Mephedrone concentrations in clinical intoxications and fatal cases: a systematic review.

BACKGROUND/PURPOSE: Mephedrone, a ring-substituted synthetic cathinone derivative, gained popularity as a recreational drug in the late 2000s. Reports of fatalities related to mephedrone use have emerged with varying concentrations of blood mephedrone upon forensic investigations. This study aims to evaluate the existing literature on mephedrone concentrations in instances of clinical intoxication and fatal cases. METHODS: We comprehensively searched electronic databases, including Web of Science, PubMed, Embase, and the Cochrane Library, from inception to July 26, 2023. We selected case reports or case series of mephedrone intoxication presented with individual blood mephedrone concentration. Patient demographics, clinical characteristics, blood mephedrone concentrations, and outcomes were extracted for analysis. RESULTS: 77 cases from 14 case reports and 6 case series were identified for review. There were 34 deaths and 43 non-fatal intoxication cases. The median patient's age was 24 years (IQR: 10), and 91.4% were male. Forty-five of the 63 cases (71.4%) were reported with alcohol or other illicit drugs detected. The median blood mephedrone concentration was 0.37 mg/L (IQR: 1.09 mg/L). Death cases were older than non-fatal cases (median = 30 vs. 22 years, p = 0.029). The median blood mephedrone concentration was higher in death cases (1.30 mg/L vs. 0.12 mg/L, p < 0.0001). CONCLUSIONS: Blood mephedrone concentration in dead patients is approximately 11 times higher than in non-fatal cases. This finding could serve as a stepping stone to the diagnosis of concentrations in clinical poisoning cases and deaths, especially in the treatment of poisoning patients. In more extensive prospective studies, further research is necessary to establish a standardized, real-time available methodology and validate the predictive value of mephedrone concentrations in the prognostic value of mephedrone concentrations.

The use of multiple keratinous matrices (head hair, axillary hair, and toenail clippings) can help narrowing a period of drug exposure: experience with a criminal case involving 25I-NBOMe and 4-MMC.

The objective of this publication is to present the interest of collecting several keratinous specimens in order to document possible drug impairment at the time of the assault, when knowledge solely occurred 7 months after. A subject committed a murder and within minutes after the crime self-inflicted serious wounds. He was charged to the hospital where he slowly recovered. After several weeks, he was sent to prison. During this period, intelligence indicated possible drug impairment at the time of the assault after using 25I-NBOMe and 4-MMC. Head hair (4 cm), axillary hair, and toenails were collected 7 months after the crime. New psychoactive substances were tested in each specimen using LC-MS/MS, which revealed the presence of 25I-NBOMe and 4-MMC in axillary hair (2 and 6 pg/mg) and toenails (1 and 5 pg/mg). However, the perpetrator claimed that the positive findings were due to contamination in prison. Therefore, the head hair was also tested and results returned negative (LOQ at 1 pg/mg), demonstrating absence of contamination during the last 4 months before collection. Combining the window of drug detection in axillary hair (about 4 to 8 months) and the one of toenail clippings (up to 8 months), and excluding drug exposure during the previous 4 months as well as external contamination as the head hair results were negative, allowed us to conclude that the positive findings in axillary hair and toenails are more likely than not consistent with consumption of both 25I-NBOMe and 4-MMC at the time of the crime.

Rapid Determination of the 'Legal Highs' 4-MMC and 4-MEC by Spectroelectrochemistry: Simultaneous Cyclic Voltammetry and In Situ Surface-Enhanced Raman Spectroscopy.

The synthetic cathinones mephedrone (4-MMC) and 4-methylethcathinone (4-MEC) are two designer drugs that represent the rise and fall effect of this drug category within the stimulants market and are still available in several countries around the world. As a result, the qualitative and quantitative determination of 'legal highs', and their mixtures, are of great interest. This work explores for the first time the spectroelectrochemical response of these substances by coupling cyclic voltammetry (CV) with Raman spectroscopy in a portable instrument. It was found that the stimulants exhibit a voltammetric response on a gold screen-printed electrode while the surface is simultaneously electro-activated to achieve a periodic surface-enhanced Raman spectroscopy (SERS) substrate with high reproducibility. The proposed method enables a rapid and reliable determination in which both substances can be selectively analyzed through the oxidation waves of the molecules and the characteristic bands of the electrochemical SERS (EC-SERS) spectra. The feasibility and applicability of the method were assessed in simulated seized drug samples and spiked synthetic urine. This time-resolved spectroelectrochemical technique provides a cost-effective and user-friendly tool for onsite screening of synthetic stimulants in matrices with low concentration analytes for forensic applications.

