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.