MT-45, a new psychoactive substance associated with hearing loss and unconsciousness

The Effects of Substance Misuse on Auditory and Vestibular Function: A Systematic Review

BACKGROUND

Chronic substance misuse is an ongoing and significant public health concern. Among a myriad of health complications that can occur, substance misuse potentially causes ototoxic effects. Case reports, retrospective chart data, and a few cohort studies suggest that certain prescription opioids and illicit drugs can have either temporary or permanent effects on auditory and/or vestibular function. Given the steady rise of people with a substance-use disorder (SUD), it is of growing importance that audiologists and otolaryngologists have an insight into the potential ototoxic effects of substance misuse.

OBJECTIVES

A systematic review was conducted to (1) synthesize the literature on the illicit drugs, prescription opioids, and alcohol misuse on the auditory and vestibular systems, (2) highlight common hearing and vestibular impairments for each substance class, and (3) discuss the limitations of the literature, the potential mechanisms, and clinical implications for clinicians who may encounter patients with hearing or vestibular loss related to substance misuse, and describe opportunities for further study.

DESIGN

Systematic searches were performed via PubMed, Scopus, and Google Scholar, and the final updated search was conducted through March 30, 2022. Inclusion criteria included peer-reviewed articles, regardless of study design, from inception until the present that included adults with chronic substance misuse and hearing and/or vestibular complaints. Articles that focused on the acute effects of substances in healthy people, ototoxicity from already known ototoxic medications, the relationship between hearing loss and development of a SUD, articles not available in English, animal work, and duplicates were excluded. Information on the population (adults), outcomes (hearing and/or vestibular data results), and study design (e.g., case report, cohort) were extracted. A meta-analysis could not be performed because more than 60% of the studies were single-case reports or small cohort.

RESULTS

The full text of 67 studies that met the eligibility criteria were selected for the review. Overall, 21 studies reported associations between HL/VL related to illicit drug misuse, 28 studies reported HL/VL from prescription opioids, and 20 studies reported HL/VL related to chronic alcohol misuse (2 studies spanned more than one category). Synthesis of the findings suggested that the misuse and/or overdose of amphetamines and cocaine was associated with sudden, bilateral, and temporary HL, whereas HL from the combination of a stimulant and an opioid often presented with greater HL in the mid-frequency range. Reports of temporary vertigo or imbalance were mainly associated with illicit drugs. HL associated with misuse of prescription opioids was typically sudden or rapidly progressive, bilateral, moderately severe to profound, and in almost all cases permanent. The misuse of prescription opioids occasionally resulted in peripheral VL, especially when the opioid misuse was long term. Chronic alcohol misuse tended to associate with high-frequency sudden or progressive sensorineural hearing loss, or retrocochlear dysfunction, and a high occurrence of central vestibular dysfunction and imbalance.

CONCLUSIONS

Overall, chronic substance misuse associates with potential ototoxic effects, resulting in temporary or permanent hearing and/or vestibular dysfunction. However, there are notable limitations to the evidence from the extant literature including a lack of objective test measures used to describe hearing or vestibular effects associated with substance misuse, small study sample sizes, reliance on case studies, lack of controlling for confounders related to health, age, sex, and other substance-use factors. Future large-scale studies with prospective study designs are needed to further ascertain the role and risk factors of substance misuse on auditory and vestibular function and to further clinical management practices.

Non-fentanyl new synthetic opioids - An update

BACKGROUND

New synthetic opioids (NSO) constitute one of the fastest-growing group of New Psychoactive Substances, which emerged on the illicit drug marker in the second half of 2000's. The most popular and the largest NSO subgroup are high potency fentanyl and its analogs. Subsequent to core-structure scheduling of fentanyl-related substances many opioids with different chemical structures are now emerging on the illicit drug market, rendering the landscape highly complex and dynamic.

METHODS

PubMed, Scopus and Google Scholar were searched for appropriate articles up to December 2022. Moreover, a search for reports was conducted on Institutional websites to identify documentation published by World Health Organization, United Nations Office on Drugs and Crime, United States Drug Enforcement Administration, and European Monitoring Centre for Drugs and Drug Addiction. Only articles or reports written in English were selected.

RESULTS

Non-fentanyl derived synthetic opioids, i.e., 2-benzylbenzimidazoles (nitazenes), brorphine, U-compounds, AH-7921, MT-45 and related compounds are characterized, describing them in terms of available forms, pharmacology, metabolism as well as their toxic effects. Sample procedures and analytical techniques available for detection and quantification of these compounds in biological matrices are also presented. Finally, as overdoses involving highly potent NSO may be difficult to reverse, the effectiveness of naloxone as a rescue agent in NSO overdose is discussed.

CONCLUSIONS

Current review presents key information on non-fentanyl derived NSO. Access to upto-date data on substances of abuse is of great importance for clinicians, public health authorities and professionals performing analyses of biological samples.

Revealing the structure and mechanisms of action of a synthetic opioid with model biological membranes at the air-water interface

Synthetic opioids such as piperazine derivative called MT-45 interact with opioid receptors in a manner similar to morphine leading to euphoria, a sense of relaxation and pain relief and are commonly used as substituents of natural opioids. In this study we show the changes in the surface properties of nasal mucosa and intestinal epithelial model cell membranes formed at the air - water interface using Langmuir technique upon the exposure to MT-45. Both membranes constitute the first barrier to absorb this substance into the human body. The presence of the piperazine derivative affects the organization of both DPPC and ternary DMPC:DMPE:DMPS monolayers treated as simple models of nasal mucosa and intestinal cell membranes, respectively. This novel psychoactive substance (NPS) leads to the fluidization of the model layers, which may indicate their increased permeability. MT-45 has a greater influence on the ternary monolayers characteristic of the intestinal epithelial cells than nasal mucosa. It might be attributed to the increased attractive interactions between the components of the ternary layer, which in turn increase the interactions with a synthetic opioid. Additionally, the crystal structures of MT-45 determined by single-crystal and powder X-ray diffraction methods allowed us to both provide useful data for facilitating the identification of synthetic opioids as well as to attribute the effect of MT-45 to the ionic interactions between protonated nitrogen atoms and negatively charged parts of the polar heads of the lipids.

