Recurrent seizures and serotonin syndrome following "2C-I" ingestion

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

Knowledge and Use of Novel Psychoactive Substances in an Italian Sample with Substance Use Disorders

This study aims to determine prevalence and frequency of use of novel psychoactive substances (NPS) and to identify the factors associated with NPS use in an Italian sample of patients diagnosed with substance use disorder (SUD). Prevalence and correlates of NPS knowledge and use were assessed in 185 patients with SUD in three addiction services (Padova, Belluno, Feltre) in the Veneto region with an ad-hoc designed survey. Two thirds of the samples reported knowing NPS and one third reported using them. NPS were considered by them less dangerous than "regular" substances of abuse (t = 6.06 mean 0.78, p < 0.001). Factors associated with NPS use were youth (OR = 4.81; p < 0.001), studentship (OR = 4.99; p = 0.004), subsequent mental disorders diagnosis (OR = 2.49; p = 0.027), suicide attempt history (OR = 11.67; p < 0.001), home detention (OR = 2.30; p = 0.040), residential care (OR = 5.66; p = 0.002), and polysubstance abuse (t = 8.99 mean 2.65 p < 0.001). NPS use in patients with SUD is highly prevalent, particularly in the youngest age group, and associated with psychiatric comorbidity and worse prognosis. It is crucial to systematically assess NPS use and inform addiction service users with SUD of the toxic and potentially lethal side effects. Mental healthcare professionals working in addiction services should receive education and training. Cohort and longitudinal studies are needed.

Human Neuronal Cell Lines as An In Vitro Toxicological Tool for the Evaluation of Novel Psychoactive Substances

Novel psychoactive substances (NPS) are synthetic substances belonging to diverse groups, designed to mimic the effects of scheduled drugs, resulting in altered toxicity and potency. Up to now, information available on the pharmacology and toxicology of these new substances is very limited, posing a considerable challenge for prevention and treatment. The present in vitro study investigated the possible mechanisms of toxicity of two emerging NPS (i) 4′-methyl-alpha-pyrrolidinoexanophenone (3,4-MDPHP), a synthetic cathinone, and (ii) 2-chloro-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA), a phenethylamine. In addition, to apply our model to the class of synthetic opioids, we evaluated the toxicity of fentanyl, as a reference compound for this group of frequently abused substances. To this aim, the in vitro toxic effects of these three compounds were evaluated in dopaminergic-differentiated SH-SY5Y cells. Following 24 h of exposure, all compounds induced a loss of viability, and oxidative stress in a concentration-dependent manner. 2-Cl-4,5-MDMA activates apoptotic processes, while 3,4-MDPHP elicits cell death by necrosis. Fentanyl triggers cell death through both mechanisms. Increased expression levels of pro-apoptotic Bax and caspase 3 activity were observed following 2-Cl-4,5-MDMA and fentanyl, but not 3,4-MDPHP exposure, confirming the different modes of cell death.

New Designer Drugs

In recent years, there has been an emergence of numerous novel drugs. Such toxicity may occur in both adolescents and adults. This article discusses the opioid epidemic and several emerging opioids, including buprenorphine, loperamide, fentanyl, fentanyl derivatives, and others. Kratom, a plant occasionally used for opiate detoxification, along with the sedatives etizolam and phenibut, will be discussed. Lastly, this article discusses the phenethylamines and marijuana.

Molecular and clinical aspects of potential neurotoxicity induced by new psychoactive stimulants and psychedelics

New psychoactive stimulants and psychedelics continue to play an important role on the illicit new psychoactive substance (NPS) market. Designer stimulants and psychedelics both affect monoaminergic systems, although by different mechanisms. Stimulant NPS primarily interact with monoamine transporters, either as inhibitors or as substrates. Psychedelic NPS most potently interact with serotonergic receptors and mediate their mind-altering effects mainly through agonism at serotonin 5-hydroxytryptamine-2A (5-HT_2A) receptors. Rarely, designer stimulants and psychedelics are associated with potentially severe adverse effects. However, due to the high number of emerging NPS, it is not possible to investigate the toxicity of each individual substance in detail. The brain is an organ particularly sensitive to substance-induced toxicity due to its high metabolic activity. In fact, stimulant and psychedelic NPS have been linked to neurological and cognitive impairments. Furthermore, studies using in vitro cell models or rodents indicate a variety of mechanisms that could potentially lead to neurotoxic damage in NPS users. Cytotoxicity, mitochondrial dysfunction, and oxidative stress may potentially contribute to neurotoxicity of stimulant NPS in addition to altered neurochemistry. Serotonin 5-HT_2A receptor-mediated toxicity, oxidative stress, and activation of mitochondrial apoptosis pathways could contribute to neurotoxicity of some psychedelic NPS. However, it remains unclear how well the current preclinical data of NPS-induced neurotoxicity translate to humans.

