BACKGROUND: Ketamine analogues are emerging dissociative substances structurally related to ketamine and increasingly detected on drug markets worldwide. This study aimed to characterize patterns of use, user profiles, and associated health outcomes in France.

METHODS: We conducted a retrospective analysis of cases involving ketamine analogues reported to the French Addictovigilance Network up to 31 December 2024. Substances of interest included 2-fluorodeschloroketamine (2-FDCK), deschloroketamine (DCK), N-ethyldeschloroketamine (O-PCE), fluorexetamine (FXE), and hydroxetamine (HXE). Cases were reported by healthcare professionals and reviewed by clinical pharmacologists. Data were extracted from the French National Pharmacovigilance Database and the DRAMES (drug-related deaths) registry.

RESULTS: Fifty-six cases were identified from 2017 to 2024, predominantly involving 2-FDCK (52 %) and O-PCE (38 %). Most users were men (93 %), with a mean age of 32.1 years (range: 17-57). Adverse effects were mainly neurological and psychiatric, including dissociation and impaired consciousness. Serious cases accounted for 61 %, including 11 % deaths recorded in the DRAMES registry. Four user profiles were identified through qualitative analysis of case narratives: recreational experimenters, self-medicating individuals, regular users, and individuals unintentionally exposed to adulterated or substituted substances (e.g., sold as synthetic cathinones, cocaine or ketamine). Unintentional exposure, particularly in chemsex contexts, was frequently associated with distressing experiences.

CONCLUSIONS: Ketamine analogue use is increasing in France, consistent with international trends. These substances pose significant health risks, potentially differing from or exceeding those of ketamine. Strengthened surveillance, improved analytical detection, and targeted harm reduction strategies are needed to mitigate their public health impact.