Sympathomimetic toxicity in a case of analytically confirmed recreational use of naphyrone (naphthylpyrovalerone)

Synthetic Cathinones in Belgium: Two Case Reports with Different Outcomes Observed in the Emergency Room

We herein report two cases of cathinone intoxication. The first case is about a drug addict who was admitted to the emergency room after the injection of an unknown compound. He presented with tachycardia, palpitations, mydriasis, dyspnea, dizziness, headache and nausea. After leaving the hospital against medical advice, he returned the next day with police escort, presenting aggressiveness and agitation signs. One month later, he returned one more time for sleeping disorders, hallucinations and anxiety. He was finally transferred for his 21st detoxification treatment. The second case concerns a man who was wandering the streets and tried to escape when police officers called him. He confessed to snorting of N-ethylpentedrone and was admitted with severe agitation including delusion of persecution, tachycardia, mydriasis and fever. Because of renal failure, rhabdomyolysis and metabolic acidosis, he was transferred to the intensive care unit where he manifested worsening of the symptoms, turning into coma. He was intubated for 3 days before a complete resolution of the symptoms. A screening was performed by high-resolution mass spectrometry followed by quantifications made by high-performance liquid chromatography coupled with a diode array detector. In the first case, alpha-pyrrolidinohexiophenone was identified only during the first two admissions. However, as plenty of other psychotropic substances were also found, the cathinone alone could not be held directly responsible for the symptoms. In the second case, more than 2,000 ng/mL of N-ethylpentedrone was found without any decrease in the next 17 h, underlining the long half-life of this compound. Unlike the first case, symptoms could be clearly attributed to the cathinone. In conclusion, cathinones can be found on the Belgian illicit drug market, with various routes of administration and clinical consequences. In these two case reports, some common points were observed initially. However, one patient was finally able to leave the hospital without any treatment, whereas the other would most likely have died without intensive care.

An updated review on synthetic cathinones

Cathinone, the main psychoactive compound found in the plant Catha edulis Forsk. (khat), is a β-keto analogue of amphetamine, sharing not only the phenethylamine structure, but also the amphetamine-like stimulant effects. Synthetic cathinones are derivatives of the naturally occurring cathinone that largely entered the recreational drug market at the end of 2000s. The former "legal status", impressive marketing strategies and their commercial availability, either in the so-called "smartshops" or via the Internet, prompted their large spread, contributing to their increasing popularity in the following years. As their popularity increased, the risks posed for public health became clear, with several reports of intoxications and deaths involving these substances appearing both in the social media and scientific literature. The regulatory measures introduced thereafter to halt these trending drugs of abuse have proved to be of low impact, as a continuous emergence of new non-controlled derivatives keep appearing to replace those prohibited. Users resort to synthetic cathinones due to their psychostimulant properties but are often unaware of the dangers they may incur when using these substances. Therefore, studies aimed at unveiling the pharmacological and toxicological properties of these substances are imperative, as they will provide increased expertise to the clinicians that face this problem on a daily basis. The present work provides a comprehensive review on history and legal status, chemistry, pharmacokinetics, pharmacodynamics, adverse effects and lethality in humans, as well as on the current knowledge of the neurotoxic mechanisms of synthetic cathinones.

Naphyrone (naphthylpyrovalerone): Pharmacokinetics, behavioural effects and thermoregulation in Wistar rats

Naphthylpyrovalerone (naphyrone) is a pyrovalerone cathinone that potently inhibits monoamine transporters and provides stimulatory-entactogenic effects. Little is known about the safety of naphyrone or its effects in vivo, and more research is needed to acquire knowledge about its fundamental effects on physiology and behaviour. Our objective was to investigate naphyrone's pharmacokinetics, acute toxicity, hyperthermic potential and stimulatory and psychotomimetic properties in vivo in male Wistar rats. Pharmacokinetics after 1 mg/kg subcutaneous (sc.) naphyrone were measured over 6 h in serum, the brain, liver and lungs. Rectal temperature (degree Celsius) was measured over 10 h in group-versus individually housed rats after 20 mg/kg sc. In the behavioural experiments, 5, 10 or 20 mg/kg of naphyrone was administered 15 or 60 min prior to testing. Stimulation was assessed in the open field, and sensorimotor processing in a prepulse inhibition (PPI) task. Peak concentrations of naphyrone in serum and tissue were reached at 30 min, with a long-lasting elevation in the brain/serum ratio, consistent with observations of lasting hyperlocomotion in the open field and modest increases in body temperature. Administration of 20 mg/kg transiently enhanced PPI. Naphyrone crosses the blood-brain barrier rapidly and is eliminated slowly, and its long-lasting effects correspond to its pharmacokinetics. No specific signs of acute toxicity were observed; therefore, clinical care and harm-reduction guidance should be in line with that available for other stimulants and cathinones.

The neurobehavioral effects of the designer drug naphyrone - an experimental investigation with pharmacokinetics and concentration/effect relationship in mice

RATIONALE

The recreational use of naphyrone, a potent synthetic cathinone with a pyrovalerone structure, has raised questions about possible deleterious neurobehavioral consequences.

