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

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.

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.

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).

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.