Identification of designer drug 2C-E (4-ethyl-2, 5-dimethoxy-phenethylamine) in urine following a drug overdose

Safer Tripping: Serotonergic Psychedelics and Drug Checking. Submission and Detection Rates, Potential Harms, and Challenges for Drug Analysis

Purpose of Review

With the continuous emergence of new psychoactive substances, drug checking (DC) services are challenged by an increasingly complex drug market. Considering the resumed scientific and public interest in serotonergic psychedelics (SPs) like LSD, psilocybin, and 2C-B, we present the results of a literature search investigating the presence and proportion of SPs in DC samples.

Recent Findings

In 15 identified reports, submission and detection rates of SPs were comparably low, but increasing. Samples contained considerable amounts of adulterations or analogues, mostly novel SPs with unknown toxicological profiles and in some cases potentially life-threatening effects. The detection of SPs, however, requires advanced analysis techniques currently not available to most DC services.

Summary

Given the substantial proportion of novel SPs in DC samples and the associated risks, DC can be a valuable harm reduction and monitoring tool for SPs if analysis techniques with high sensitivity are employed.

Acute Effects of 2C-E in Humans: An Observational Study

2,5-Dimethoxy-4-ethylphenethylamine (2C-E) is psychedelic phenylethylamine, with a chemical structure similar to mescaline, used as new psychoactive substance (NPS). It inhibits norepinephrine and serotonin uptake and, more relevant, acts as a partial agonist of the serotonin 2A (5-HT_{2 A}), 2B (5-HT_{2 B}), and (5-HT_{2 C}) receptors. Consumers have reported that 2C-E induces mild-moderate psychedelic effects, but its pharmacology in humans, including pharmacological effects and pharmacokinetics, have not yet studied. To assess the acute effects of 2C-E on physiological and subjective effects and evaluate its pharmacokinetics, an observational study was carried-out. Ten recreational users of psychedelics self-administered a single oral dose of 2C-E (6.5, 8, 10, 15, or 25 mg). Blood pressure and heart rate were evaluated at baseline, 2, 4, and 6 h post-administration. Three rating scales were administered to evaluate subjective effects: a set of Visual Analog Scales (VAS), the 49-item short form version of the Addiction Research Centre Inventory (ARCI), and the Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) at baseline, 2, 4, and 6 h after self-administration. To assess 2C-E concentrations oral fluid (saliva) was collected during 6 h. 2C-E induced primarily alterations in perceptions, hallucinations, and euphoric-mood. Saliva maximal concentrations were achieved 2 h after self-administration. Administration of oral 2C-E at recreational doses produces a group of psychedelic-like effects such to 2C-B and other serotonin-acting drugs.

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.

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.