OBJECTIVE

To investigate naphyrone-induced neurobehavioral effects and alterations in brain monoamines using two patterns of abuse, i.e., single and repeated (binge) use.

METHODS

We studied naphyrone dose/induced locomotor activity relationship at 3, 10, 30, and 100 mg/kg in mice. We investigated the effects of single (30 mg/kg; acute injection) versus repeated (30 mg/kg ×3/day for 3 days; binge injection) intraperitoneal naphyrone administration on locomotor activity, anxiety-like behavior, spatial recognition memory, anhedonia, behavioral despair, and social interaction. We measured post-mortem prefrontal cortex levels of monoamines and modeled naphyrone pharmacokinetics and concentration/locomotor effect relationship.

RESULTS

Both naphyrone administration patterns induced time-dependent increases in locomotor activity (p < 0.001 and p < 0.0001, respectively) and social interaction (p < 0.05 and p < 0.001, respectively) but did not alter spatial recognition memory or anhedonia. Acute naphyrone injection induced anxiety-like behavior (p < 0.01) and reduced resignation (p < 0.01) whereas binge administration induced non-anxiety-like behavior (p < 0.05) and did not alter behavioral despair. Both patterns increased the prefrontal cortex dopamine (p < 0.0001) and norepinephrine (p < 0.05 and p < 0.01, respectively) but not serotonin content. Naphyrone pharmacokinetics followed a two-compartment model with an overall elimination half-life of 0.3 h. The naphyrone concentration/locomotor effect relationship was described by an additive E_max model with an EC₅₀ of 672 μg/L.

CONCLUSIONS

Single naphyrone administration increases locomotor activity according to a direct concentration/effect relationship. The neurobehavioral effects after binge differs from those after single administration and are not explained by drug accumulation given the relatively fast elimination.

The Bridge Between Classical and "Synthetic"/Chemical Psychoses: Towards a Clinical, Psychopathological, and Therapeutic Perspective

The critical spread and dissemination of novel psychoactive substances (NPS), particularly among the most vulnerable youngsters, may pose a further concern about the psychotic trajectories related to the intake of new synthetic drugs. The psychopathological pattern of the "new psychoses" appears to be extremely different from the classical presentation. Therefore, clinicians need more data on these new synthetic psychoses and recommendations on how to manage them. The present mini-review aims at deepening both the clinical, psychopathological features of synthetic/chemical NPS-induced psychoses and their therapeutic strategies, according to the different NPS classes implicated, by underlining the main differences with the "classical" psychoses. A comprehensive review was conducted using the PubMed/Medline database by combining the search strategy of free-text terms and exploding a range of MESH headings relating to the topics of novel psychoactive substances and synthetic/chemical psychoses as follows: {(Novel Psychoactive Substances[Title/Abstract]) AND Psychosis[Title/Abstract])} and for each NPS categories as well, focusing on synthetic cannabinoids and cathinones, without time and/or language restrictions. Finally, an overview of the main clinical and psychopathological features between classical versus NPS-induced chemical/synthetic psychoses is provided for clinicians working with dual disorders and addiction psychiatry. Further insight is given here on therapeutic strategies and practical guidelines for managing patients affected with synthetic/chemical NPS-induced psychoses.

Analysis of neurotransmitter levels in addiction-related brain regions during synthetic cathinone self-administration in male Sprague-Dawley rats

RATIONALE

Synthetic cathinones are used as stimulants of abuse. Different stimulants may induce distinct rates of disease progression, yielding neurochemical changes that may vary across brain regions or neurotransmitter systems.

OBJECTIVES

This research sought to behaviorally and chemically differentiate stages of synthetic cathinone abuse through rodent self-administration and measurement of the neurotransmitter profile in multiple brain regions.

METHODS

Male rats were trained to self-administer α-PVP, mephedrone (4MMC), or saline. Half of each drug group stopped self-administering after autoshaping; the other half self-administered for another 21 days. Brain tissue from amygdala, hippocampus, hypothalamus, PFC, striatum, and thalamus was profiled with electrochemical detection to assess neurotransmitter levels.

RESULTS

During autoshaping, the majority of infusions were delivered noncontingently. In the self-administration phase, rats responded more for α-PVP and 4MMC than for saline, demonstrating that both synthetic cathinones were reinforcing. Longer durations of exposure elevated 5-HIAA in hypothalamus, PFC, and hippocampus, indicating that learning may produce changes in addiction-related brain regions. Both synthetic cathinones decreased norepinephrine in hippocampus, while α-PVP decreased glutamate in hippocampus and PFC, and 4MMC decreased glutamate in thalamus. Furthermore, α-PVP increased dopaminergic metabolites in striatum, whereas 4MMC decreased serotonin in the amygdala, hippocampus, and PFC. Interestingly, neither synthetic cathinone affected dopamine levels despite their functional effects on the dopaminergic system.

CONCLUSIONS

In summary, the neurotransmitter changes observed here suggest that synthetic cathinone use likely produces sequential neurochemical changes during the transition from use to abuse. Consequently, treatment need may differ depending on the progression of synthetic cathinone abuse.

