Antipsychotic-Related DRESS Syndrome: Analysis of Individual Case Safety Reports of the WHO Pharmacovigilance Database

Introduction Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is gaining attention in pharmacovigilance, but its association with antipsychotics, other than clozapine, is still unclear. Methods We conducted a case/non-case study with disproportionality analysis based on the World Health Organization (WHO) global spontaneous reporting database, VigiBase®. We analyzed individual case safety reports of DRESS syndrome related to antipsychotics compared to (1) all other medications in VigiBase®, (2) carbamazepine (a known positive control), and (3) within classes (typical/atypical) of antipsychotics. We calculated reporting odds ratio (ROR) and Bayesian information component (IC), with 95% confidence intervals (CIs). Disproportionate reporting was prioritized based on clinical importance, according to predefined criteria. Additionally, we compared characteristics of patients reporting with serious/non-serious reactions. Results A total of 1534 reports describing DRESS syndrome for 19 antipsychotics were identified. The ROR for antipsychotics as a class as compared to all other medications was 1.0 (95% CI 0.9–1.1). We found disproportionate reporting for clozapine (ROR 2.3, 95% CI 2.1–2.5; IC 1.2, 95% CI 1.1–1.3), cyamemazine (ROR 2.3, 95% CI 1.5–3.5; IC 1.2, 95% CI 0.5–1.7), and chlorpromazine (ROR 1.5, 95% CI 1.1–2.1; IC 0.6, 95% CI 0.1–1.0). We found 35.7% of cases with co-reported anticonvulsants, and 25% with multiple concurrent antipsychotics in serious compared to 8.6% in non-serious cases ( p = 0.03). Fatal cases were 164 (10.7%). Conclusions Apart from the expected association with clozapine, chlorpromazine and cyamemazine (sharing an aromatic heteropolycyclic molecular structure) emerged with a higher-than-expected reporting of DRESS. Better knowledge of the antipsychotic-related DRESS syndrome should increase clinicians’ awareness leading to safer prescribing of antipsychotics. Supplementary Information The online version contains supplementary material available at 10.1007/s40264-024-01431-7.