Emergency Department presentations due to new psychoactive substances (NPS) and other illicit drugs: a clinical and toxicological study on recreational drug toxicity in Italy.

Although the use of new psychoactive substances (NPS) has increased worldwide, current drug monitoring systems in emergency departments (EDs) across several European countries including Italy, remain mainly focused on classical drugs of abuse. This study aimed to assess the prevalence of NPS, ketamine and other illicit drugs in patients presenting to ED in Bologna, Italy, collecting associated clinical and toxicological data. METHODS: This observational study included patients presenting to the ED of the University-Hospital of Bologna (IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy), between March and November 2024, with suspected acute recreational drug toxicity. Patient demographics and clinical features were recorded, and blood samples were analyzed for NPS and other drugs, using a previously validated and updated liquid chromatography-tandem mass spectrometry (LC–MS/MS) method. RESULTS: Of the 110 patients enrolled, 67 (60.9%) tested positive for at least one drug. Cocaine was the most frequently detected substance (n = 50; 74.6% of positive cases). Twenty patients tested positive for ketamine or norketamine (25.4% of positive cases), with mean values of 55 ng/ml and 101 ng/ml, respectively. NPS were detected in 3 patients (4.5% of positive cases) and consisted of methylone in 2 cases (below the limit of quantification), alpha-PHP (below the limit of quantification) and 3,4-MD-alpha-PHP in one case (16 ng/ml). DISCUSSION: Our study reveals a high prevalence of ketamine use, and a predominance of stimulants, particularly synthetic cathinones, among NPS. The association of NPS with psychomotor agitation underscores the clinical importance of considering these substances in cases of severe agitation. These findings emphasize the evolving landscape of recreational drug use and the critical role of comprehensive toxicological screening in emergency settings.