Scheduling synthetic cathinone substances under the Controlled Substances Act

BACKGROUND AND RATIONALE

Cathinones are amphetamine analogues that produce stimulant effects with rewarding properties. For many decades, synthetic cathinones have been used in the United States (USA) for abuse purposes, leading to concern about public safety by the federal government. Under the Controlled Substances Act (CSA), the federal government may place drugs with high abuse potential but no currently accepted medical use into Schedule I of the CSA. The process of scheduling an abusable drug involves both the Department of Health and Human Services (HHS), through the Food and Drug Administration (FDA) and the National Institute on Drug Abuse (NIDA), and the Department of Justice, through the Drug Enforcement Administration (DEA).

RESULTS

This paper details how numerous synthetic cathinones were placed under CSA control between 1973 and 2018, with an emphasis on 10 cathinones that were placed into Schedule I in 2017 (butylone, naphyrone, pentylone, pentedrone, 3-fluoro-N-methylcathinone (FMC), 4-FMC, 4-methyl-N-ethylcathinone, 4-methyl-pyrrolidinopropiophenone, alpha-pyrrolidinobutiophenone, and α-pyrrolidinopentiophenone). A summary is provided of the scientific and medical analysis performed by HHS, in the form of an Eight-Factor Analysis (8FA), as prescribed by the CSA. This 8FA was then evaluated and signed by the Assistant Secretary for Health at HHS and transmitted to DEA, which permanently placed the 10 cathinones into Schedule I after public notices were published into the Federal Register.

DISCUSSION AND CONCLUSIONS

Understanding the scientific data, analysis, and complex process utilized by the US federal government in the CSA scheduling of cathinones with abuse potential and no accepted medical use is important for transparency in governmental decision-making.

DARK Classics in Chemical Neuroscience: Cathinone-Derived Psychostimulants

Cathinone is a plant alkaloid found in khat leaves of perennial shrubs grown in East Africa. Similar to cocaine, cathinone elicits psychostimulant effects which are in part attributed to its amphetamine-like structure. Around 2010, home laboratories began altering the parent structure of cathinone to synthesize derivatives with mechanisms of action, potencies, and pharmacokinetics permitting high abuse potential and toxicity. These "synthetic cathinones" include 4-methylmethcathinone (mephedrone), 3,4-methylenedioxypyrovalerone (MDPV), and the empathogenic agent 3,4-methylenedioxymethcathinone (methylone) which collectively gained international popularity following aggressive online marketing as well as availability in various retail outlets. Case reports made clear the health risks associated with these agents and, in 2012, the Drug Enforcement Agency of the United States placed a series of synthetic cathinones on Schedule I under emergency order. Mechanistically, cathinone and synthetic derivatives work by augmenting monoamine transmission through release facilitation and/or presynaptic transport inhibition. Animal studies confirm the rewarding and reinforcing properties of synthetic cathinones by utilizing self-administration, place conditioning, and intracranial self-stimulation assays and additionally show persistent neuropathological features which demonstrate a clear need to better understand this class of drugs. This Review will thus detail (i) historical context of cathinone use and the rise of "dark" synthetic derivatives, (ii) structural features and mechanisms of synthetic cathinones, (iii) behavioral effects observed clinically and in animals under controlled laboratory conditions, and (iv) neurotransmitters and circuits that may be targeted to manage synthetic cathinone abuse in humans.

Toxicokinetics of the Synthetic Cathinone α-Pyrrolidinohexanophenone

Synthetic cathinones inhibit monoamine transporters, such as serotonin, norepinephrine, and dopamine transporters, and act on the central nervous system via increasing synaptic concentrations of monoamines. These compounds, which are highly addictive and potentially poisonous, are new psychoactive substances. In this study, we investigated the toxicokinetics of the synthetic cathinone, α-pyrrolidinohexanophenone (α-PHP), and assessed the relationship between the toxicokinetics and the long-term clinical symptoms induced by α-PHP in a male patient. The patient (39 years old) suddenly started uttering inarticulate words and demonstrating incomprehensible behavior in his house, and was brought to the emergency department of Iwate Medical University hospital. He presented with psychotic symptoms, such as hallucinations and delusion; however, his vital signs were normal. The hallucinations and delusion improved by the third day of hospitalization. Toxicological analysis was performed using liquid chromatography-tandem mass spectrometry with QuEChERS extraction. α-PHP was detected in his serum at a concentration of 175 ng/mL on his arrival at the hospital. His serum concentrations of α-PHP were serially determined and their natural logarithms were plotted against time after arrival. Although serum concentrations at early time points were lacking, the obtained curve was consistent with a two-compartment model and indicated a serum elimination half-life of 37 h. The long-lasting psychotic symptoms induced by synthetic cathinones appear to be correlated with their toxicokinetic characteristics, such as their long half-lives. Finally, interpreting the toxicokinetics of synthetic cathinones may provide useful information for the toxicological assessment of new psychoactive substances for forensic and clinical purposes.