Proliferation of Novel Synthetic Opioids in Postmortem Investigations After Core-Structure Scheduling for Fentanyl-Related Substances

ABSTRACT

New generations of novel synthetic opioids (NSOs) have emerged to fill a void in the illicit drug markets left by the decline in popularity of fentanyl analogs subsequent to core-structure scheduling of fentanyl-related substances in the United States and China. These new opioids include members of the 2-benzyl benzimidazole (eg, isotonitazene, metonitazene, N -pyrrolidino etonitazene, protonitazene, etodesnitazene), benzimidazolone (eg, brorphine), and cinnamylpiperazine (eg, AP-238, 2-methyl AP-237) subclasses. Novel synthetic opioids continue to be detected in opioid-related fatal overdoses, demonstrating the harms associated with exposure to these drugs. Between January 2020 and December 2021, 384 casework blood samples were reported by our laboratory to contain 1 or more of the prior listed 8 NSOs. Isotonitazene (n = 144), metonitazene (n = 122), and brorphine (n = 91) were the 3 most prevalent substances, with positivity for isotonitazene and brorphine peaking just before the announcement of emergency scheduling. These NSOs have been documented as significant drivers of drug mortality, and this case series described here highlights the challenges medical examiners and coroners face in staying current with emerging drugs. Challenges include regional differences, rapid turnover, short lifecycles, variable toxicology testing, and difficulty in assessing individual drug toxicity in polydrug cases.

Characteristics of fatal 'novel' synthetic opioid toxicity in Australia

BACKGROUND

Aims: To determine 1. The characteristics of all recorded cases of fatal drug poisoning involving novel synthetic opioids (NSOs) in Australia; 2. The toxicology of cases; and 3. The major autopsy findings.

METHODS

Review of all fatal poisonings related to NSOs in Australia 2000-2021 identified in the National Coronial Information System.

RESULTS

Thirty-one cases were identified, 96.8% due to unintentional drug toxicity. The mean age was 31.9 years and 87.1% were male. Only six were aged over forty. A history of substance use problems was documented in 80.6% and 58.1% had a history of injecting drug use. In 32.3% the final route of administration of a NSO was by non-injecting routes of administration. Ten NSOs were identified. Fentanyl analogues were present in 67.2%, most commonly furanylfenatyl (19.4%). Other NSO types were present in 39.7%, most commonly U-47700 (35.5%). Substances other than NSOs were present in 90.3%, most commonly benzodiazepines (67.7%) and other opioids (51.6%). A CNS depressant in addition to NSOs was present in 90.3%, and a new psychoactive substance other than a NSO in 25.8%. Pulmonary oedema was diagnosed in 82.6%, aspiration of vomitus in 30.4%, and acute bronchopneumonia in 17.4%.

CONCLUSIONS

Ten NSOs were identified. Case characteristics suggest a younger cohort whose profile is more typical of use of other NPS than of the established opioids. A large proportion used NSOs by non-injecting routes of administration.

Hearing and Vestibular Loss with Misuse of Opioids and Illicit Drugs: A Review of the Literature

BACKGROUND

The purpose of this review was to summarize the literature regarding the effects of opioids and illicit drugs on the auditory and vestibular systems.

METHODS

Data were sourced from published papers reporting hearing loss (HL) and/or vestibular loss (VL) following misuse or overdose of opioids or illicit drugs. Most papers consisted of retrospective single-case reports, with few retrospective reviews or prospective cohort studies. Search terms included variations of HL, VL, opioids, and illicit drugs. Search results yielded 51 articles published between 1976 and 2021. A total of 44 articles were reviewed after excluding studies that were not available in English (n = 3), only described acute effects in healthy cohorts (n = 3) or only described general health aspects in a group on methadone maintenance (n = 1).

RESULTS

Sixteen studies reported ototoxicity from illicit drugs, 27 from prescription opioids, and 1 was unspecified. This review shows that HL associated with amphetamines and cocaine was typically sudden, bilateral, and temporary. HL from cocaine/crack and heroin often presented with greatest losses in the mid-frequency range. HL associated with opioids was typically sudden, bilateral, moderately severe to profound, and in most cases permanent. The literature is sparse regarding VL from illicit drugs and opioids.

CONCLUSION

Practitioners who see patients for sudden or rapidly progressive HL or VL with no apparent cause should inquire about misuse of illicit drugs and opioids, particularly when the HL does not respond to steroid treatment.

Synthetic opioids: a review and clinical update

The term 'opioids' refers to both the natural compounds ('opiates') which are extracted from the opium poppy plant (Papaver somniferum) and their semi-synthetic and synthetic derivatives. They all possess relatively similar biochemical profiles and interact with the opioid receptors within the human body to produce a wide range of physiological effects. They have historically been used for medicinal purposes, their analgesic and sedative effects, and in the management of chronic and severe pain. They have also been used for non-medicinal and recreational purposes to produce feelings of relaxation, euphoria and well-being. Over the last decade, the emergence of an illegal market in new synthetic opioids has become a major global public health issue, associated with a substantial increase in unintentional overdoses and drug-related deaths. Synthetic opioids include fentanyl, its analogues and emerging non-fentanyl opioids. Their popularity relates to changes in criminal markets, pricing, potency, availability compared to classic opioids, ease of transport and use, rapid effect and lack of detection by conventional testing technologies. This article expands on our previous review on new psychoactive substances. We now provide a more in-depth review on synthetic opioids and explore the current challenges faced by people who use drugs, healthcare professionals, and global public health systems.

Blood concentrations of new synthetic opioids

PURPOSE

Over the last decade, there has been a significant growth in the market and number of new psychoactive substances (NPS). One of the NPS groups that has grown rapidly in recent years, bringing a new set of problems, consists of new synthetic opioids. The extreme potency of these compounds poses a high risk of acute poisoning, as an overdose can cause respiratory depression. Most of the information regarding human pharmacokinetics of new opioids is based on toxicological case reports and the data on concentrations of new opioids in human blood are scarce. The interpretation of results usually requires a comparison to previously published cases; therefore, a referenced compilation of previously published concentration data would be useful.