Novel Phenethylamines and Their Potential Interactions With Prescription Drugs: A Systematic Critical Review

BACKGROUND

The novel phenethylamines 4-fluoroamphetamine (4-FA) and 2,5-dimethoxy-4-bromophenethylamine (2C-B) fall in the top 10 most used new psychoactive substances (NPSs) among high-risk substance users. Various phenethylamines and NPS are also highly used in populations with mental disorders, depression, or attention deficit hyperactivity disorder (ADHD). Moreover, NPS use is highly prevalent among men and women with risky sexual behavior. Considering these specific populations and their frequent concurrent use of drugs, such as antidepressants, ADHD medication, and antiretrovirals, reports on potential interactions between these drugs, and phenethylamines 4-FA and 2C-B, were reviewed.

METHODS

The authors performed a systematic literature review on 4-FA and 2C-B interactions with antidepressants (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, bupropion, venlafaxine, phenelzine, moclobemide, and tranylcypromine), ADHD medications (atomoxetine, dexamphetamine, methylphenidate, and modafinil), and antiretrovirals.

RESULTS

Limited literature exists on the pharmacokinetics and drug-drug interactions of 2C-B and 4-FA. Only one case report indicated a possible interaction between 4-FA and ADHD medication. Although pharmacokinetic interactions between 4-FA and prescription drugs remain speculative, their pharmacodynamic points toward interactions between 4-FA and ADHD medication and antidepressants. The pharmacokinetic and pharmacodynamic profile of 2C-B also points toward such interactions, between 2C-B and prescription drugs such as antidepressants and ADHD medication.

CONCLUSIONS

A drug-drug (phenethylamine-prescription drug) interaction potential is anticipated, mainly involving monoamine oxidases for 2C-B and 4-FA, with monoamine transporters being more specific to 4-FA.

New psychoactive substances (NPS) and serotonin syndrome onset: A systematic review

The use of several new psychoactive substances (NPS) has become very popular and is posing global health risks. Chemically and pharmacologically diverse molecules are constantly emerging and are presenting with a wide range of clinical implications. Serotonin toxicity, and specifically Serotonin Syndrome (SS), might develop as a result of an over-activation of the serotoninergic system caused by several mechanisms resulting in a classic triad of altered mental status, neuromuscular effects, and autonomic hyperactivity. In the present systematic review, we have investigated and summarized the available evidence related to the association between SS and NPS intake. Three retrospective studies, two case series and five case reports were included in this systematic review; several NPS were found to be implicated in SS occurrence These include psychedelic phenethylamines, e.g. 2, 5-dimethoxy-4-iodophenethylamine (2C-I); 2-(4-Iodo-2,5-dimethoxyphenyl)- N-I[(2-methyoxyphenyl)methyl]ethanamine (25I-NBOMe); and 5-(2-aminopropyl)indole (5-IT); and synthetic cathinones, e.g. mephedrone; 3,4-methylenedioxypyrovalerone (MDPV); methylone; butylone; NRG3; alpha-methyltryptamine (AMT); methoxphenidine (MXP); and the antidepressant bupropion. Bupropion was here misused at high dosages and/or in combination with other licit/illicit serotonergic drugs. Whilst most substances were ingested orally, nasal insufflation (with both 5-IT and 2C-I) and sublingual administration of blotter paper (with 25I-NBOMe) were reported as well. Interestingly, the psychiatric history was negative for most subjects, apart from two cases. Clinicians should be aware of NPS potential risks and the severe consequences of their recreational use, including SS. Also, due to their undetectability in routine and common drug screenings, the diagnostic challenges posed by NPS should not be underestimated during the treatment of such patients.

Novel Psychoactive Phenethylamines: Impact on Genetic Material

Psychedelic and stimulating phenethylamines belong to the family of new psychoactive substances (NPS). The acute toxicity framework has begun to be investigated, while studies showing genotoxic potential are very limited or not available. Therefore, in order to fill this gap, the aim of the present work was to evaluate the genotoxicity by treating TK6 cells with 2C-H, 2C-I, 2C-B, 25B-NBOMe, and the popular 3,4-Methylenedioxymethylamphetamine (MDMA). On the basis of cytotoxicity and cytostasis results, we selected the concentrations (6.25–35 µM) to be used in genotoxicity analysis. We used the micronucleus (MN) as indicator of genetic damage and analyzed the MNi frequency fold increase by an automated flow cytometric protocol. All substances, except MDMA, resulted genotoxic; therefore, we evaluated reactive oxygen species (ROS) induction as a possible mechanism at the basis of the demonstrated genotoxicity. The obtained results showed a statistically significant increase in ROS levels for all genotoxic phenethylamines confirming this hypothesis. Our results highlight the importance of genotoxicity evaluation for a complete assessment of the risk associated also with NPS exposure. Indeed, the subjects who do not have hazardous behaviors or require hospitalization by using active but still “safe” doses could run into genotoxicity and in the well-known long-term effects associated.

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 (GABA_A) or GABA_B 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-HT_2A) 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.