Is the 3,4-methylendioxypyrovalerone/mephedrone combination responsible for enhanced stimulant effects? A rat study with investigation of the effect/concentration relationships.

RATIONALE: The use of synthetic cathinones as recreational drugs frequently sold in combination has been increasing exponentially. However, the consequences of combining cathinones on the resulting stimulant effects and the pharmacokinetics have been poorly investigated. OBJECTIVE AND METHODS: To study 3,4-methylenedioxypyrovalerone (MDPV; 3 mg/kg) and mephedrone (4-MMC; 30 mg/kg)-induced effects on rat locomotor activity and pharmacokinetics, administered alone or in combination by the intragastric route. The pharmacokinetic parameters were determined using non-compartmental analysis and the relationships between the locomotor activity and drug concentrations using sigmoidal Emax modeling. RESULTS: Locomotor activity significantly increased during the first hour post-administration with the MDPV/4-MMC combination in comparison to MDPV (p < 0.001) and 4-MMC (p < 0.01) alone. The pharmacokinetic profile of MDPV, but not 4-MMC, was significantly modified with the combination resulting in decreases in Cmax (16.4 ± 5.5 versus 62.2 ± 14.2 µg/L, p < 0.05) and AUC0 → ∞ (708 ± 91 versus 3316 ± 682 µg/L/min, p < 0.01) and increases in V/F (582.6 ± 136.8 versus 115.9 ± 42.7 L/kg, p < 0.05) and Cl/F (4.6 ± 0.7 versus 1.2 ± 0.4 L/kg/min, p < 0.01) in comparison to MDPV alone. The sigmoidal Emax model fitted the observed data well; MDPV being markedly more potent than 4-MMC (EC50, 0.043 versus 0.7 µmol/L). The enhancing factor representing the MDPV contribution to the alteration in the relationships between locomotor activity and 4-MMC concentrations was 0.3. CONCLUSION: An MDPV/4-MMC combination results in enhanced stimulant effects in the rat, despite significant reduction in MDPV bioavailability. Enhanced effects could be explained by increased MDPV distribution and/or possible complementation at the brain dopaminergic targets. However, the exact consequences of the MDPV/4-MMC combination in humans remain to be clarified.

Evaluation of training dose in male Sprague-Dawley rats trained to discriminate 4-methylmethcathinone.

RATIONALE: Although the synthetic cathinone 4-methylmethcathinone (4-MMC, mephedrone) has been a subject of intensive research investigation, the pharmacological mechanisms involved in its interoceptive stimulus effects have yet to be fully characterized. OBJECTIVE: The present study employed drug discrimination methods in rats to compare the interoceptive stimulus properties of two different training doses of 4-MMC to other substances with similar pharmacological actions. METHODS: Sixteen male Sprague-Dawley rats were trained to discriminate either 1.0 mg/kg (N = 8) or 3.0 mg/kg (N = 8) 4-MMC from saline. Substitution tests were conducted with drugs that increase extracellular monoamine levels (d-amphetamine, (+)-methamphetamine, 4-MMC, MDMA, MDPV, and (-)-cocaine), a serotonin releaser (+)-fenfluramine, and a serotonergic (5-HT2A) hallucinogen (+)-LSD. RESULTS: Stimulus control was established in fewer sessions in the subjects trained with 3.0 mg/kg compared to those trained with 1.0 mg/kg 4-MMC. Cocaine, MDMA, and d-amphetamine produced full substitution in the 1.0 mg/kg 4-MMC-trained rats at doses that did not decrease response rate. However, doses of test drugs that engendered > 80% 4-MMC-lever selection concurrently produced rate-decreasing effects in rats trained to discriminate 3.0 mg/kg 4-MMC. CONCLUSIONS: These findings further characterize the interoceptive stimulus effects of 4-MMC and indicate that these effects vary little with training dose; however, qualitative differences in substitutability of test drugs were observed between training groups. This study expands existing knowledge regarding the psychopharmacology of 4-MMC and the potential neurochemical substrates contributing to its subjective effects.

Mephedrone Concentrations in Cases of Clinical Intoxication.