METHODS

The data were collected by searching the PubMed and Scopus databases and by using the Google search engine. All the available data from articles and reports that measured new opioid concentrations in plasma, serum, or whole blood were included in the data analysis.

RESULTS

The presented tables list the observed concentrations in fatal and nonfatal cases involving 37 novel synthetic opioids.

CONCLUSIONS

Blood levels of new opioids are extremely difficult to interpret. Low blood concentrations of these substances do not rule out acute poisoning as their high potency creates a risk of respiratory depression even at low doses. Opioid tolerance, frequent presence of other drugs, and additional diseases make it impossible to define concentration ranges, especially the minimum fatal concentrations. This report provides quick access to the source articles quantifying novel synthetic opioids.

Clinical Pharmacology, Toxicity, and Abuse Potential of Opioids

Opioids were the most common drug class resulting in overdose deaths in the United States in 2019. Widespread clinical use of prescription opioids for moderate to severe pain contributed to the ongoing opioid epidemic with the subsequent emergence of fentanyl-laced heroin. More potent analogues of fentanyl and structurally diverse opioid receptor agonists such as AH-7921 and MT-45 are fueling an increasingly diverse illicit opioid supply. Overdose from synthetic opioids with high binding affinities may not respond to a typical naloxone dose, thereby rendering autoinjectors less effective, requiring higher antagonist doses or resulting in a confusing clinical picture for health care providers. Nonscheduled opioid drugs such as loperamide and dextromethorphan are associated with dependence and risk of overdose as easier access makes them attractive to opioid users. Despite a common opioid-mediated pathway, several opioids present with unique pharmacodynamic properties leading to acute toxicity and dependence development. Pharmacokinetic considerations involve half-life of the parent opioid and its metabolites as well as resulting toxicity, as is established for tramadol, codeine, and oxycodone. Pharmacokinetic considerations, toxicities, and treatment approaches for notable opioids are reviewed.

Drugs of abuse and ocular effects

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

Report on a New Opioid NPS: Chemical and In Vitro Functional Characterization of a Structural Isomer of the MT-45 Derivative Diphenpipenol

In this paper, the identification and full characterization of a novel non-fentanyl opioid sourced online, which is a member of the 1-substituted-4-(1,2-diphenylethyl)piperazine derivatives related to MT-45, is reported. The sample was sold under the name "diphenpipenol," (3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]-2-phenylethyl]phenol), although extensive NMR analysis showed that the product obtained was actually a diphenpipenol structural isomer, (2-[4-(2-methoxyphenyl)piperazin-1-yl]-1,2-diphenylethanol). Liquid chromatography time-of-flight mass spectrometry identified an exact mass for the protonated molecule of m/z 389.2264, with two prominent fragment ions (m/z 91.0567 and 150.0937), which were not reported in earlier literature describing MT-45 derivatives. The chemical characterization was finalized by gas chromatography-mass spectrometry, high-performance liquid chromatography diode array detector and Fourier-transform infrared spectroscopy analyses. This product is a clear example of the trend that new non-fentanyl opioids are reappearing on the recreational drug market to escape the recent changes in (inter)national legislation concerning fentanyl analogues. Although in this particular case, the product's potency and efficacy were relatively low, other new non-fentanyl opioids might possess stronger potencies and therefore pose greater health risks for ignorant users. The fact that the product was sold under the wrong name further demonstrates the well-known problematic issue of a mismatch between the adverted and true identity, confirming the irregularities of the online new psychoactive substances market.

Pharmacotherapy of Patients Taking New Psychoactive Substances: A Systematic Review and Analysis of Case Reports

Background: In recent years, an increase in the frequency of hospitalizations of patients taking newer and newer psychoactive substances has been observed around the world. Each year, authors publish case reports of patients who consumed previously unknown NPS. Most publications of this type concern the period between 2014 and 2016. However, no publication systematically reviews the pharmacotherapy used in these cases. This study aims to review the case reports of patients taking NPS published between 2010 and 2019, as well as analyzing the pharmacotherapy used. Methods: We searched the Thomson (Web of Knowledge), PubMed/Medline, Science Direct, Scopus and Google Scholar databases. The search was performed using all possible combinations of the term "case report" describing the use of NPS, also referred to as designer medications, internet medications, research chemicals and herbal highs. Results: We analyzed 51 case reports on the intake of various types of NPS. Most of them (p < 0.001) concerned the use of synthetic cannabinoids (41.2%) and cathinones (31.4%). The pharmacotherapy applied primarily (p < 0.001) consisted of administering benzodiazepines to patients (62.7%), most of whom took only this group of medications (25.5%), followed by groups receiving benzodiazepines combined with neuroleptics (15.7%) and muscle relaxants (11.8%). Opioids were administered primarily to patients taking synthetic opioids (p < 0.001). Of the 5 cases of deaths from NPS reported in the literature, three relate specifically to the synthetic opioid MT-45. The later the time period, the more medications patients were administered (p = 0.02). Conclusion: In the pharmacotherapy for NPS poisoning, one should focus primarily on combating psychomotor agitation.

Activation of μ-opioid receptors by MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) and its fluorinated derivatives

BACKGROUND AND PURPOSE

A fluorinated derivative (2F-MT-45) of the synthetic μ-opioid receptor agonist MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) was recently identified in a seized illicit tablet. While MT-45 is a Class A drug, banned in a number of countries, nothing is known about the pharmacology of 2F-MT-45. This study compares the pharmacology of MT-45, its fluorinated derivatives and two of its metabolites.

EXPERIMENTAL APPROACH

We used a β-arrestin2 recruitment assay in CHO cells stably expressing μ receptors to quantify the apparent potencies and efficacies of known (MT-45, morphine, fentanyl and DAMGO) and potential agonists. In addition, the GloSensor protein was transiently expressed to quantify changes in cAMP levels. We measured Ca²⁺ to investigate whether MT-45 and its metabolites have effects on GluN1/N2A NMDA receptors stably expressed in Ltk- cells.