Neurochemical and Behavioral Profiling in Male and Female Rats of the Psychedelic Agent 25I-NBOMe

4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe), commonly called “N-Bomb,” is a synthetic phenethylamine with psychedelic and entactogenic effects; it was available on the Internet both as a legal alternative to lysergic acid diethylamide (LSD) and as a surrogate of 3,4-methylenedioxy-methamphetamine (MDMA), but now it has been scheduled among controlled substances. 25I-NBOMe acts as full agonist on serotonergic 5-HT2A receptors. Users are often unaware of ingesting fake LSD, and several cases of intoxication and fatalities have been reported. In humans, overdoses of “N-Bomb” can cause tachycardia, hypertension, seizures, and agitation. Preclinical studies have not yet widely investigated the rewarding properties and behavioral effects of this compound in both sexes. Therefore, by in vivo microdialysis, we evaluated the effects of 25I-NBOMe on dopaminergic (DA) and serotonergic (5-HT) transmissions in the nucleus accumbens (NAc) shell and core, and the medial prefrontal cortex (mPFC) of male and female rats. Moreover, we investigated the effect of 25I-NBOMe on sensorimotor modifications as well as body temperature, nociception, and startle/prepulse inhibition (PPI). We showed that administration of 25I-NBOMe affects DA transmission in the NAc shell in both sexes, although showing different patterns; moreover, this compound causes impaired visual responses in both sexes, whereas core temperature is heavily affected in females, and the highest dose tested exerts an analgesic effect prominent in male rats. Indeed, this drug is able to impair the startle amplitude with the same extent in both sexes and inhibits the PPI in male and female rats. Our study fills the gap of knowledge on the behavioral effects of 25I-NBOMe and the risks associated with its ingestion; it focuses the attention on sex differences that might be useful to understand the trend of consumption as well as to recognize and treat intoxication and overdose symptoms.

Unexpected Serotonin Syndrome, Epileptic Seizures, and Cerebral Edema Following 2,5-dimethoxy-4-bromophenethylamine Ingestion

4‐bromo‐2,5‐dimethoxyphenethylamine (2C‐B) is a designer drug. In Europe, 2C‐B is easily obtained and used for recreational purposes. It is known for its stimulating effects similar to those of 3,4‐methylenedioxymethamphetamine, although in higher doses it has more hallucinogenic effects. Here, we report a case of 2C‐B ingestion, confirmed by liquid chromatography‐tandem mass spectrometry, in an 18‐year‐old man. The neurological consequences were severe, including the development of serotonin syndrome and severe brain edema. Supportive therapy resulted in a stable condition, although, after several months, the patient still suffered from severe neurological impairment due to the drug‐induced toxicity. This case showed that 2C‐B could not be identified with the drugs of abuse screening routinely used in Dutch hospitals. The use of 2C‐B carries many risks, with potentially profound neurological damage, that both consumers and healthcare physicians are unaware of.

Management of severe arterial hypertension associated with serotonin syndrome: a case report analysis based on systematic review techniques

Serotonin syndrome is thought to arise from serotonin excess. In many cases, symptoms are mild and self-limiting. But serotonin syndrome can become life threatening, when neuromuscular hyperexcitability spins out of control. Uncontainable neuromuscular hyperexcitability may lead to cardiovascular complications, linked to extreme changes in blood pressure. Currently, there is little guidance on how to control blood pressure in hyperserotonergic states. We report a case with treatment-resistant arterial hypertension, followed by a clinical review (using systematic review principles and techniques) of the available evidence from case reports published between 2004 and 2016 to identify measures to control arterial hypertension associated with serotonin syndrome. We conclude that classic antihypertensives may not be effective for the treatment of severe hypertension associated with serotonin syndrome. Benzodiazepines may lower blood pressure. Patients with severe hypertension not responding to benzodiazepines may benefit from cyproheptadine, propofol or both. In severe cases, higher cyproheptadine doses than currently recommended may be necessary.

Comparison of the behavioral responses induced by phenylalkylamine hallucinogens and their tetrahydrobenzodifuran ("FLY") and benzodifuran ("DragonFLY") analogs

In recent years, rigid analogs of phenylalkylamine hallucinogens have appeared as recreational drugs. Examples include 2-(8-bromo-2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)ethan-1-amine (2C-B-FLY) and 1-(8-bromobenzo[1,2-b;4,5-b']difuran-4-yl)-2-aminopropane (Bromo-DragonFLY, DOB-DFLY). Although some rigid compounds such as DOB-DFLY reportedly have higher potency than their non-rigid counterparts, it is not clear whether the same is true for 2C-B-FLY and other tetrahydrobenzodifurans. In the present study, the head twitch response (HTR), a 5-HT2A receptor-mediated behavior induced by serotonergic hallucinogens, was used to assess the effects of 2,5-dimethoxy-4-bromoamphetamine (DOB) and its α-desmethyl homologue 2,5-dimethoxy-4-bromophenethylamine (2C-B), as well as their benzodifuranyl and tetrahydrobenzodifuranyl analogs, in C57BL/6J mice. DOB (ED50 = 0.75 μmol/kg) and 2C-B (ED50 = 2.43 μmol/kg) induced the HTR. The benzodifurans DOB-DFLY (ED50 = 0.20 μmol/kg) and 2C-B-DFLY (ED50 = 1.07 μmol/kg) had significantly higher potency than DOB and 2C-B, respectively. The tetrahydrobenzodifurans DOB-FLY (ED50 = 0.67 μmol/kg) and 2C-B-FLY (ED50 = 1.79 μmol/kg), by contrast, were approximately equipotent with their non-rigid counterparts. Three novel tetrahydrobenzodifurans (2C-I-FLY, 2C-E-FLY and 2C-EF-FLY) were also active in the HTR assay but had relatively low potency. In summary, the in vivo potency of 2,5-dimethoxyphenylalkylamines is enhanced when the 2- and 5-methoxy groups are incorporated into aromatic furan rings, whereas potency is not altered if the methoxy groups are incorporated into dihydrofuran rings. The potency relationships for these compounds in mice closely parallel the human hallucinogenic data. The high potency of DOB-DFLY is probably linked to the presence of two structural features (a benzodifuran nucleus and an α-methyl group) known to enhance the potency of phenylalkylamine hallucinogens.