Fatal Poisonings Associated with New Psychoactive Substances

This chapter describes how new psychoactive substances (NPS) have been involved in fatal intoxications from 2010 and onwards. It summarizes the circumstances, antemortem symptoms, and adverse effects that have led to death after ingestion of one or more NPS and tabulates concentrations, and postmortem findings from these intoxications.Consumption of NPS exerts health problems and unknown risks for the users. Data on toxicity of many NPS are scarce or nonexistent and long-term toxicity and risks are still largely unknown. In addition, purity and composition of products containing NPS are often inconsistent or not known, which places users at high risk as evidenced by hospital emergency admissions and deaths.The most serious threat to drug users are the synthetic opioids that with strong central nervous depressant effects have caused numerous accidental deaths spread over the entire globe. The synthetic cannabinoids seem to be the most unpredictable with no clear toxidrome and unknown or poorly understood mechanisms of toxicity, but with adverse effects pointing toward the cardiovascular system. The toxidromes commonly encountered after ingestion of cathinones and phenethylamines are of sympathomimetic and hallucinogenic character, which includes risk of developing a serotonin syndrome, excited delirium, and life-threatening cardiovascular effects. In comparison to their conventional "parent" drug, i.e., heroin, cannabis, and amphetamine, most NPS appear to exhibit more severe adverse effects. The deaths attributed to NPS have dramatically increased in the last years. In our opinion, this is because of the shift from synthetic cannabinoids and cathinones to the even more toxic and dangerously potent fentanyl analogues.

Interactions of Cathinone NPS with Human Transporters and Receptors in Transfected Cells

Pharmacological assays carried out in transfected cells have been very useful for describing the mechanism of action of cathinone new psychoactive substances (NPS). These in vitro characterizations provide fast and reliable information on psychoactive substances soon after they emerge for recreational use. Well-investigated comparator compounds, such as methamphetamine, 3,4-methylenedioxymethamphetamine, cocaine, and lysergic acid diethylamide, should always be included in the characterization to enhance the translation of the in vitro data into clinically useful information. We classified cathinone NPS according to their pharmacology at monoamine transporters and receptors. Cathinone NPS are monoamine uptake inhibitors and most induce transporter-mediated monoamine efflux with weak to no activity at pre- or postsynaptic receptors. Cathinones with a nitrogen-containing pyrrolidine ring emerged as NPS that are extremely potent transporter inhibitors but not monoamine releasers. Cathinones exhibit clinically relevant differences in relative potencies at serotonin vs. dopamine transporters. Additionally, cathinone NPS have more dopaminergic vs. serotonergic properties compared with their non-β-keto amphetamine analogs, suggesting more stimulant and reinforcing properties. In conclusion, in vitro pharmacological assays in heterologous expression systems help to predict the psychoactive and toxicological effects of NPS.

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.

The Toxicology of New Psychoactive Substances: Synthetic Cathinones and Phenylethylamines

BACKGROUND

New psychoactive substances (NPSs) are substitutes for classical drugs of abuse and there are now compounds available from all groups of classical drugs of abuse. During 2014, the number of synthetic cathinones increased dramatically and, together with phenylethylamines, they dominate the NPS markets in the European Union. In total, 31 cathinones and 9 phenylethylamines were encountered in 2014. The aim of this article was to summarize the existing knowledge about the basic pharmacology, metabolism, and human toxicology of relevant synthetic cathinones and phenylethylamines. Compared with existing reviews, we have also compiled the existing case reports from both fatal and nonfatal intoxications.

METHODS

We performed a comprehensive literature search using bibliographic databases PubMed and Web of Science, complemented with Google Scholar. The focus of the literature search was on original articles, case reports, and previously published review articles published in 2014 or earlier.

RESULTS

The rapid increase of NPSs is a growing concern and sets new challenges not only for societies in drug prevention and legislation but also in clinical and forensic toxicology. In vivo and in vitro studies have demonstrated that the pharmacodynamic profile of cathinones is similar to that of other psychomotor stimulants. Metabolism studies show that cathinones and phenylethylamines are extensively metabolized; however, the parent compound is usually detectable in human urine. In vitro studies have shown that many cathinones and phenylethylamines are metabolized by CYP2D6 enzymes. This indicates that these drugs may have many possible drug-drug interactions and that genetic polymorphism may influence their toxicity. However, the clinical and toxicological relevance of CYP2D6 in adverse effects of cathinones and phenylethylamines is questionable, because these compounds are metabolized by other enzymes as well. The toxidromes commonly encountered after ingestion of cathinones and phenylethylamines are mainly of sympathomimetic and hallucinogenic character with a risk of excited delirium and life-threatening cardiovascular effects.

CONCLUSIONS

The acute and chronic toxicity of many NPSs is unknown or very sparsely investigated. There is a need for evidence-based-treatment recommendations for acute intoxications and a demand for new strategies to analyze these compounds in clinical and forensic cases.