KEY RESULTS

The fluorinated MT-45 derivatives have higher apparent potencies (2F-MT-45: 42 nM) than MT-45 (1.3 μM) for inhibition of cAMP accumulation and β-arrestin2 recruitment (2F-MT-45: 196 nM; MT-45: 23.1 μM). While MT-45 and 2F-MT-45 are poor recruiters of β-arrestin2, they have similar efficacies for reducing cAMP levels as DAMGO. Two MT-45 metabolites displayed negligible potencies as μ receptor agonists, but one, 1,2-diphenylethylpiperazine, inhibited the NMDA receptor with an IC₅₀ of 29 μM.

CONCLUSION AND IMPLICATIONS

Fluorinated derivatives of MT-45 are potent μ receptor agonists and this may pose a danger to illicit opioid users. Inhibition of NMDA receptors by a metabolite of MT-45 may contribute to the reported dissociative effects.

In vitro and in vivo pharmacological characterization of the synthetic opioid MT-45

MT-45 is a synthetic opioid that was developed in the 1970s as an analgesic compound. However, in recent years MT-45 has been associated with multiple deaths in Europe and has been included in the class of novel psychoactive substances known as novel synthetic opioids (NSOs). Little is known about the pharmaco-toxicological effects of MT-45. Therefore, we used a dynamic mass redistribution (DMR) assay to investigate the pharmacodynamic profile of this NSO in vitro compared with morphine. We then used in vivo studies to investigate the effect of the acute systemic administration of MT-45 (0.01-15 mg/kg i.p.) on motor and sensorimotor (visual, acoustic and tactile) responses, mechanical and thermal analgesia, muscle strength and body temperature in CD-1 male mice. Higher doses of MT-45 (6-30 mg/kg i.p.) were used to investigate cardiorespiratory changes (heart rate, respiratory rate, SpO₂ saturation and pulse distention). All effects of MT-45 were compared with those of morphine. In vitro DMR assay results demonstrated that at human recombinant opioid receptors MT-45 behaves as a potent selective mu agonist with a slightly higher efficacy than morphine. In vivo results showed that MT-45 progressively induces tail elevation at the lowest dose tested (0.01 mg/kg), increased mechanical and thermal antinociception (starting from 1 to 6 mg/kg), decreased visual sensorimotor responses (starting from 3 to 6 mg/kg) and reduced tactile responses, modulated motor performance and induced muscle rigidity at higher doses (15 mg/kg). In addition, at higher doses (15-30 mg/kg) MT-45 impaired the cardiorespiratory functions. All effects were prevented by the administration of the opioid receptor antagonist naloxone. These findings reveal the risks associated with the ingestion of opioids and the importance of studying these drugs and undertaking more clinical studies of the current molecules to better understand possible therapeutic interventions in the case of toxicity.

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

Background

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

Methods and findings

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

Conclusions

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

Designer drugs: mechanism of action and adverse effects

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

Novel synthetic opioids - toxicological aspects and analysis

Over the past few years, there has been an emerging number of new psychoactive drugs. These drugs are frequently mentioned as "legal highs", "herbal highs", "bath salts" and "research chemicals". They are mostly sold and advertised on online forums and on the dark web. The emerging new psychoactive substances are designed to mimic the effects of psychoactive groups, which are often abused drugs. Novel synthetic opioids are a new trend in this context and represent an alarming threat to public health. Given the wide number of fatalities related to these compounds reported within the last few years, it is an important task to accurately identify these compounds in biologic matrices in order to administer an effective treatment and reverse the respiratory depression caused by opioid related substances. Clinicians dealing with fentanyl intoxication cases should consider that it could, in fact, be a fentanyl analogue. For this reason, it is a helpful recommendation to include synthetic opioids in the routine toxicological screening procedures, including analysis in alternative matrices, if available, to investigate poly-drug use and possible tolerance to opioids. To address this public health problem, better international collaboration, effective legislation, effective investigation, control of suspicious "research chemicals" online forums and continuous community alertness are required. This article aims to review diverse reported fatalities associated with new synthetic opioids describing them in terms of pharmacology, metabolism, posology, available forms, as well as their toxic effects, highlighting the sample procedures and analytical techniques available for their detection and quantification in biological matrices.

Epidemiology of NPS Based Confirmed Overdose Cases: The STRIDA Project

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

The Fentanyl Epidemic and Evolution of Fentanyl Analogs in the United States and the European Union

BACKGROUND

Since 2013, an unprecedented surge in fentanyl overdose deaths has been caused by heroin laced with illicitly produced fentanyl and/or fentanyl analogs (FAs) sold as heroin. The US Drug Enforcement Agency's National Forensic Laboratory Information System reported a &gt;300% increase in fentanyl encounters from 4697 in 2014 to 14440 in 2015. In 2015, the CDC reported 9580 deaths caused by synthetic opioids, primarily fentanyl, a 72% increase from 2014. The European Monitoring Centre for Drugs and Drug Addiction has also encountered several new FAs in the heroin supply. Counterfeit pharmaceuticals containing mixtures of fentanyl and FAs continue to be a poorly recognized worldwide problem despite the WHO classifying several FAs as a serious threat to public health.

CONTENT

This review covers the epidemiology of fentanyl abuse and discusses the clinical practice implications of widespread fentanyl abuse. It includes a historical perspective on the illicit FAs that have appeared in the US and European Union and reviews the methods available to identify FAs and emerging technologies useful for identifying previously undescribed analogs. A compilation of structural and mass spectral data on FAs reported thus far is provided.

SUMMARY

Fentanyl and FAs have evolved into a global public health threat. It is important to understand the analytical, clinical, and regulatory efforts underway to assist communities affected by the current fentanyl epidemic.

Non-Medical Use of Novel Synthetic Opioids: A New Challenge to Public Health

Background: In the last decade there has been a progressive increase in the use of new psychoactive substances (NPSs) that are not yet under international control. In particular, novel synthetic opioids (NSOs) have reappeared on the recreational drug market in the last few years. As a result, the use of NSOs has increased rapidly. This poses an emerging and demanding challenge to public health. Aim: To raise awareness among clinicians and other professionals about NPSs, especially NSOs, to summarize current knowledge about pharmacological properties, forms of NSO on the market, pattern of use, effects and consequences of use. Methods: An electronic search was carried out on the Medline/PubMed and Google Scholar databases to find selected search terms. Results: Some NPSs are already controlled, while others can be legally sold directly on the drug market (mainly via internet, less so by drug dealers) or be used as precursors for the synthesis of other designer drugs that mimic the psychoactive effects of controlled substances. Potential side-effects of NSOs include miosis, sedation, respiratory depression, hypothermia, inhibition of gastrointestinal propulsion, death (from opioid overdose). Conclusions: The severity of the opioid crisis has intensified with the introduction of highly potent NSOs on the drug market. As long as addicts are dying from overdose or similar causes, there is something more constructive to do than waiting for addicts to overdose on heroin at a place located near a remedy, as if to say, within reach of naloxone.

