Acute toxic effects related to 4-fluoroamphetamine

Chemical composition of Ecstasy tablets seized in Poland between 2005 and 2020

PURPOSE

The most commonly associated substance found in Ecstasy tablets is MDMA (3,4-methylenedioxymethamphetamine). In our study, we showed how the composition of psychoactive ingredients in Ecstasy tablets seized on the drug market in Poland has changed in the years 2005-2020.

METHODS

The study material consisted of nearly 20,000 single Ecstasy tablets seized by representatives of law enforcement (the police, prosecutors) from 2005 to 2020 and analysed by the Institute of Forensic Research, Krakow, Poland. The analysis of the tablets was carried out by gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography with diode array detection (HPLC-DAD) and ultra-high-performance liquid chromatography with photodiode array detection (UHPLC-PDA).

RESULTS

Currently, new types of MDMA tablets are introduced onto the market, available in various colours and shapes. Our study showed that tablets sold on the street as Ecstasy have variable purity and sometimes contain little or no MDMA. The mean content of MDMA in one tablet seized in 2005-2011 decreased from 90 to 50 mg. In 2013, Ecstasy tablets with a very high MDMA content (average 195 mg per tablet) appeared on the market, but in the next 2 years, the MDMA content decreased again. From 2016, the average MDMA content began to rise again, ranging from 60 to 280 mg.

CONCLUSION

Tablets sold as Ecstasy also contained completely different psychoactive substances, including new psychoactive substances (NPS) (found in almost 20% of all examined tablets sold as Ecstasy) belonging to different chemical groups or their dangerous combinations (i.e. phenylethylamines, piperazines, tryptamines, cathinones, arylalkylamines, arylcyclohexylamines and piperidines). Such a large variety of psychoactive substances in Ecstasy tablets is associated with a high risk for users unaware of their composition.

Fatal Intoxications from a Combination of 4-Fluoroamphetamine and 25C-NBOMe

Six fatalities have occurred from the ingestion of a combination of new psychoactive substances (NPSs), 4-fluoroamphetamine (4FA) and 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25C-NBOMe) over a 9-month period. Four of these fatalities (one older female and three young males) were from direct adverse effects of drugs, and one each from a fall while being intoxicated and during restraint. All cases were subject to full postmortem examinations that included collection of femoral blood. The four drug-caused fatalities had postmortem blood concentrations for 4FA and 25C-NBOMe of 330-682 ng/L (median 417) and 1.4-12 ng/mL (median 4.3), respectively. The other two cases (both young males) where death was considered to have been caused indirectly by drug intoxication had 4FA and 25C-NBOMe postmortem concentrations of 21 and 123 ng/mL, and 1.8 and 4.5 ng/mL, respectively. None of these cases showed concentrations of drugs that suggested use of high recreational doses. In one drug-caused death, capsules and a brown powder obtained from the scene were found to contain a mixture of these two NPSs. With the exception of one drug-caused death, other drugs were detected; however, the effects of the two NPSs together were regarded as the primary triggers for the deaths. There were no consistent symptoms or pathology in these cases; however, agitation/aggression was observed in two cases prior to their collapse, with seizures in possibly three cases. Pulmonary and/or cerebral edema was noted in three cases. Potentially significant natural disease (a mildly enlarged heart) was only observed in one drug-caused case. These cases illustrate a possible increased risk of sudden death with this combination of drugs, both of which can elevate serotonin concentrations as well as act as strong stimulants. These cases also illustrate the difficulty in detecting NPS in cases where no prior information is available that might suggest their use.

Urine toxicology screening by liquid chromatography time-of-flight mass spectrometry in a quaternary hospital setting

OBJECTIVE

Validation of a non-targeted method for urine drug screening (UDS) by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF), and comparison to an established GC-MS method in a hospital setting.

METHODS

217 UDS specimens sent to a quaternary hospital pathology department, were analysed by a CEDIA® immunoassay screen (six drug panels; amphetamines, barbiturates, benzodiazepines, cocaine metabolites, cannabinoids and opiates) on an Abbott Architect instrument. Specimens were subsequently analysed by an established non-targeted qualitative GC-MS method and results compared with a general unknown screening method by LC-QTOF that was under evaluation as a replacement method.