Synthetic cathinone pharmacokinetics, analytical methods, and toxicological findings from human performance and postmortem cases

Synthetic cathinones are commonly abused novel psychoactive substances (NPS). We present a comprehensive systematic review addressing in vitro and in vivo synthetic cathinone pharmacokinetics, analytical methods for detection and quantification in biological matrices, and toxicological findings from human performance and postmortem toxicology cases. Few preclinical administration studies examined synthetic cathinone pharmacokinetic profiles (absorption, distribution, metabolism, and excretion), and only one investigated metabolite pharmacokinetics. Synthetic cathinone metabolic profiling studies, primarily with human liver microsomes, elucidated metabolite structures and identified suitable biomarkers to extend detection windows beyond those provided by parent compounds. Generally, cathinone derivatives underwent ketone reduction, carbonylation of the pyrrolidine ring, and oxidative reactions, with phase II metabolites also detected. Reliable analytical methods are necessary for cathinone identification in biological matrices to document intake and link adverse events to specific compounds and concentrations. NPS analytical methods are constrained in their ability to detect new emerging synthetic cathinones due to limited commercially available reference standards and continuous development of new analogs. Immunoassay screening methods are especially affected, but also gas-chromatography and liquid-chromatography mass spectrometry confirmation methods. Non-targeted high-resolution-mass spectrometry screening methods are advantageous, as they allow for retrospective data analysis and easier addition of new synthetic cathinones to existing methods. Lack of controlled administration studies in humans complicate interpretation of synthetic cathinones in biological matrices, as dosing information is typically unknown. Furthermore, antemortem and postmortem concentrations often overlap and the presence of other psychoactive substances are typically found in combination with cathinones derivatives, further confounding result interpretation.

Bath Salt-Induced Psychosis: Nursing Assessment, Diagnosis, Treatment, and Outcomes

PURPOSE

To review what is known about the assessment, diagnosis, treatment, and outcomes of patients with bath salt-induced psychosis.

DESIGN AND METHODS

Comprehensive review and synthesis of research, case reports, and state-level data.

FINDINGS

Of the 42 case reports found, only 18 confirmed the presence of bath salts through laboratory testing. Twelve of the confirmed cases died. In most of the case reports, law enforcement was involved prior to hospitalization due to bizarre behaviors, delusions, and hallucinations.

PRACTICE IMPLICATIONS

Due to the severity of both physical and psychological symptoms in patients in bath salt-induced psychosis, nurses, other healthcare providers, police, and hospital security personnel must work collaboratively to provide safe care.

Clinical and toxicological findings of acute intoxication with synthetic cannabinoids and cathinones

Aim

Reporting of the analytical and clinical findings of synthetic cannabinoids and cathinones is essential in carrying out a complete clinical assessment of new psychoactive substances.

Methods

From 2012 to 2014, we examined synthetic cathinone and cannabinoid poisoning in six patients aged 22-42 years old. Analyses of these compounds were carried out using liquid chromatography-tandem mass spectrometry.

Results

The observed clinical symptoms were similar to those reported for intoxication with synthetic cathinones and cannabinoids. In cases of intoxication with synthetic cathinones, the psychiatric and neurological symptoms were long-lasting, and these compounds were detected in serum for 15-48 h after use. Although the clinical symptoms induced by the synthetic cannabinoids disappeared within several hours after use, the range of serum concentrations of these compounds was ≤5 ng/mL for 1-3 h after use. In one fatal case, in which high serum concentrations of synthetic cathinones and cannabinoids were detected, the most plausible cause of death was heart failure due to overdose with these drugs. The long-lasting symptoms induced by synthetic cathinones correlated with the long detection window in serum, whereas the early disappearance of symptoms induced by synthetic cannabinoids corresponded to the short detection window in serum.

Conclusions

This study shows that the profiles of synthetic cathinones and cannabinoids in serum are closely related to the duration of the toxic symptoms and that concomitant use of two psychoactive drugs with different pharmacological actions may have the potential for fatal cardiotoxicity.

Monoamine transporter and receptor interaction profiles of novel psychoactive substances: para-halogenated amphetamines and pyrovalerone cathinones

The pharmacology of novel psychoactive substances is mostly unknown. We evaluated the transporter and receptor interaction profiles of a series of para-(4)-substituted amphetamines and pyrovalerone cathinones. We tested the potency of these compounds to inhibit the norepinephrine (NE), dopamine (DA), and serotonin (5-HT) transporters (NET, DAT, and SERT, respectively) using human embryonic kidney 293 cells that express the respective human transporters. We also tested the substance-induced efflux of NE, DA, and 5-HT from monoamine-loaded cells, binding affinities to monoamine receptors, and 5-HT2B receptor activation. Para-(4)-substituted amphetamines, including 4-methylmethcathinone (mephedrone), 4-ethylmethcathinone, 4-fluoroamphetamine, 4-fluoromethamphetamine, 4-fluoromethcatinone (flephedrone), and 4-bromomethcathinone, were relatively more serotonergic (lower DAT:SERT ratio) compared with their analogs amphetamine, methamphetamine, and methcathinone. The 4-methyl, 4-ethyl, and 4-bromo groups resulted in enhanced serotonergic properties compared with the 4-fluoro group. The para-substituted amphetamines released NE and DA. 4-Fluoramphetamine, 4-flouromethamphetamine, 4-methylmethcathinone, and 4-ethylmethcathinone also released 5-HT similarly to 3,4-methylenedioxymethamphetamine. The pyrovalerone cathinones 3,4-methylenedioxypyrovalerone, pyrovalerone, α-pyrrolidinovalerophenone, 3,4-methylenedioxy-α-pyrrolidinopropiophenone, and 3,4-methylenedioxy-α-pyrrolidinobutiophenone potently inhibited the NET and DAT but not the SERT. Naphyrone was the only pyrovalerone that also inhibited the SERT. The pyrovalerone cathinones did not release monoamines. Most of the para-substituted amphetamines exhibited affinity for the 5-HT2A receptor but no relevant activation of the 5-HT2B receptor. All the cathinones exhibited reduced trace amine-associated receptor 1 binding compared with the non-β-keto-amphetamines. In conclusion, para-substituted amphetamines exhibited enhanced direct and indirect serotonergic agonist properties and are likely associated with more MDMA-like effects. The pharmacological profile of the pyrovalerone cathinones predicts pronounced stimulant effects and high abuse liability.