Two immunoassays for the detection of 2C-B and related hallucinogenic phenethylamines

INTRODUCTION

The use of new psychoactive substances as drugs of abuse has dramatically increased over the last years. Hallucinogenic phenethylamines gained particular popularity as they have both stimulating and psychedelic effects. Although generally perceived as safe, these illicit drugs pose a serious health risk; they have been linked to cases of severe poisoning or even deaths. Therefore, simple, cost-effective and reliable methods are needed for rapid determination of abused hallucinogens.

METHODS

For this purpose, two haptens derived from 2C-H were designed, synthesized and subsequently attached to a carrier protein. Polyclonal antibodies obtained from a rabbit immunized with one of the prepared immunogens were used for the development of two immunoassays.

RESULTS

In this study, a lateral flow immunoassay (LFIA) and an enzyme linked immunosorbent assay (ELISA) for the detection of 2C-B and related hallucinogenic phenethylamines in urine were developed. The presented LFIA is primarily suitable for on-site monitoring as it is simple and can provide a visual evidence of 2C-B presence within a few minutes. Its reasonable sensitivity (LOD_LFIA = 15 ± 7 ng mL^-1) allows detection of the drug presence in urine after acute exposure. For greater accuracy, highly sensitive ELISA (LOD_ELISA = 6 ± 3 pg mL^-1) is proposed for toxicological quantitative analyses of positive samples captured by the LFIA.

DISCUSSION

The comparison of the ELISA with the well-established UHPLC-MS-MS method shows excellent agreement of results, which confirms good potential of the ELISA to be used for routine analyses of 2C-B and related hallucinogenic phenethylamines of both main sub-families.

Comparative neuropharmacology of N-(2-methoxybenzyl)-2,5-dimethoxyphenethylamine (NBOMe) hallucinogens and their 2C counterparts in male rats

2,5-Dimethoxyphenethylamines (2C compounds) are 5-HT2A/2C receptor agonists that induce hallucinogenic effects. N-methoxybenzylation of 2C compounds markedly increases their affinity for 5-HT2A receptors, and two such analogs, 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25C-NBOMe) and 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe), have emerged in recreational drug markets. Here, we investigated the neuropharmacology of 25C-NBOMe and 25I-NBOMe in rats, as compared to their 2C analogs and the prototypical 5-HT2A/2C agonist 1-(4-iodo-2,5-dimethoxyphenyl)propan-2-amine (DOI). Compounds were tested in vitro using 5-HT2A receptor binding and calcium mobilization assays. For in vivo experiments, 25C-NBOMe (0.01-0.3 mg/kg), 25I-NBOMe (0.01-0.3 mg/kg), 2-(4-chloro-2,5-dimethoxyphenyl)ethanamine (2C-C) (0.1-3.0 mg/kg), 2-(4-iodo-2,5-dimethoxyphenyl)ethanamine (2C-I) (0.1-3.0 mg/kg) and DOI (0.03-1.0 mg/kg) were administered subcutaneously (sc) to male rats, and 5-HT2A-mediated behaviors were assessed. NBOMes displayed higher affinity for 5-HT2A receptors than their 2C counterparts but were substantially weaker in functional assays. 25C-NBOMe and 25I-NBOMe were much more potent at inducing wet dog shakes (WDS) and back muscle contractions (BMC) when compared to 2C-C and 2C-I. Pretreatment with the selective 5-HT2A antagonist (R)-(2,3-dimethoxyphenyl){1-[2-(4-fluorophenyl)ethyl]-4-piperidinyl}methanol (M100907) reversed behaviors produced by all agonists. Interestingly, binding affinities at the 5-HT2A receptor were significantly correlated with potencies to induce BMC but not WDS. Our findings show that NBOMes are highly potent 5-HT2A agonists in rats, similar to effects in mice, and consistent with the reported hallucinogenic effects in human users. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.

Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases

Psychoactive substances of the 2C-series (2Cs) are phenethylamine-derived designer drugs that can induce psychostimulant and hallucinogenic effects. Chemically, the classic 2Cs contain two methoxy groups in positions 2 and 5 of the phenyl ring, whereas substances of the so-called FLY series contain rigidified methoxy groups integrated in a 2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran core. One of the pharmacological features that has not been investigated in detail is the inhibition of monoamine oxidase (MAO). Inhibition of this enzyme can cause elevated monoamine levels that have been associated with adverse events such as agitation, nausea, vomiting, tachycardia, hypertension, or seizures. The aim of this study was to extend the knowledge surrounding the potential of MAO inhibition for 17 test drugs, which consisted of 12 2Cs (2C-B, 2C-D, 2C-E, 2C-H, 2C-I, 2C-N, 2C-P, 2C-T-2, 2C-T-7, 2C-T-21, bk-2C-B, and bk-2C-I) and five FLY analogs (2C-B-FLY, 2C-E-FLY, 2C-EF-FLY, 2C-I-FLY, and 2C-T-7-FLY). The extent of MAO inhibition was assessed using an established in vitro procedure based on heterologously expressed enzymes and analysis by hydrophilic interaction liquid chromatography-high resolution tandem mass spectrometry. Thirteen test drugs showed inhibition potential for MAO-A and 11 showed inhibition of MAO-B. In cases where MAO-A IC₅₀ values were determined, values ranged from 10 to 125 μM (7 drugs) and from 1.7 to 180 μM for MAO-B (9 drugs). In the absence of detailed clinical information on most test drugs, it is concluded that a pharmacological contribution of MAO inhibition cannot be excluded and that further studies are warranted.

New and Emerging Illicit Psychoactive Substances

Several novel psychoactive substances have emerged in recent years. Users are typically young men who use other substances. In the category of stimulants, cathinones ("bath salts") have predominated and can lead to agitation, psychosis, hyperthermia, and death. Synthetic cannabinoids ("spice") are more potent than marijuana and can lead to agitation, psychosis, seizures, and death. There are no rapid tests to identify these substances and general treatment includes benzodiazepines for agitation and supportive therapy. Many Synthetic opioids are potent analogues of fentanyl and carry a high risk of overdose. In addition, there are several designer benzodiazepines that have emerged.

Neuroleptic malignant syndrome and serotonin syndrome

The clinical manifestation of drug-induced abnormalities in thermoregulation occurs across a variety of drug mechanisms. The aim of this chapter is to review two of the most common drug-induced hyperthermic states, serotonin syndrome and neuroleptic malignant syndrome. Clinical features, pathophysiology, and treatment strategies will be discussed, in addition to differentiating between these two syndromes and differentiating them from other hyperthermic or febrile syndromes. Our goal is to both review the current literature and to provide a practical guide to identification and treatment of these potentially life-threatening illnesses. The diagnostic and treatment recommendations made by us, and by other authors, are likely to change with a better understanding of the pathophysiology of these syndromes.

Locomotor and discriminative stimulus effects of four novel hallucinogens in rodents

There has been increasing use of novel synthetic hallucinogenic compounds, 2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25B-NBOMe), 2-(4-chloro-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25C-NBOMe), 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine hydrochloride (25I-NBOMe), and N,N-diallyl-5-methoxy tryptamine (5-MeO-DALT), which have been associated with severe toxicities. These four compounds were tested for discriminative stimulus effects similar to a prototypical hallucinogen (-)-2,5-dimethoxy-4-methylamphetamine (DOM) and the entactogen (±)-3,4-methylenedioxymethamphetamine (MDMA). Locomotor activity in mice was tested to obtain dose range and time-course information. 25B-NBOMe, 25C-NBOMe, and 25I-NBOMe decreased locomotor activity. 5-MeO-DALT dose dependently increased locomotor activity, with a peak at 10 mg/kg. A higher dose (25 mg/kg) suppressed activity. 25B-NBOMe fully substituted (≥80%) in both DOM-trained and MDMA-trained rats at 0.5 mg/kg. However, higher doses produced much lower levels of drug-appropriate responding in both DOM-trained and MDMA-trained rats. 25C-NBOMe fully substituted in DOM-trained rats, but produced only 67% drug-appropriate responding in MDMA-trained rats at doses that suppressed responding. 25I-NBOMe produced 74-78% drug-appropriate responding in DOM-trained and MDMA-trained rats at doses that suppressed responding. 5-MeO-DALT fully substituted for DOM, but produced few or no MDMA-like effects. All of the compounds, except 25I-NBOMe, fully substituted for DOM, whereas only 25B-NBOMe fully substituted for MDMA. However, the failure of 25I-NBOMe to fully substitute for either MDMA or DOM was more likely because of its substantial rate-depressant effects than weak discriminative stimulus effects. All of the compounds are likely to attract recreational users for their hallucinogenic properties, but probably of much less interest as substitutes for MDMA. Although no acute adverse effects were observed at the doses tested, the substantial toxicities reported in humans, coupled with the high likelihood for illicit use, suggests that these compounds have the same potential for abuse as other, currently scheduled compounds.

Monoamine receptor interaction profiles of 4-thio-substituted phenethylamines (2C-T drugs)

BACKGROUND

4-Thio-substituted phenethylamines (2C-T drugs) are potent psychedelics with poorly defined pharmacological properties. Because of their psychedelic effects, 2C-T drugs are sometimes sold as new psychoactive substances (NPSs). The aim of the present study was to characterize the monoamine receptor and transporter interaction profiles of a series of 2C-T drugs.