RESULTS

42 selected drugs were evaluated; limits of identification ranged from 2 to 100 µg/L and most drugs (n = 39) were stabile for 24 h after preparation. Matrix effects greater than 25% were observed in seven of the selected drugs. 87% of the specimens tested positive to 1 or more drug panels in a CEDIA® screen. A total of 537 positive drug findings were identified by GC-MS compared to 1,267 positive findings by LC-QTOF. On average, each GC-MS screen identified 2.5 ± 1.8 drugs and the LC-QTOF screen identified 5.8 ± 3.2 drugs. No drugs were identified in 11.3% of the GC-MS screens, whereas drugs were detected in 99% of these by the LC-QTOF. In almost all instances, the LC-QTOF screen could provide mass spectrometric confirmatory results of positive immunoassay screens and was able to identify a wider range of additional drugs and drug metabolites.

CONCLUSIONS

The described general unknown screening (non-targeted, qualitative) LC-QTOF method can detect a larger range of drugs encountered in a hospital setting. The method has been shown to be suitable for comprehensive toxicology screening in a clinical toxicology laboratory.

International snapshot of new psychoactive substance use: Case study of eight countries over the 2019/2020 new year period

There is considerable concern around the use of new psychoactive substances (NPS), but still little is known about how much they are really consumed. Analysis by forensics laboratories of seized drugs and post-mortem samples as well as hospital emergency rooms are the first line of identifying both 'new' NPS and those that are most dangerous to the community. However, NPS are not necessarily all seized by law enforcement agencies and only substances that contribute to fatalities or serious afflictions are recorded in post-mortem and emergency room samples. To gain a better insight into which NPS are most prevalent within a community, complementary data sources are required. In this work, influent wastewater was analysed from 14 sites in eight countries for a variety of NPS. All samples were collected over the 2019/2020 New Year period, a time which is characterized by celebrations and parties and therefore a time when more NPS may be consumed. Samples were extracted in the country of origin following a validated protocol and shipped to Australia for final analysis using two different mass spectrometric strategies. In total, more than 200 were monitored of which 16 substances were found, with geographical differences seen. This case study is the most comprehensive wastewater analysis study ever carried out for the identification of NPS and provides a starting point for future, ongoing monitoring of these substances.

Chiral Serum Pharmacokinetics of 4-Fluoroamphetamine after Controlled Oral Administration: Can (R)/(S) Concentration Ratios Help in Interpreting Forensic Cases?

Over the last two decades, misuse of 4-fluoroamphetamine (4-FA) became an emerging issue in many European countries. Stimulating effects last for 4-6 hours and can impact psychomotor performance. The metabolism of amphetamine-type stimulants is stereoselective and quantification of (R)- and (S)-enantiomers has been suggested for assessing time of use. To date no data on enantioselective pharmacokinetics is available for 4-FA in serum samples. An enantioselective liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed using a chiral Phenomenex® Lux 3 μm AMP column. Validation of the method showed satisfactory selectivity, sensitivity, linearity (0.5-250 ng/mL), precision and accuracy. Recreational stimulant users orally ingested two doses (100 mg, n=12, and 150 mg, n=5) of 4-FA. Blood samples were drawn prior to application and over a period of 12 hours after ingestion and analyzed for 4-FA enantiomers. Peak concentrations and corresponding times did not differ significantly between the enantiomers (mean (R)/(S)-ratio at tmax 1.05, 0.85-1.16). With mean 12.9 (8.3-16.1) hours, apparent elimination half-lives (t1/2) were significantly (p < 0.01) longer for (R)-4-FA than for (S)-4-FA (6.0 hours; range 4.4-10.2 hours) and independent of the dose given. Over time, (R)/(S)-concentration-ratios were linearly increasing in all subjects to maximum ratios of 2.00 (1.08-2.77) in the last samples (after 12 hours). The slopes of the (R)/(S)-ratio exhibited marked inter-individual differences (0.023 to 0.157 h-1, mean 0.095 h-1). Ratios higher than 1.60 only appeared earliest after a minimum of 6 hours and therefore suggest the absence of acute drug effects. Different elimination half-lives of enantiomers lead to constantly increasing (R)/(S)-concentration-ratios. Consequently, ratios of 4-FA enantiomers in serum are a promising indicator for assessment of the time of drug consumption.

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.

Para-Halogenation Affects Monoamine Transporter Inhibition Properties and Hepatocellular Toxicity of Amphetamines and Methcathinones

