Misuse of obesity drugs exposes patients to serious and preventable harms: A French nationwide pharmacovigilance case series

INTRODUCTION: The rapid uptake of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) for obesity has been accompanied by increasing use outside approved indications and medical supervision. Evidence regarding the harms associated with such misuse remains limited because these situations are not captured in clinical trials and are difficult to identify in healthcare databases. METHODS: A nationwide pharmacovigilance study was performed on adverse drug reactions (ADRs) involving a GLP-1 receptor agonist or GLP-1/GIP co-agonist used in a misuse context and reported to the French pharmacovigilance system between January 2021 and January 2026. Misuse included inappropriate use outside approved indications, dosing recommendations, contraindications or medical supervision requirements. RESULTS: Seventy-two cases were identified, 58% of which were serious. Patients were predominantly female (83%) and young (median age 30 years), with five cases involving minors. Gastrointestinal disorders accounted for 77.7% of reports. Serious ADRs included acute pancreatitis (n = 9), paralytic ileus, gastroparesis, ketoacidosis and severe hypoglycaemia. Among cases with available dosing information, overdosing was involved in 76.4%. In nearly two-thirds of cases, drugs were obtained outside any medical framework through relatives, social media, online sources or the black market. More than half of all cases were reported during the final year of the study period. DISCUSSION: Misuse of GLP-1 RAs is increasing and is associated with serious but largely preventable harm. Unsupervised access, excessive dosing and use of unregulated products appear to be the principal drivers of risk. These findings support stronger measures to limit inappropriate access and improve risk communication regarding GLP-1 therapies.