METHODS

We determined the binding affinities of 2C-T drugs at monoamine receptors and transporters in human cells that were transfected with the respective receptors or transporters. We also investigated the functional activation of serotonergic 5-hydroxytryptamine 2A (5-HT_2A) and 5-HT_2B receptors, activation of human trace amine-associated receptor 1 (TAAR₁), and inhibition of monoamine uptake transporters.

RESULTS

2C-T drugs had high affinity for 5-HT_2A and 5-HT_2C receptors (1-54 nM and 40-350 nM, respectively). With activation potencies of 1-53 nM and 44-370 nM, the drugs were potent 5-HT_2A receptor and 5-HT_2B receptor, respectively, partial agonists. An exception to this were the benzylthiophenethylamines, which did not potently activate the 5-HT_2B receptor (EC₅₀ > 3000 nM). Furthermore, the compounds bound to serotonergic 5-HT_1A and adrenergic receptors. The compounds had high affinity for the rat TAAR₁ (5-68 nM) and interacted with the mouse but not human TAAR₁. The 2C-T drugs did not potently interact with monoamine transporters (K_i > 4000 nM).

CONCLUSION

The receptor binding profile of 2C-T drugs predicts psychedelic effects that are mediated by potent 5-HT₂ receptor interactions. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'

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.

Pharmacology and Toxicology of N-Benzylphenethylamine ("NBOMe") Hallucinogens

Serotonergic hallucinogens induce profound changes in perception and cognition. The characteristic effects of hallucinogens are mediated by 5-HT2A receptor activation. One class of hallucinogens are 2,5-dimethoxy-substituted phenethylamines, such as the so-called 2C-X compounds 2,5-dimethoxy-4-bromophenethylamine (2C-B) and 2,5-dimethoxy-4-iodophenethylamine (2C-I). Addition of an N-benzyl group to phenethylamine hallucinogens produces a marked increase in 5-HT2A-binding affinity and hallucinogenic potency. N-benzylphenethylamines ("NBOMes") such as N-(2-methoxybenzyl)-2,5-dimethoxy-4-iodophenethylamine (25I-NBOMe) show subnanomolar affinity for the 5-HT2A receptor and are reportedly highly potent in humans. Several NBOMEs have been available from online vendors since 2010, resulting in numerous cases of toxicity and multiple fatalities. This chapter reviews the structure-activity relationships, behavioral pharmacology, metabolism, and toxicity of members of the NBOMe hallucinogen class. Based on a review of 51 cases of NBOMe toxicity reported in the literature, it appears that rhabdomyolysis is a relatively common complication of severe NBOMe toxicity, an effect that may be linked to NBOMe-induced seizures, hyperthermia, and vasoconstriction.

NPS: Medical Consequences Associated with Their Intake

Over the last decade, the 'traditional' drug scene has been supplemented - but not replaced - by the emergence of a range of novel psychoactive substances (NPS), which are either newly created or existing drugs, including medications, now being used in novel ways. By the end of 2014, in excess of 500 NPS had been reported by a large number of countries in the world. Most recent data show, however, that synthetic cathinones, synthetic cannabinoids, and psychedelics/phenethylamines account for the largest number of NPS.The present chapter aims at providing an overview of the clinical and pharmacological issues relating to these most popular NPS categories. Given the vast range of medical and psychopathological issues associated with the molecules here described, it is crucial for health professionals to be aware of the effects and toxicity of NPS. A general overview of the acute management of NPS adverse events is provided as well, although further studies are required to identify a range of evidence-based, index molecule-focused, treatment strategies. The rapid pace of change in the NPS online market constitutes a major challenge to the provision of current and reliable scientific knowledge on these substances.

New synthetic drugs in addictovigilance

New substances, also known as "designer drugs" or "legal highs" are increasingly available to drug users. Two hundred and fifteen hitherto unlisted substances have been notified by European Union member states since 2005. These synthetic drugs, which have been developed to side-step the legislation on drugs, are analogues or derivatives of existing drugs and medications. The availability of these "legal highs", sold on Internet under various denominations such as bath salt, plant fertilizer, chemical not intended for human use, or spice, is unlimited. The effects felt by users vary, and the substances may be stimulant, entactogenic, hallucinogenic, psychedelic or dissociative. The pharmacological targets also vary, and may be either the increase of extracellular levels of neurotransmitters via different mechanisms (reuptake inhibition, stimulation of intracellular release) or else fixation on specific receptors. Several chemical classes, themselves divided into sub-classes, are involved: phenethylamines, tryptamines, piperazines, cathinones, cannabinoids etc. The toxicity of the main members of these categories is increasingly well known, the most deleterious being behavioural effects, physical manifestations, and cardiovascular consequences. However, small variations in their chemical structure can generate effects that are quantitatively different, thus enhancing their toxicity or addictive potential, and much remains to be achieved in terms of knowledge about these new drugs. These substances are indeed present on the French territory, as shown by data provided by the Observatoire Français des Drogues et Toxicomanies, and notifications by the French Addictovigilance network. Screening in clinical toxicology laboratories is not widespread, since these molecules are not detected by the standard screening tests, so that there is probably an under-estimation of the use of these new drugs. The legislation on these substances changes regularly, with more and more countries classifying them as "narcotics" or illegal psychotropic drugs so as to restrict their use, applying a generic classification when possible.