Halogenated derivatives of amphetamine-type stimulants are appearing on the drug market, often with altered pharmacological profile and sometimes different legal status compared to the non-halogenated substances. The aim of the present study was to investigate the pharmacological profile and hepatocellular toxicity of para-halogenated amphetamines and cathinones. The potential of amphetamine, 4-fluoroamphetamine, 4-chloroamphetamine, methcathinone, 4-fluoromethcathinone, and 4-chloromethcathinone to inhibit the monoamine transporters for norepinephrine, dopamine, and serotonin was determined in transporter-transfected human embryonic kidney 293 cells. Cell membrane integrity, ATP content, oxygen consumption rate, and superoxide levels were measured in human hepatoma HepG2 cells after exposure to the substances for 24 h. All compounds inhibited the norepinephrine transporter at submicromolar concentrations and the dopamine transporter at low micromolar concentrations. The selectivity of the compounds to inhibit the dopamine versus serotonin transporter decreased with increasing size of the para-substituent, resulting in potent serotonin uptake inhibition for the halogenated derivatives. All substances depleted the cellular ATP content at lower concentrations (0.25–2 mM) than cell membrane integrity loss occurred (≥0.5 mM), suggesting mitochondrial toxicity. The amphetamines and 4-chloromethcathinone additionally impaired the mitochondrial respiratory chain, confirming mitochondrial toxicity. The following toxicity rank order for the para-substituents was observed: chloride > fluoride > hydrogen. In conclusion, para-halogenation of stimulants increases the risk for serotonergic neurotoxicity. Furthermore, para-halogenation may increase hepatic toxicity mediated by mitochondrial impairment in susceptible users.

Drug liking and wanting, not impulsive action or reflection is increased by 4-fluoroamphetamine

BACKGROUND

New psychoactive substances (NPS) are chemical analogues designed to mimic the effects of various classic recreational drugs of abuse including MDMA, LSD, and cannabis. NPS use is associated with concern about the acute and longer-term effects particular substances might have, with abuse and addiction as potential consequences. Impulsivity and sensitivity to the rewarding effects of drugs have been considered as risk factors for drug abuse. In light of the popularity of 4-fluoroamphetamine (4-FA), it is important to assess whether 4-FA can lead to subjective drug liking and wanting, and impulsive behavior, all factors contributing to the abuse likelihood of a substance.

METHODS

A placebo-controlled 2-way crossover study in 12 healthy poly-drug using participants was conducted to test subjective and behavioral effects of 4-FA (100 mg). 4-FA concentrations were determined in serum up to 12 h after administration and two impulsivity tasks and two drug experience questionnaires assessing drug liking and wanting, and good and bad drug effect, were administered between 1 and 11 h post-administration.

RESULTS

Findings showed that 4-FA did not affect impulsive behavior. Self-ratings of drug liking and wanting and good drug effect were increased 1 h after administration; this effect was absent 11 h after drug intake.

DISCUSSION AND CONCLUSION

To conclude, 4-FA (single dose) increased self-rated liking and wanting, which is known to contribute to the abuse likelihood of a substance; however, it left another factor impulsive behavior unaffected. It has to be noted that the current picture is limited and might change with increased sample size, and/or different 4-FA doses.

CLINICAL TRIAL REGISTRATION

Trial acronym: 4-FA. URL: http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=6164 . Registration number: NTR6164 (Dutch clinical trial registry number).

Safety Profile and Neurocognitive Function Following Acute 4-Fluoroamphetamine (4-FA) Administration in Humans

Availability of novel psychoactive substances (NPS) exponentially increased over the last years. Risk evaluations of NPS are hampered by the lack of pharmacological studies in humans on health parameters. The aim of the present study was to evaluate safety and neurocognitive function of healthy volunteers (N = 12) who received single doses of 100 and 150 mg 4-fluoroamphetamine (4-FA), a phenethylamine that has been associated with severe cardiovascular and cerebrovascular complications. The study was set-up as a placebo controlled, within subject, phase 1 trial as it was the first to administer 4-FA to humans under controlled conditions. Overall, 4-FA produced a strong elevation in blood pressure up until 4–5 h after administration that was followed by a sustained increase in heart rate. After an interim review of safety data from five participants, a decision was taken to cancel administration of 150 mg. We subsequently obtained complete datasets for placebo and 100 mg 4-FA treatments only. Effects of 4-FA on mood and neurocognitive function were most distinct at 1 h post drug and included significant elevations of vigor, friendliness, elation, arousal, positive mood, as well as improvements in attention and motor performance. Negative affect was also reported as time progressed in the acute phase and even more so during the subacute phase. Overall, the influence of 4-FA on vital signs, mood, and neurocognition was similar to that observed with other stimulants. Present findings confirm clinical observations of acute toxicity among 4-FA users and warrant warnings about potential health risks associated with 4-FA use.