BACKGROUND: Mephedrone (4-methylmethcathinone, 4-MMC), a ring-substituted synthetic cathinone derivative has become established as a permanent illicit drug in the dynamic new psychoactive substances (NPS) scene. OBJECTIVE: This review summarizes current knowledge on mephedrone concentrations in biological samples from cases of acute intoxications (fatal and non-fatal), pharmacokinetics studies, wastewater and anonymous pooled urine analysis in order to provide an overview of the reliable scientific knowledge on toxicokinetics of mephedrone in humans. METHOD: The PubMed® database complemented with Google Scholar® was systematically searched to find published cases of mephedrone intoxications. The searches were done using the keyword "mephedrone OR 4- methylmethcathinone" in association to each of the following strategies: i) "intoxication OR poisoning"; ii) "(blood OR serum OR plasma") OR "urine" OR ("saliva OR oral fluid") OR "hair"; iii) "forensic toxicology samples"; iv) "wastewater OR sewage OR pooled urine" and v) "toxicity OR death OR fatal". RESULTS: Since 2010, a total of 97 fatal cases and 57 non-fatal intoxication cases were identified that presented mephedrone concentrations in human biological matrices attributed directly or indirectly to mephedrone. Typical subjects involved were young male with concomitant use of other drugs (psychostimulants, cannabis, alcohol and other depressants). Mephedrone mean blood concentration from fatal cases was 2,663 ng/mL (range 51-22,000 ng/mL), from non-fatal cases was 166 ng/mL (range, 13-412 ng/mL), that resulted in a similar range from data found in controlled studies with no acute toxicity associated (135 ng/mL, range 52-218 ng/mL). Forensic epidemiology studies based on wastewater and anonymous pooled urine analysis point towards similar variations in use (nightclub scene) to those self-reported in surveys and questioners. CONCLUSION: Mephedrone blood concentrations in cases of fatal intoxications were higher than in non-fatal cases. In both cases, great variability in mephedrone concentration potentially attributable to interindividual differences in pharmacokinetics-pharmacodynamics and poly-drug use complicates the interpretation of the forensic toxicological analysis.

Clinical Pharmacology of the Synthetic Cathinone Mephedrone.

4-Methyl-N-methylcathinone (mephedrone) is a popular new psychoactive substance (NPS) that is structurally related to the parent compound cathinone, the ß-keto analogue of amphetamine. Mephedrone appeared on the street drug market as a substitute for 3,4-methylenedioxy-N-methylamphetamine (MDMA, ecstasy) and was subsequently banned due to the potential health risks associated with its use. Nevertheless, mephedrone continues to be widely consumed among specific populations, with unique patterns of misuse. To date, most information about the biological effects of mephedrone comes from user experiences, epidemiological data, clinical cases, toxicological findings, and animal studies, whilst there are very few data regarding its human pharmacodynamics and pharmacokinetics. This chapter reviews the available published data on patterns of mephedrone use, its acute and chronic effects, and its pharmacokinetic properties. More human research is needed to elucidate the safety, toxicity, and addiction potential of mephedrone and related NPS.

Sensitization to the locomotor stimulant effects of "bath salt" constituents, 4-methylmethcathinone (4-MMC) and 3,4-methylenedioxypyrovalerone (MDPV), in male Sprague-Dawley rats.

BACKGROUND: Synthetic cathinones, 4-methylmethcathinone (4-MMC) and 3,4-methylenedioxypyrovalerone (MDPV), serve as a substrate or blocker at monoaminergic transporters, respectively, and produce locomotor stimulant effects in rodents. The present study investigated in rats the effects of repeated exposure to 4-MMC, MDPV, or mixtures of the two on the induction of locomotor sensitization and expression of cross-sensitization to cocaine. METHODS: Seventy-two male Sprague-Dawley rats received daily intraperitoneal injections of saline, MDPV (0.5mg/kg), 4-MMC (0.5, 1.0, or 2.0mg/kg) or mixtures of 0.5mg/kg MDPV+4-MMC (0.5, 1.0, or 2.0mg/kg) for seven consecutive days. Locomotor activity was recorded on days 1 and 7 and again after an acute injection of 5mg/kg cocaine following a 10day drug washout period. RESULTS: Rats injected with 0.5mg/kg MDPV, 0.5, 1.0, or 2.0mg/kg 4-MMC, or 2.0mg/kg 4-MMC+0.5mg/kg MDPV displayed time-dependent increases in horizontal activity that were augmented on day 7 compared to day 1. In addition, rats pretreated with 0.5mg/kg MDPV, 2.0mg/kg 4-MMC, or mixtures of 4-MMC+MDPV displayed an enhanced response to cocaine. CONCLUSIONS: Locomotor responses sensitize to MDPV and to certain mixtures of MDPV and 4-MMC following repeated dosing. Furthermore, previous exposure to these substances may produce cross-sensitization to the locomotor stimulant effects of cocaine. Considered together with recent findings that 4-MMC and MDPV have different sites of action, but both influence monoaminergic functioning, further investigations utilizing a variety of behavioral assays may prove informative regarding the abuse liability of synthetic cathinone mixtures.