The search for the "next" euphoric non-fentanil novel synthetic opioids on the illicit drugs market: current status and horizon scanning

PURPOSE

A detailed review on the chemistry and pharmacology of non-fentanil novel synthetic opioid receptor agonists, particularly N-substituted benzamides and acetamides (known colloquially as U-drugs) and 4-aminocyclohexanols, developed at the Upjohn Company in the 1970s and 1980s is presented.

METHOD

Peer-reviewed literature, patents, professional literature, data from international early warning systems and drug user fora discussion threads have been used to track their emergence as substances of abuse.

RESULTS

In terms of impact on drug markets, prevalence and harm, the most significant compound of this class to date has been U-47700 (trans-3,4-dichloro-N-[2-(dimethylamino)cyclohexyl]-N-methylbenzamide), reported by users to give short-lasting euphoric effects and a desire to re-dose. Since U-47700 was internationally controlled in 2017, a range of related compounds with similar chemical structures, adapted from the original patented compounds, have appeared on the illicit drugs market. Interest in a structurally unrelated opioid developed by the Upjohn Company and now known as BDPC/bromadol appears to be increasing and should be closely monitored.

CONCLUSIONS

International early warning systems are an essential part of tracking emerging psychoactive substances and allow responsive action to be taken to facilitate the gathering of relevant data for detailed risk assessments. Pre-emptive research on the most likely compounds to emerge next, so providing drug metabolism and pharmacokinetic data to ensure that new substances are detected early in toxicological samples is recommended. As these compounds are chiral compounds and stereochemistry has a large effect on their potency, it is recommended that detection methods consider the determination of configuration.

Novel Synthetic Opioids: The Pathologist's Point of View

Background: New Psychoactive Substances (NPS) constitute a broad range of hundreds of natural and synthetic drugs, including synthetic opioids, synthetic cannabinoids, synthetic cathinones, and other NPS classes, which were not controlled from 1961 to 1971 by the United Nations drug control conventions. Among these, synthetic opioids represent a major threat to public health. Methods: A literature search was carried out using public databases (such as PubMed, Google Scholar, and Scopus) to survey fentanyl-, fentanyl analogs-, and other synthetic opioid-related deaths. Keywords including “fentanyl”, “fentanyl analogs”, “death”, “overdose”, “intoxication”, “synthetic opioids”, “Novel Psychoactive Substances”, “MT-45”, “AH-7921”, and “U-47700” were used for the inquiry. Results: From our literature examination, we inferred the frequent implication of fentanyls and synthetic opioids in side effects, which primarily affected the central nervous system and the cardiovascular and pulmonary systems. The data showed a great variety of substances and lethal concentrations. Multidrug-related deaths appeared very common, in most reported cases. Conclusions: The investigation of the contribution of novel synthetic opioid intoxication to death should be based on a multidisciplinary approach aimed at framing each case and directing the investigation towards targeted toxicological analyses.

Pharmacotoxicology of Non-fentanyl Derived New Synthetic Opioids

A class of opioid agonists not structurally related to fentanyl, derived from research publications of pharmaceutical companies or patents within the United States and abroad are contributing to the current opioid epidemic. Novel synthetic opioids (NSOs) created to circumvent drug control laws such as U-47700, U-49900, AH-7921, or MT-45 have no recognized therapeutic use, are clandestinely manufactured and sold on conventional or dark web. We herein provide a review of the pharmacological properties available on most of these substances trying to provide a better knowledge on these compounds, particularly with respect to toxicity and dangerous adverse effects in users. Indeed, these NSOs share not only a great potency of action and receptor affinity with respect to natural or synthetic opiates (e.g., morphine, heroin, and methadone) but also a non-negligible toxicity leading to intoxications and fatalities, posing a serious harm to public health and society.

Fatalities caused by novel opioids: a review

Drugs related to morphine represent not only large range of important therapeutic applications for the relief of moderate to severe pain but also give rise to a relatively large series of novel opioids that mimic the action of this naturally occurring analgesic. Most of these are based on fentanyl structures that are much more potent, and dangerous, than fentanyl itself. This publication reviews reports of fatalities attributed to 15 novel opioids with the view to assessing mortality associated with their misuse as well as reviewing published analytical procedures that would be able to detect these and other novel opioids. These drugs include reports of deaths to acetylfentanyl, acrylfentanyl, butr(yl)fentanyl, carfentanil, 2- and 4-fluorofentanyls, 4-fluorobutyrfentanyl, 4-fluoroisobutyrfentanyl, furanylfentanyl, α- and 3-methylfentanyls, 4-methoxyfentanyl, ocfentanil, as well as AH-7921, U-47700 and MT-45. Most of these cases reporting a drug-caused death involved other drugs in addition to the opioid. No obvious minimum fatal concentration was discerned for any of the opioids for which details were provided, however, the more potent members required detection limits well under 1 ng/mL and often even well below 0.1 ng/mL requiring use of the most sensitive mass spectral detection procedures, particularly when screening specimens using a non-targeted mode. Four other novel opioids have been reported in admissions to hospitals include 4-chloroisobutryfentanyl, cyclopentylfentanyl and tetrahydrofuranfentanyl, all of which are likely to have the potential to cause death. It is also likely that other analogues will appear with time.

Chemical synthesis, characterisation and in vitro and in vivo metabolism of the synthetic opioid MT-45 and its newly identified fluorinated analogue 2F-MT-45 with metabolite confirmation in urine samples from known drug users

Purpose

The detection of a novel psychoactive substance, 2F-MT-45, a fluorinated analogue of the synthetic opioid MT-45, was reported in a single seized tablet. MT-45, 2F-, 3F- and 4F-MT-45 were synthesised and reference analytical data were reported. The in vitro and in vivo metabolisms of MT-45 and 2F-MT-45 were investigated.