Emerging drugs of abuse: current perspectives on substituted cathinones

Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines.

Validation of the only commercially available immunoassay for synthetic cathinones in urine: Randox Drugs of Abuse V Biochip Array Technology

Deterrence of synthetic cathinone abuse is hampered by the lack of a high-throughput immunoassay screen. The Randox Drugs of Abuse V (DOA-V) Biochip Array Technology contains two synthetic cathinone antibodies: Bath Salt I (BSI) targets mephedrone/methcathinone and Bath Salt II (BSII) targets 3',4'-methylenedioxypyrovalerone (MDPV)/3',4'-methylenedioxy-α-pyrrolidinobutiophenone (MDPBP). We evaluated DOA-V synthetic cathinones performance and conducted a full validation on the original assay with calibrators reconstituted in water, and the new assay with calibrators prepared in lyophilized urine; both utilized the same antibodies and were run on the fully automated Evidence® Analyzer. We screened 20 017 authentic military urine specimens and confirmed positives by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for 28 synthetic cathinones. Limits of detection (LOD) for the original and new assays were 0.35 and 0.18 (BSI), and 8.5 and 9.2 µg/L (BSII), respectively. Linearity was acceptable (R(2)  >0.98); however, a large negative bias was observed with in-house prepared calibrators. Intra-assay imprecision was <20% BSI-II, while inter-assay imprecision was 18-42% BSI and <22% BSII. Precision was acceptable for Randox controls. Cross-reactivities of many additional synthetic cathinones were determined. Authentic drug-free negative urine pH <4 produced false positive results for BSI (6.3 µg/L) and BSII (473 µg/L). Oxidizing agents reduced BSI and increased BSII results. Sensitivity, specificity, and efficiency of 100%, 52.1%, and 53.0% were obtained at manufacturer's proposed cut-offs (BSI 5 µg/L, BSII 30 µg/L). Performance improved if cut-off concentrations increased (BSI 7.5 µg/L, BSII 40 µg/L); however, there were limited confirmed positive specimens. Currently, this is the first and only fully validated immunoassay for preliminary detection of synthetic cathinones in urine. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Pharmacological profiles of aminoindanes, piperazines, and pipradrol derivatives

Aminoindanes, piperazines, and pipradrol derivatives are novel psychoactive substances found in "Ecstasy" tablets as replacements for 3,4-methylenedioxymethamphetamine (MDMA) or substances sold as "ivory wave." The pharmacology of these MDMA- and methylphenidate-like substances is poorly known. We characterized the pharmacology of the aminoindanes 5,6-methylenedioxy-2-aminoindane (MDAI), 5-iodoaminoindane (5-IAI), and 2-aminoindane (2-AI), the piperazines meta-chlorophenylpiperazine (m-CPP), trifluoromethylphenylpiperazine (TFMPP), and 1-benzylpiperazine (BZP), and the pipradrol derivatives desoxypipradrol (2-diphenylmethylpiperidine [2-DPMP]), diphenylprolinol (diphenyl-2-pyrrolidinemethanol [D2PM]), and methylphenidate. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-hydroxytryptamine [5-HT]) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporters (NET, DAT, and SERT). We also evaluated the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells and the binding affinity to monoamine transporters and receptors, including trace amine-associated receptor 1 (TAAR1). 5-IAI and MDAI preferentially inhibited the SERT and NET and released 5-HT. 2-AI interacted with the NET. BZP blocked the NET and released DA. m-CPP and TFMPP interacted with the SERT and serotonergic receptors. The pipradrol derivatives were potent and selective catecholamine transporter blockers without substrate releasing properties. BZP, D2PM, and 2-DPMP lacked serotonergic activity and TAAR1 binding, in contrast to the aminoindanes and phenylpiperazines. In summary, all of the substances were monoamine transporter inhibitors, but marked differences were found in their DAT vs. SERT inhibition profiles, release properties, and receptor interactions. The pharmacological profiles of D2PM and 2-DPMP likely predict a high abuse liability.

