Adverse event reporting for radiopharmaceuticals in Brazil: a vigimed pharmacovigilance study with disproportionality and international safety intercomparison

Radiopharmaceuticals are expanding rapidly as diagnostic, therapeutic and theranostic agents, but national post-marketing safety evidence remains limited in many health systems. Brazil has used VigiMed, the national implementation of VigiFlow, since December 2018 and has made part of its pharmacovigilance database publicly available. This study assessed adverse event reports involving radiopharmaceuticals in VigiMed, with emphasis on national reporting patterns and radiopharmacy-relevant safety issues. We conducted a retrospective cross-sectional analysis of spontaneous adverse event reports available in VigiMed from 10 December 2018 to 26 May 2026. Radiopharmaceuticals were identified through ATC codes V09/V10, explicit radionuclide or vector terminology, and commercial product names, followed by manual exclusion of false positives. Reports were described at the report, medicinal-product and MedDRA event levels. Radium-223 dichloride ([²²³Ra]RaCl₂; Xofigo) and lutetium (¹⁷⁷Lu) vipivotide tetraxetan ([¹⁷⁷Lu]Lu-PSMA-617; Pluvicto) were compared descriptively because of the small number of reports, lack of exposure denominators and sparse event categories. Exploratory disproportionality was assessed using proportional reporting ratio (PRR), reporting odds ratio (ROR) and Yates-corrected chi-square statistics. International evidence was used only for contextual interpretation. Among 333,622 unique medication-linked reports, 191 radiopharmaceutical drug entries were identified in 126 unique reports, comprising 483 MedDRA-coded events. Xofigo and Pluvicto accounted for 132 of 191 entries (69.1%). Demographic coverage was available for 54 reports (42.9%), among which male sex (77.8%), São Paulo as reporting state (70.4%), and industry E2B submission (64.8%) predominated. Overall, 188 events (38.9%) were serious and 29 (6.0%) had a fatal outcome code. Xofigo and Pluvicto showed qualitatively distinct reporting patterns: Xofigo reports were dominated by neoplasm and musculoskeletal terms, largely reflecting metastatic castration-resistant prostate cancer and bone involvement, whereas Pluvicto reports included more general disorders, investigations, hematologic terms, dysgeusia and systemic symptoms. Twenty-five Preferred Terms met Evans PRR criteria; after separating indication-confounded terms, interpretable signals included myelosuppression, blood alkaline phosphatase increased, bone pain, extravasation, administration-site extravasation, hemoglobin decreased, platelet count decreased, thrombocytopenia, anemia, dysgeusia, fatigue and pain in extremity. Fatal reports were concentrated in advanced prostate cancer and were not interpreted as evidence of treatment-related mortality. Brazilian VigiMed reports capture radiopharmaceutical safety and reporting patterns that are broadly coherent with established international evidence. The principal contribution of this Latin American dataset is the characterization of the national reporting profile and of actionable radiopharmacy-related issues, particularly hematologic monitoring, salivary/taste symptoms with PSMA-targeted therapy, and radiopharmaceutical extravasation. The findings are signal-generating and should not be interpreted as incidence, comparative-risk or causal estimates.