Method

The reference standards and seized sample were characterised using nuclear magnetic resonance spectroscopy, ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry, gas chromatography-mass spectrometry, attenuated total reflectance-Fourier transform infrared spectroscopy and Raman spectroscopy. Presumptive tests were performed and physicochemical properties of the compounds determined. Metabolite identification studies using human liver microsomes, human hepatocytes, mouse hepatocytes and in vivo testing using mice were performed and identified MT-45 metabolites were confirmed in authentic human urine samples.

Results

Metabolic pathways identified for MT-45 and 2F-MT-45 were N-dealkylation, hydroxylation and subsequent glucuronidation. The major MT-45 metabolites identified in human in vitro studies and in authenticated human urine were phase I metabolites and should be incorporated as analytical targets to existing toxicological screening methods. Phase II glucuronidated metabolites were present in much lower proportions.

Conclusions

2F-MT-45 has been detected in a seized tablet for the first time. The metabolite identification data provide useful urinary metabolite targets for forensic and clinical testing for MT-45 and allows screening of urine for 2F-MT-45 and its major metabolites to determine its prevalence in case work.

Detectability of fentanyl and designer fentanyls in urine by 3 commercial fentanyl immunoassays

In recent times, structural variants of fentanyl (designer fentanyls) have appeared on the recreational drug market for new psychoactive substances (NPS). These potent opioids have caused harmful intoxications and increased opioid-related mortality in many countries. This work evaluated 3 commercial immunoassays for fentanyl screening in urine and investigated whether they are useful also for screening of designer fentanyls. The assays examined were the Thermo DRI® Fentanyl Enzyme Immunoassay, the ARK™ Fentanyl Assay homogeneous enzyme immunoassay, and the Immunalysis® Fentanyl Urine SEFRIA™ Drug Screening Kit. A liquid chromatography-high-resolution mass spectrometry method was used as reference. The DRI fentanyl immunoassay generated somewhat higher assay imprecision values (%CV) compared with the ARK™ and SEFRIA™ assays, but all assays showed %CV values acceptable for routine use. The 3 assays showed overall good detectability (33%-95% cross-reactivity) for blank urine samples spiked with acetylfentanyl, acrylfentanyl, butyrfentanyl, 4-chloroisobutyrfentanyl, 4-fluorobutyrfentanyl, 4-fluorofentanyl, 4-fluoroisobutyrfentnyl, isobutyrfentanyl, methoxyacetylfentanyl, or tetrahydrofuranfentanyl, whereas 4-methoxybutyrfentanyl (all assays) and 2-fluorofentanyl (DRI assay) showed low cross-reactivity. A good detectability of designer fentanyls was confirmed in urine samples from authentic acute intoxications. In conclusion, the present results demonstrate that the urinary fentanyl immunoassays are generally useful also for preliminary screening of fentanyl analogs sold as NPS. When the SEFRIA™ assay was applied for testing of 980 urine samples from patients treated for drug dependence in Sweden, only 1 sample was confirmed positive for fentanyl.

Synthetic Opioids

Opioid abuse has been a global menace for centuries, but the proliferation of synthetic opioids and their use within this current decade have created epidemic-level harms in some countries. According to the United Nations Office on Drugs and Crime, almost 12 million years were estimated loss of "healthy" life resulting in premature death and disability attributable to global opioid abuse just in 2015. Law enforcement and regulatory authorities have been particularly challenged abating the spread of synthetic opioids because soon after controlling the currently recognized abused opioids, their structures are tweaked, and new entities replace them. Drug racketeers have most often exploited the fentanyl phenylpiperidine structure in this regard, but non-fentanyl-like and classical morphinan-like structures have been pirated as well. A growing number of anecdotal reports identify respiratory depression induced by these newer synthetic opioids to be especially refractive to reversal by antagonists, with consequently high levels of lethality. This review examines three of these synthetic opioids representing three chemical classes (U-47700, MT-45, and acetylfentanyl) that have emerged to be of such menace that they have been brought under international control in recent years and addresses factors that could make synthetic opioids especially untreatable by opioid antagonists.

Bioanalytical Methods for New Psychoactive Substances

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

Identification of MT-45 Metabolites: In Silico Prediction, In Vitro Incubation with Rat Hepatocytes and In Vivo Confirmation

MT-45 is a synthetic opioid with a pharmacological activity comparable to morphine and it has been involved in intoxications and fatalities reported in Europe and in USA. It was recently subject to control measures, but to date the metabolic pathways of the substance are still unknown. Using rat hepatocytes and LC-HRMS, 14 novel Phase I and II MT-45 metabolites were identified, products of monohydroxylation, dihydroxylation and N-dealkylation; glucuronide conjugation of mono- and dihydroxylated metabolites also occurred. The detected metabolites were firstly predicted in silico, then incubation of the drug with rat hepatocytes was carried out and the obtained metabolites were identified by LC-HRMS, with retention times, mass shift between theoretical mass and observed mass (<5 ppm), peak abundance and fragmentation pattern. Hydroxylated MT-45 was found to be the major metabolite of MT-45 in vitro experiments. The presence of all metabolites was confirmed by in vivo experiments in urine samples of CD-1 male mice; in these samples hydroxy-MT-45-glucuronide and di-hydroxy-MT-45-glucuronide are the most abundant metabolites, while the parent drug is found at concentration <10 ng mL-1 after 300 min. The knowledge of Phase I and II MT-45 metabolite structure is then crucial to develop analytical methods to identify MT-45 consumption in clinical and forensic testing.