Khat and synthetic cathinones: a review

For centuries, 'khat sessions' have played a key role in the social and cultural traditions among several communities around Saudi Arabia and most East African countries. The identification of cathinone as the main psychoactive compound of khat leaves, exhibiting amphetamine-like pharmacological properties, resulted in the synthesis of several derivatives structurally similar to this so-called natural amphetamine. Synthetic cathinones were primarily developed for therapeutic purposes, but promptly started being misused and extensively abused for their euphoric effects. In the mid-2000's, synthetic cathinones emerged in the recreational drug markets as legal alternatives ('legal highs') to amphetamine, 'ecstasy', or cocaine. Currently, they are sold as 'bath salts' or 'plant food', under ambiguous labels lacking information about their true contents. Cathinone derivatives are conveniently available online or at 'smartshops' and are much more affordable than the traditional illicit drugs. Despite the scarcity of scientific data on these 'legal highs', synthetic cathinones use became an increasingly popular practice worldwide. Additionally, criminalization of these derivatives is often useless since for each specific substance that gets legally controlled, one or more structurally modified analogs are introduced into the legal market. Chemically, these substances are structurally related to amphetamine. For this reason, cathinone derivatives share with this drug both central nervous system stimulating and sympathomimetic features. Reports of intoxication and deaths related to the use of 'bath salts' have been frequently described over the last years, and several attempts to apply a legislative control on synthetic cathinones have been made. However, further research on their pharmacological and toxicological properties is fully required in order to access the actual potential harm of synthetic cathinones to general public health. The present work provides a review on khat and synthetic cathinones, concerning their historical background, prevalence, patterns of use, legal status, chemistry, pharmacokinetics, pharmacodynamics, and their physiological and toxicological effects on animals and humans.

Emergence and properties of spice and bath salts: a medicinal chemistry perspective

Over the past five years the number of internet sites advertising "legal highs" has literally exploded, as have user reports of experiences (both pleasurable and frightening) with these substances and the number of emergency room visits by users. Although the majority of these "legal highs" have been described as bath salts and herbal extracts, most contain neither plant derived compounds nor components of personal hygiene products. So-called "bath salts" largely contain synthetic analogs of the natural compound Khat; spice-related materials, claimed to be "legal marijuana," are mostly synthetic analogs of cannabinoid receptor ligands that were developed as research tools. This review describes the emergence and properties of these two groups of "legal highs" from a medicinal chemist's perspective.

Clinical and pharmacological aspects of bath salt use: a review of the literature and case reports

Bath salts are designer drugs with stimulant properties that are a growing medical and psychiatric concern due to their widespread availability and use. Although the chemical compounds in the mixtures referred to as "bath salts" vary, many are derivatives of cathinone, a monoamine alkaloid. Cathinones have an affinity for dopamine, serotonin, and norepinephrine synapses in the brain. Because of the strong selection for these neurotransmitters, these drugs induce stimulating effects similar to those of methamphetamines, cocaine, and 3,4-methylenedioxy-N-methylamphetamine (MDMA). Much of the emerging information about bath salts is from emergency department evaluation and treatment of severe medical and neuropsychiatric adverse outcomes. This review consists of a compilation of case reports and describes the emergent literature that illustrates the chemical composition of bath salts, patterns of use, administration methods, medical and neuropsychiatric effects, and treatments of patients with bath salt toxicity.

Synthetic cathinone abuse

The abuse of synthetic cathinones, widely known as bath salts, has been increasing since the mid-2000s. These substances are derivatives of the naturally occurring compound cathinone, which is the primary psychoactive component of khat. The toxicity of synthetic cathinones includes significant sympathomimetic effects, as well as psychosis, agitation, aggression, and sometimes violent and bizarre behavior. Mephedrone and methylenedioxypyrovalerone are currently the predominantly abused synthetic cathinones.

Recreational use of 1-(2-naphthyl)-2-(1-pyrrolidinyl)-1-pentanone hydrochloride (NRG-1), 6-(2-aminopropyl) benzofuran (benzofury/ 6-APB) and NRG-2 with review of available evidence-based literature

OBJECTIVE

This study aimed to review the available evidence-based literature on novel psychoactive substances and to inform health care professionals.

METHODS

Internet searches were carried out using Google and Yahoo by using specific key words. For each set of key words, the first 100 websites identified by Google and Yahoo were fully assessed, together with a further 5% of random samples selected by research randomizer of the remaining websites. Thus, a list of unique web forums was identified, and qualitative information was extracted. Available evidence-based literature were reviewed along with a user's experimentation with mephedrone, NRG-1, NRG-2 and Benzofury.

RESULTS

It showed that when a substance (mephedrone) became controlled, the vendors aggressively promote the sale of other new compounds (NRG-1, NRG-2, Benzofury) to attract vulnerable adults. The characteristics, toxicity and suggested management of these new compounds (NRG-1, NRG-2, Benzofury) are discussed.

CONCLUSIONS

The arrival of hundreds of novel psychoactive substances for sale online has raised a number of public health and legal issues. Although evidence-based literature remains limited, few studies identified that most products do not contain the ingredients as advertised. Better levels of international cooperation and rapid share of available information may be needed to tackle this emerging problem.

Designer cathinones--an emerging class of novel recreational drugs

A new group of recreational drugs, popularly known as "bath salts", "plant feeders" or "plant food", has recently emerged in numerous countries. Although various products are labeled with warnings "not for human consumption" or "not tested for hazards or toxicity", they are intended to produce a high similar to that obtained with illegal stimulants, such as MDMA, methamphetamine or cocaine. The active compounds in "bath salts" are cathinone derivatives continuously developed and modified by drug designers to avoid detection or legal scrutiny. Around 2010 the most prevalent were mephedrone (4-methylmethcathinone) and MDPV (3,4-methylenedioxypyrovalerone). This review surveys the current state of knowledge regarding the pharmacotoxicological properties of synthetic cathinones, the prevalence and pattern of their use. Special emphasis is given to the negative consequences of using these products including, among others, cardiovascular, psychiatric and neurologic symptoms, dehydration, rhambdomyolysis, renal and liver failure. Case reports on synthetic cathinones-related fatalities are also presented.

