers. Selection criteria are as follows: deceased aged 16-24 years at time of death and mephedrone directly implicated in the cause of death and/or mentioned in the coroner's verdict.

RESULTS

Thirty cases met the study criteria, and when known, all were of White ethnicity, most (85%) had a history of drug use and 73% were male. Two-thirds (63%) were accidental poisonings. Mephedrone was used with other substances in most cases (87%); other substances were implicated in 60% of deaths.

CONCLUSIONS

Mephedrone use can have potentially fatal consequences, especially in combination with other substances. Deaths from its use in the 16-24 years' age group continue to occur in the UK, despite it being a controlled drug. Health professionals and potential consumers should be alert to this risk.

A novel psychoactive substance poses a new challenge in the management of paranoid schizophrenia

Novel psychoactive substances (NPS), or 'legal highs' are becoming more commonly used as recreational substances in the UK. Their clinical effects are little known and vary considerably between substances. This case discusses a psychiatric inpatient who repeatedly used a stimulant NPS called 'el blanco' while on leave, precipitating relapses of his schizophrenia. The patient initially denied drug use, considering legal highs as different from drugs. The relationship between NPS use and mental state was eventually revealed on careful direct questioning. He recovered and was discharged following treatment with clozapine and education about NPS use. We suggest that specific questioning about NPS usage is added to routine psychiatric history taking and that patients using NPS should be educated about the substances' use.

Synthetic cathinones: a new public health problem

New psychoactive substances (NPS) have completely modified the drug scene and the current landscape of addiction. Synthetic substances, such as substituted or synthetic cathinones, also known as « legal highs », are often produced and used to mimic the effects of controlled drugs such as cocaine, methylenedioxymethamphetamine (MDMA, ecstasy), and methamphetamine. The overwhelming majority of synthetic cathinones are produced in China and South East Asian countries. The Internet has emerged as the new marketplace for NPS, playing a major role in providing information on acquisition, synthesis, extraction, identification, and substance use. All these compounds are intentionally mislabeled and sold on-line under slang terms such as bath salts, plant food, plant feeders and research chemicals. They are sometimes labeled « not for human use » or « not tested for hazards or toxicity ». The rapid spread of NPS forces member countries of the European Union to adapt their response to the potential new dangers that may cause. To date, not only health actors but also the general public need to be clearly informed and aware of dangers resulting from NPS spread and use. Here, we review the major clinical effects of synthetic cathinones to highlight their impact on public health. A literature search was conducted from 2009 to 2014 based on PubMed, Google Scholar, Erowid, and governmental websites, using the following keywords alone or in combination: "new psychoactive substances", "synthetic cathinones", "substituted cathinones", "mephedrone", "methylone", "MDPV", "4-MEC", "addiction", and "substance use disorder".