Legal highs: staying on top of the flood of novel psychoactive substances

There has been growing clinical, public, and media awareness and concern about the availability and potential harmfulness of so-called 'legal highs', which are more appropriately called new or novel psychoactive substances (NPS). A cat-and-mouse process has emerged wherein unknown chemists and laboratories are producing new, and as yet nonproscribed, compounds for human consumption; and as soon as they are banned, which they inevitably are, slightly modified analogues are produced to circumvent new laws. This rapidly changing environment, 81 new substances were identified in 2013 alone, has led to confusion for clinicians, psychopharmacologists, and the public at large. Our difficulties in keeping up with the process has had a two-fold negative effect: the danger of ignoring what is confusing; and the problem that some of the newer synthesized compounds appear ever more potent. This review aims to circumscribe a quick moving and growing field, and to categorize NPS into five major groups based upon their 'parent' compounds: stimulants similar to cocaine, amphetamines and ecstasy; cannabinoids; benzodiazepine based drugs; dissociatives similar to ketamine and phencyclidine (PCP); and those modelled after classic hallucinogens such as LSD and psilocybin. Pharmacodynamic actions, subjective and physical effects, harmfulness, risk of dependency and, where appropriate, putative clinical potentials are described for each class. Clinicians might encounter NPS in various ways: anecdotal reportage; acute intoxication; as part of a substance misuse profile; and as a precipitant or perpetuating factor for longer-term physical and psychological ill health. Current data are overall limited, and much of our knowledge and treatment strategies are based upon those of the 'parent' compound. There is a critical need for more research in this field, and for professionals to make themselves more aware of this growing issue and how it might affect those we see clinically and try to help: a brave new world of so-called 'psychonauts' consuming NPS will also need informed 'psychotherapeutonauts'. The paper should serve as a primer for clinicians and interested readers, as well as provide a framework into which to place the new substances that will inevitably be synthesized in the future.

"Legal Highs"--An Emerging Epidemic of Novel Psychoactive Substances

During the last decade, there has been an increase in the availability and use of novel psychoactive substances (NPS), also known as "legal highs," across the world. They include a wide range of products, from natural plant-originated substances to synthetic compounds, that can be purchased both online and from high street retailers. "Legal highs" mimic psychoactive effects of illicit drugs of abuse. However, they are claimed to consist of compounds that are legal to sell, possess, and use, often labeled as "not for human consumption" to circumvent drug abuse legislation. Based on the spectrum of their actions on cognitive processes, mood, and behavior, "legal highs" can be classified into four basis categories: amphetamine- and ecstasy-like stimulants, synthetic cannabinoids (SCs), hallucinogenic/dissociative, and opioid-like compounds. NPS may, however, exhibit a combination of these actions due to their designed chemical structure. Although the prevalence and pattern of NPS use differ between various countries, the most popular groups are SCs and psychostimulants, described in this chapter. Currently, there is limited information available on the potential acute toxicity (harms) associated with the use of these substances. However, the number of intoxicated people presenting with emergencies is constantly increasing, providing evidence that negative health and social consequences may indeed seriously affect recreational and chronic users.

Novel psychoactive substances of interest for psychiatry

Novel psychoactive substances include synthetic cannabinoids, cathinone derivatives, psychedelic phenethylamines, novel stimulants, synthetic opioids, tryptamine derivatives, phencyclidine-like dissociatives, piperazines, GABA-A/B receptor agonists, a range of prescribed medications, psychoactive plants/herbs, and a large series of performance and image enhancing drugs. Users are typically attracted by these substances due to their intense psychoactive effects and likely lack of detection in routine drug screenings. This paper aims at providing psychiatrists with updated knowledge of the clinical pharmacology and psychopathological consequences of the use of these substances. Indeed, these drugs act on a range of neurotransmitter pathways/receptors whose imbalance has been associated with psychopathological conditions, including dopamine, cannabinoid CB1, GABA-A/B, 5-HT2A, glutamate, and k opioid receptors. An overall approach in terms of clinical management is briefly discussed.