Substituted methcathinones differ in transporter and receptor interactions

The use of synthetic methcathinones, components of "bath salts," is a world-wide health concern. These compounds, structurally similar to methamphetamine (METH) and 3,4-methylendioxymethamphetamine (MDMA), cause tachycardia, hallucinations and psychosis. We hypothesized that these potentially neurotoxic and abused compounds display differences in their transporter and receptor interactions as compared to amphetamine counterparts. 3,4-Methylenedioxypyrovalerone and naphyrone had high affinity for radioligand binding sites on recombinant human dopamine (hDAT), serotonin (hSERT) and norepinephrine (hNET) transporters, potently inhibited [³H]neurotransmitter uptake, and, like cocaine, did not induce transporter-mediated release. Butylone was a lower affinity uptake inhibitor. In contrast, 4-fluoromethcathinone, mephedrone and methylone had higher inhibitory potency at uptake compared to binding and generally induced release of preloaded [³H]neurotransmitter from hDAT, hSERT and hNET (highest potency at hNET), and thus are transporter substrates, similar to METH and MDMA. At hNET, 4-fluoromethcathinone was a more efficacious releaser than METH. These substituted methcathinones had low uptake inhibitory potency and low efficacy at inducing release via human vesicular monoamine transporters (hVMAT2). These compounds were low potency (1) h5-HT(1A) receptor partial agonists, (2) h5-HT(2A) receptor antagonists, (3) weak h5-HT(2C) receptor antagonists. This is the first report on aspects of substituted methcathinone efficacies at serotonin (5-HT) receptors and in superfusion release assays. Additionally, the drugs had no affinity for dopamine receptors, and high-nanomolar to mid-micromolar affinity for hSigma1 receptors. Thus, direct interactions with hVMAT2 and serotonin, dopamine, and hSigma1 receptors may not explain psychoactive effects. The primary mechanisms of action may be as inhibitors or substrates of DAT, SERT and NET.

Identification of substituted cathinones: 3,4-Methylenedioxy derivatives by high performance liquid chromatography-quadrupole time of flight mass spectrometry

The potential of high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) for screening of synthetic cathinones in legal highs was examined. Samples were analysed by liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometer (Q/TOF). Nanoelectrospray ionisation (nanoESI) was employed. MS and MS/MS spectra were acquired. Six 3,4-methylenedioxy derivatives: methylone, butylone, pentylone, MDPBP, MDPV and BMDP were detected and identified. The fragmentation pattern of 3,4-methylenedioxy derivatives in collision induced dissociation (CID) was derived and described, which will facilitate future screenings and identifications of new synthetic cathinones. For 3,4-methylenodioxy derivative cathinones the loss of neutral groups CH₄O₂, H₂O, amines and imines is observed. The loss of water and the methylenedioxy group does not occur when cyclic amino group - pyrrolidynyl is present in the molecule. Phenyloxazole cations are formed when CH₄O₂ is lost. The formation of the metylenedioxybenzoyloxonium and allyldioxybenzoyloxonium ions is typical for 3,4-methylenodioxy derivatives, however, the formation of the former appears to be inhibited by the presence in the molecule of the group of atoms able to form very stable tropylium carbocation.

Pharmacological characterization of designer cathinones in vitro

BACKGROUND AND PURPOSE

Designer β-keto amphetamines (e.g. cathinones, 'bath salts' and 'research chemicals') have become popular recreational drugs, but their pharmacology is poorly characterized.

EXPERIMENTAL APPROACH

We determined the potencies of cathinones to inhibit DA, NA and 5-HT transport into transporter-transfected HEK 293 cells, DA and 5-HT efflux from monoamine-preloaded cells, and monoamine receptor binding affinity.

KEY RESULTS

Mephedrone, methylone, ethylone, butylone and naphyrone acted as non-selective monoamine uptake inhibitors, similar to cocaine. Mephedrone, methylone, ethylone and butylone also induced the release of 5-HT, similar to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and other entactogens. Cathinone, methcathinone and flephedrone, similar to amphetamine and methamphetamine, acted as preferential DA and NA uptake inhibitors and induced the release of DA. Pyrovalerone and 3,4-methylenedioxypyrovalerone (MDPV) were highly potent and selective DA and NA transporter inhibitors but unlike amphetamines did not evoke the release of monoamines. The non-β-keto amphetamines are trace amine-associated receptor 1 ligands, whereas the cathinones are not. All the cathinones showed high blood-brain barrier permeability in an in vitro model; mephedrone and MDPV exhibited particularly high permeability.

CONCLUSIONS AND IMPLICATIONS

Cathinones have considerable pharmacological differences that form the basis of their suggested classification into three groups. The predominant action of all cathinones on the DA transporter is probably associated with a considerable risk of addiction.