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

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

Fentanyl, fentanyl analogs and novel synthetic opioids: A comprehensive review

Deaths from opioid use are increasing in the US, with a growing proportion due to synthetic opioids. Until 2013, sporadic outbreaks of fentanyl and fentanyl analogs contaminating the heroin supply caused some deaths in heroin users. Since then, fentanyl has caused deaths in every state and fentanyl and its analogs have completely infiltrated the North American heroin supply. In 2014, the first illicit pills containing fentanyl, fentanyl analogs, and other novel synthetic opioids such as U-47700 were detected. These pills, which look like known opioids or benzodiazepines, have introduced synthetic opioids to more unsuspecting customers. As soon as these drugs are regulated by various countries, new compounds quickly appear on the market, making detection difficult and the number of cases likely underreported. Standard targeted analytical techniques such as GC-MS (gas chromatography mass spectrometry) and LC-MS/MS (liquid chromatography tandem mass spectrometry) can detect these drugs, but novel compound identification is aided by nontargeted testing with LC-HRMS (liquid chromatography high resolution mass spectrometry). Fentanyl, fentanyl analogs and other novel synthetic opioids are all full agonists of varying potencies at the μ-opioid receptor, leading to typical clinical effects of miosis and respiratory and central nervous system depression. Due to their high affinity for μ-opioid receptors, larger doses of naloxone are required to reverse the effects than are commonly used. Synthetic opioids are an increasingly major public health threat requiring vigilance from multiple fields including law enforcement, government agencies, clinical chemists, pharmacists, and physicians, to name a few, in order to stem its tide. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'

Case Series of Novel Illicit Opioid-Related Deaths

Novel illicit opioids, such as furanyl fentanyl and U-47700, are being encountered with increasing frequency in street heroin samples and have been confirmed in a series of overdose deaths in Tennessee. In this paper, we report the pathology and toxicology from 11 deaths involving furanyl fentanyl and U-47700. Routine toxicology was performed on postmortem femoral or antemortem hospital blood samples with targeted broad spectrum drug screening using liquid chromatography-time-of-flight mass spectrometry (LC-TOF/MS). Confirmation and quantitation of the opioid agonists U-47700 and furanyl fentanyl was performed by ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) using a novel method. Two cases were identified as containing U-47700 in whole blood (189 and 547 ng/mL), and nine cases contained furanyl fentanyl in whole blood, with concentrations ranging from 2.0 - 42.9 ng/mL. In all 11 cases, the manner of death was deemed accident, with drug intoxication being the primary cause of death; one case was complicated by smoke inhalation. All of the decedents were males ranging from 18-62 years, with the median age being 36 years old. The successful identification and confirmation of these novel illicit opioids in this case series relied on the comprehensive investigation and collaboration of scene investigation, forensic pathology, and forensic toxicology.

Pharmacological characterization of novel synthetic opioids (NSO) found in the recreational drug marketplace

Novel synthetic opioids (NSO) are increasingly encountered in illicit heroin and counterfeit pain pills. Many NSO are resurrected from older biomedical literature or patent applications, so limited information is available about their biological effects. Here we examined the pharmacology of three structurally-distinct NSO found in the recreational drug market: N-(1-(2-phenylethyl)-4-piperidinyl)-N-phenylbutyramide (butyrylfentanyl), 3,4-dichloro-N-[(1R,2R)-2-(dimethylamino)cyclohexyl]-N-methylbenzamide (U-47700) and 1-cyclohexyl-4-(1,2-diphenylethyl)piperazine (MT-45). Radioligand binding and GTPγS functional assays were carried out in cells transfected with murine mu- (MOR-1), delta- (DOR-1) or kappa-opioid receptors (KOR-1). Antinociceptive effects were determined using the radiant heat tail flick technique in mice, and opioid specificity was assessed with the mu-opioid antagonist naloxone. Butyrylfentanyl, U-47700 and MT-45 displayed nM affinities at MOR-1, but were less potent than morphine, and had much weaker effects at DOR-1 and KOR-1. All NSO exhibited agonist actions at MOR-1 in the GTPγS assay. Butyrylfentanyl and U-47700 were 31- and 12-fold more potent than morphine in the tail flick assay, whereas MT-45 was equipotent with morphine. Analgesic effects were reversed by naloxone and absent in genetically-engineered mice lacking MOR-1. Our findings confirm that butyrylfentanyl, U-47700 and MT-45 are selective MOR-1 agonists with in vitro affinities less than morphine. However, analgesic potencies vary more than 30-fold across the compounds, and in vitro binding affinity does not predict in vivo potency. Taken together, our findings highlight the risks to humans who may unknowingly be exposed to these and other NSO when taking adulterated heroin or counterfeit pain medications. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'

Updating the list of known opioids through identification and characterization of the new opioid derivative 3,4-dichloro-N-(2-(diethylamino)cyclohexyl)-N-methylbenzamide (U-49900)

New psychoactive substances have been rapidly growing in popularity in the drug market as non-illegal drugs. In the last few years, an increment has been reported on the use of synthetic alternatives to heroin, the synthetic opioids. Based on the information provided by the European Monitoring Centre for Drug and Drug Addiction, these synthetic opioids have been related to overdoses and deaths in Europe and North America. One of these opioids is the U-47700. A few months ago, U-47700 was scheduled in the U.S. and other countries, and other opioid derivatives have been appearing in order to replace it. One of these compounds is U-49900, an analog of U-47700. A white powder sample was obtained from an anonymous user in Spain. After an accurate characterization by gas chromatography-mass spectrometry, ultra-high performance liquid chromatography-high resolution mass spectrometry, nuclear magnetic resonance and single-crystal X-ray diffraction; and complemented by Fourier-transformed infrared spectroscopy, ultraviolet and circular dichroism spectrophotometry, the drug sample was unequivocally identified as U-49900. The information provided will be useful for the Early Warning System and forensic laboratories for future identifications of the U-49900, as well as in tentative identifications of other related opioids.