Pharmacology of MDMA- and Amphetamine-Like New Psychoactive Substances

New psychoactive substances (NPS) with amphetamine-, aminoindan-, and benzofuran basic chemical structures have recently emerged for recreational drug use. Detailed information about their psychotropic effects and health risks is often limited. At the same time, it emerged that the pharmacological profiles of these NPS resemble those of amphetamine or 3,4-methylenedioxymethamphetamine (MDMA). Amphetamine-like NPS induce psychostimulation and euphoria mediated predominantly by norepinephrine (NE) and dopamine (DA) transporter (NET and DAT) inhibition and transporter-mediated release of NE and DA, thus showing a more catecholamine-selective profile. MDMA-like NPS frequently induce well-being, empathy, and prosocial effects and have only moderate psychostimulant properties. These MDMA-like substances primarily act by inhibiting the serotonin (5-HT) transporter (SERT) and NET, also inducing 5-HT and NE release. Monoamine receptor interactions vary considerably among amphetamine- and MDMA-like NPS. Clinically, amphetamine- and MDMA-like NPS can induce sympathomimetic toxicity. The aim of this chapter is to review the state of knowledge regarding these substances with a focus on the description of the in vitro pharmacology of selected amphetamine- and MDMA-like NPS. In addition, it is aimed to provide links between pharmacological profiles and in vivo effects and toxicity, which leads to the conclusion that abuse liability for amphetamine-like NPS may be higher than for MDMA-like NPS, but that the risk for developing the life-threatening serotonin syndrome may be increased for MDMA-like NPS.

Effect fingerprinting of new psychoactive substances (NPS): What can we learn from in vitro data?

The use of new psychoactive substances (NPS) is increasing and currently >600 NPS have been reported. However, limited information on neuropharmacological and toxicological effects of NPS is available, hampering risk characterization. We reviewed the literature on the in vitro neuronal modes of action to obtain effect fingerprints of different classes of illicit drugs and NPS. The most frequently reported NPS were selected for review: cathinones (MDPV, α-PVP, mephedrone, 4-MEC, pentedrone, methylone), cannabinoids (JWH-018), (hallucinogenic) phenethylamines (4-fluoroamphetamine, benzofurans (5-APB, 6-APB), 2C-B, NBOMes (25B-NBOMe, 25C-NBOMe, 25I-NBOMe)), arylcyclohexylamines (methoxetamine) and piperazine derivatives (mCPP, TFMPP, BZP). Our effect fingerprints highlight the main modes of action for the different NPS studied, including inhibition and/or reversal of monoamine reuptake transporters (cathinones and non-hallucinogenic phenethylamines), activation of 5-HT₂receptors (hallucinogenic phenethylamines and piperazines), activation of cannabinoid receptors (cannabinoids) and inhibition of NDMA receptors (arylcyclohexylamines). Importantly, we identified additional targets by relating reported effect concentrations to the estimated human brain concentrations during recreational use. These additional targets include dopamine receptors, α- and β-adrenergic receptors, GABA_Areceptors and acetylcholine receptors, which may all contribute to the observed clinical symptoms following exposure. Additional data is needed as the number of NPS continues to increase. Also, the effect fingerprints we have obtained are still incomplete and suffer from a large variation in the reported effects and effect sizes. Dedicated in vitro screening batteries will aid in complementing specific effect fingerprints of NPS. These fingerprints can be implemented in the risk assessments of NPS that are necessary for eventual control measures to reduce Public Health risks.

Measuring inhibition of monoamine reuptake transporters by new psychoactive substances (NPS) in real-time using a high-throughput, fluorescence-based assay

The prevalence and use of new psychoactive substances (NPS) is increasing and currently over 600 NPS exist. Many illicit drugs and NPS increase brain monoamine levels by inhibition and/or reversal of monoamine reuptake transporters (DAT, NET and SERT). This is often investigated using labor-intensive, radiometric endpoint measurements. We investigated the applicability of a novel and innovative assay that is based on a fluorescent monoamine mimicking substrate. DAT, NET or SERT-expressing human embryonic kidney (HEK293) cells were exposed to common drugs (cocaine, dl-amphetamine or MDMA), NPS (4-fluoroamphetamine, PMMA, α-PVP, 5-APB, 2C-B, 25B-NBOMe, 25I-NBOMe or methoxetamine) or the antidepressant fluoxetine. We demonstrate that this fluorescent microplate reader-based assay detects inhibition of different transporters by various drugs and discriminates between drugs. Most IC₅₀ values were in line with previous results from radiometric assays and within estimated human brain concentrations. However, phenethylamines showed higher IC₅₀ values on hSERT, possibly due to experimental differences. Compared to radiometric assays, this high-throughput fluorescent assay is uncomplicated, can measure at physiological conditions, requires no specific facilities and allows for kinetic measurements, enabling detection of transient effects. This assay is therefore a good alternative for radiometric assays to investigate effects of illicit drugs and NPS on monoamine reuptake transporters.