A 3-year review of new psychoactive substances in casework

Following the initial popularity of mephedrone (4-methylmethcathinone) there has been a stream of new "recreational drugs" entering the global market. The lack of clinical studies on the effects and toxicity of these drugs has made interpretation of toxicological findings difficult. In an attempt to assist in a better understanding of the extent of their use and the fatalities that have been linked to these compounds we present our collated findings in post-mortem and criminal casework where these have been detected and/or implicated. Between January 2010 and December 2012 we have detected new psychoactive substances (NPS) in 203 cases, with 120 cases in 2012 alone. The drugs detected in in life or post-mortem blood and urine are, in order of decreasing frequency; mephedrone, 4-methylethcathinone, BZP, MDPV, TFMPP, methoxetamine, 4-fluoromethcathinone, 4-methylamphetamine, PMA, methylone, PMMA, naphyrone, alpha-methyltryptamine, butylone, MDAI, desoxypipradrol, D2PM, MPA, synthetic cannabinoids, 2-AI, 5-IAI, 5-MeODALT, MDPBP, 5/6-APB, pentedrone and pentylone. Other drugs or alcohol were detected in 84% of the cases including other NPS and in fatalities it should be noted that alternative causes of death (including mechanical suicide, accidental death and non-psychoactive drug overdose) accounted for the majority. Related to this was that of all fatalities involving cathinones, 41% of these were hangings or other mechanical suicides, this was a higher proportion than seen with other drugs found in such cases. The presence of multiple NPS and/or other stimulants was a particular feature in various cases, however, of the drug deaths only 7% solely involved NPS. Across all case types and including some cases investigated in 2013, NPS concentrations showed a wide range but these and selected cases are presented to assist toxicological interpretation in future cases.

Behavioral and neurochemical pharmacology of six psychoactive substituted phenethylamines: mouse locomotion, rat drug discrimination and in vitro receptor and transporter binding and function

RATIONALE

Psychoactive-substituted phenethylamines 2,5-dimethoxy-4-chlorophenethylamine (2C-C); 2,5-dimethoxy-4-methylphenethylamine (2C-D); 2,5-dimethoxy-4-ethylphenethylamine (2C-E); 2,5-dimethoxy-4-iodophenethylamine (2C-I); 2,5-dimethoxy-4-ethylthiophenethylamine (2C-T-2); and 2,5-dimethoxy-4-chloroamphetamine (DOC) are used recreationally and may have deleterious side effects.

OBJECTIVES

This study compares the behavioral effects and the mechanisms of action of these substituted phenethylamines with those of hallucinogens and a stimulant.

METHODS

The effects of these compounds on mouse locomotor activity and in rats trained to discriminate dimethyltryptamine, (-)-DOM, (+)-LSD, (±)-MDMA, and S(+)-methamphetamine were assessed. Binding and functional activity of the phenethylamines at 5-HT1A, 5-HT2A, 5-HT2C receptors and monoamine transporters were assessed using cells heterologously expressing these proteins.

RESULTS

The phenethylamines depressed mouse locomotor activity, although 2C-D and 2C-E stimulated activity at low doses. The phenethylamines except 2C-T-2 fully substituted for at least one hallucinogenic training compound, but none fully substituted for (+)-methamphetamine. At 5-HT1A receptors, only 2C-T-2 and 2C-I were partial-to-full very low potency agonists. In 5-HT2A arachidonic acid release assays, the phenethylamines were partial to full agonists except 2C-I which was an antagonist. All compounds were full agonists at 5-HT2A and 5-HT2C receptor inositol phosphate assays. Only 2C-I had moderate affinity for, and very low potency at, the serotonin transporter.

CONCLUSIONS

The discriminative stimulus effects of 2C-C, 2C-D, 2C-E, 2C-I, and DOC were similar to those of several hallucinogens, but not methamphetamine. Additionally, the substituted phenethylamines were full agonists at 5-HT2A and 5-HT2C receptors, but for 2C-T-2, this was not sufficient to produce hallucinogen-like discriminative stimulus effects. Additionally, the 5-HT2A inositol phosphate pathway may be important in 2C-I's psychoactive properties.

Cross-reactivity of designer drugs, including cathinone derivatives, in commercial enzyme-linked immunosorbent assays

Since the introduction of synthetic heroin, designer drugs have been increasing in prevalence in the United States drug market over the past few decades. Recently, 'legal highs' sold as 'bath salts' have become a household term for one such class of designer drugs. While a number of federal and state bans have been enacted, the abuse of these designer drugs still continues. Few assays have been developed for the comprehensive detection of such compounds, so it is important to investigate how they may or may not react in presumptive screens, i.e. pre-existing commercial immunoassays. In this experiment, 16 different ELISA reagents were evaluated to determine the cross-reactivity of 30 designer drugs, including 24 phenylethylamines (including 8 cathinone derivatives), 3 piperazines, and 3 tryptamines. Cross-reactivity towards most drugs was <4% in assays targeting amphetamine or methamphetamine. Compounds such as MDA, MDMA, ethylamphetamine, and α-methyltryptamine demonstrated cross-reactivities in the range of 30-250%, but data were consistent with both manufacturer's inserts and published literature. When tested against the Randox Mephedrone/Methcathinone kit, cathinone derivatives demonstrated cross-reactivity at concentrations as low as 150 ng/ml. Since this same reagent did not cross-react with other amphetamine-like compounds, it opens the possibility to screen post-mortem specimens without the interference of putrefactive amines. All other assays demonstrated essentially no cross-reactivity towards any of the analytes evaluated. Given these results, a great need exists for more broad-range screening techniques to be applied when analyzing biological specimens by immunoassays for drugs of abuse, specifically the more recent designer drugs.