Misuse of Novel Synthetic Opioids: A Deadly New Trend

Novel synthetic opioids (NSOs) include various analogs of fentanyl and newly emerging non-fentanyl compounds. Together with illicitly manufactured fentanyl (IMF), these drugs have caused a recent spike in overdose deaths, whereas deaths from prescription opioids have stabilized. NSOs are used as stand-alone products, as adulterants in heroin, or as constituents of counterfeit prescription medications. During 2015 alone, there were 9580 deaths from synthetic opioids other than methadone. Most of these fatalities were associated with IMF rather than diverted pharmaceutical fentanyl. In opioid overdose cases, where the presence of fentanyl analogs was examined, analogs were implicated in 17% of fatalities. Recent data from law enforcement sources show increasing confiscation of acetylfentanyl, butyrylfentanyl, and furanylfentanyl, in addition to non-fentanyl compounds such as U-47700. Since 2013, deaths from NSOs in the United States were 52 for acetylfentanyl, 40 for butyrylfentanyl, 128 for furanylfentanyl, and 46 for U-47700. All of these substances induce a classic opioid toxidrome, which can be reversed with the competitive antagonist naloxone. However, due to the putative high potency of NSOs and their growing prevalence, it is recommended to forgo the 0.4 mg initial dose of naloxone and start with 2 mg. Because NSOs offer enormous profit potential, and there is strong demand for their use, these drugs are being trafficked by organized crime. NSOs present major challenges for medical professionals, law enforcement agencies, and policymakers. Resources must be distributed equitably to enhance harm reduction though public education, medication-assisted therapies, and improved access to naloxone.

An Expanding World of Novel Psychoactive Substances: Opioids

The abuse of novel psychoactive substances (NPS) has been increasing dramatically worldwide since late 2000s. By the end of 2015, more than 560 NPS had been reported to the European Monitoring Centre for Drugs and Drug Addiction. Although the most popular compounds are synthetic cannabinoids and psychostimulatory derivatives of cathinone (so-called β-keto-amphetamines), novel synthetic opioids have recently emerged on the recreational drug market. They include fentanyl (a potent narcotic analgesic) and its analogs (e.g., acetylfentanyl, acryloylfentanyl, carfentanil, α-methylfentanyl, 3-methylfentanyl, furanylfentanyl, 4-fluorobutyrylfentanyl, 4-methoxybutyrylfentanyl, 4-chloroisobutyrylfentanyl, 4-fluoroisobutyrylfentanyl, tetrahydrofuranylfentanyl, cyclopentylfentanyl, and ocfentanil) and compounds with different chemical structures, such as AH-7921, MT-45, and U-47700. This survey provides an overview of the pharmacological properties, pattern of use, and desired and unwanted effects of the above-listed novel opioids. Special emphasis is given to cases of non-fatal and lethal intoxication involving these compounds.

Toxicity evaluation of α-pyrrolidinovalerophenone (α-PVP): results from intoxication cases within the STRIDA project

CONTEXT

An increasing number of new psychoactive substances (NPS) of different chemical classes have become available through marketing and sale over the Internet. This report from the Swedish STRIDA project presents the prevalence, laboratory results, and clinical features in a series of intoxications involving the stimulant NPS α-pyrrolidinovalerophenone (α-PVP), a potent dopamine re-uptake inhibitor, over a 4-year period.

STUDY DESIGN

Observational case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals in Sweden from 2012 to 2015.

PATIENTS AND METHODS

In the STRIDA project, blood and urine samples are collected from intoxicated patients with admitted or suspected intake of NPS or unknown drugs presenting to hospitals over the country. Analysis of NPS is performed by mass spectrometry multicomponent methods. Clinical data are collected when caregivers consult the Swedish Poisons Information Centre (PIC), and retrieved from medical records. The severity of poisoning is graded retrospectively using the Poisoning Severity Score (PSS). The inclusion criteria for this study included absence of other stimulants than α-PVP.

RESULTS

During the 4-year study period, 23 intoxications were originally coded as "α-PVP related" out of a total 3743 NPS-related inquiries (0.6%) at the PIC. The present study covered 42 analytically confirmed cases in which α-PVP was the only stimulant detected. The age range of patients was 20-58 (median 32) years, of which 79% were males. The α-PVP concentration in serum was 4.0-606 (median 64; n = 42) ng/mL and 2.0-41,294 (median 1782; n = 25) ng/mL in urine. There was no statistically significant association between the serum α-PVP concentration and urinary α-PVP/creatinine ratio in 25 cases, where both sets of data were available. In 14/42 (33%) cases, α-PVP was the only psychoactive substance identified. In the remaining cases, additional substances comprised opioids, benzodiazepines, and ethanol. The main clinical manifestations were tachycardia (80%), agitation (70%), hypertension (33%), hallucinations (20%), and delirium (18%). Classification of poisoning severity yielded 25 (60%) moderate (PSS 2), 7 (17%) severe (PSS 3), and 2 fatal cases (PSS 4).

CONCLUSIONS

In analytically confirmed α-PVP intoxication cases involving no other stimulant drugs, the urine and serum concentrations showed high variability. The clinical features were consistent with a severe sympathomimetic toxidrome. The results further demonstrated that α-PVP prevailed as a drug of abuse after being classified as a narcotic substance, and despite a high incidence of severe poisonings and fatalities. However, the low prevalence of α-PVP cases registered at the PIC suggested that many were unaware of the actual substance they had taken.

Acute skin and hair symptoms followed by severe, delayed eye complications in subjects using the synthetic opioid MT-45

BACKGROUND

The introduction of unclassified new psychoactive substances (NPS) on the recreational drugs market through open online sale ('legal highs' or 'Internet drugs') continues unabated and represents a growing health hazard. The use of NPS has resulted in numerous, severe, adverse events and fatalities, due to unintended overdose or unknown toxic side-effects.

OBJECTIVES

To try to find a possible common underlying cause for the skin-hair-eye symptoms complex observed in three men.

METHODS

From late 2013 to mid-2014, three Swedish men aged 23-34 years with a history of recreational drug use independently presented with similar and very remarkable clinical signs, requiring extensive examination and prolonged treatment.

RESULTS

Common clinical signs included hair depigmentation, hair loss, widespread folliculitis and dermatitis, painful intertriginous dermatitis, dry eyes, and elevated liver enzymes. Two of them also showed transverse white Mees' lines (leukonychia striata) on the fingernails and toenails, suggesting a temporary, drug-induced, disorganized keratinization. The clinical signs gradually disappeared over time. However, later on, two developed severe bilateral secondary cataracts requiring surgery. Because drug tests within the Swedish STRIDA project had demonstrated intake of the NPS opioid MT-45 in all patients, this was suspected to be the common causative agent.

CONCLUSIONS

These cases highlight the importance for physicians and health professionals to consider the increasing number of novel, untested recreational drugs, as a potential cause of unusual and otherwise unrecognized clinical signs and symptoms.