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<h3>Background and Importance</h3> Metamizole (dipyrone) is a non-opioid analgesic widely used for pain and fever. Although effective, its association with blood dyscrasias–particularly agranulocytosis–led to withdrawal in several countries. In Southern Europe, however, its safety remains widely accepted. Evidence suggests possible ethnic or genetic susceptibility, especially among Northern Europeans, but real-world data are scarce. Clarifying this risk is essential to improve pharmacovigilance, ensure patient safety, and guide appropriate analgesic use in diverse populations. <h3>Aim and Objectives</h3> This study aimed to estimate the incidence and relative risk of metamizole-induced agranulocytosis or neutropenia, comparing adults of Northern versus Southern European origin, and to identify possible ethnic differences in adverse reactions using hospital and outpatient real-world data. <h3>Material and Methods</h3> A retrospective observational study was conducted in five regional health departments with a high Northern European resident population. Data from 2016–2017 were obtained using the <i>Alumbra</i> platform, identifying hospital admissions in the CMBD database with ICD-10 codes for drug-induced neutropenia or agranulocytosis (D70.2, D70.8, D70.9, and related T39 codes). Patients >45 years exposed to metamizole within one month before admission were included. Cases with neoplastic, haematologic, or infectious causes were excluded. Each case was reviewed individually. Incidence was expressed per 100,000 DDD and per 1,000 treated patients. <h3>Results</h3> A total of 555 hospitalisations were identified; 41 met inclusion criteria. Of these, 26 were of Northern European origin and 11 of Southern European origin. The incidence of agranulocytosis was 39.8 vs. 0.33 cases per 100,000 DDD (RR = 120.6). Nine deaths occurred, seven among Northern European patients. <h3>Conclusion and Relevance</h3> Real-world data revealed a significantly higher relative risk of agranulocytosis associated with metamizole in Northern European origin patients. Although the absolute incidence remains low, the findings support targeted pharmacovigilance, genetic susceptibility research, and cautious prescribing in susceptible populations. <h3>References and/or Acknowledgements</h3> 1. Ibáñez L, Vidal X, Ballarín E, Laporte JR. Agranulocytosis associated with metamizole. <i>Eur J Clin Pharmacol.</i> 2005;<b>60</b>:821–9. 2. Stammschulte T, Ludwig WD, Mühlbauer B, <i>et al.</i> Metamizole-associated agranulocytosis: analysis of spontaneous reports 1990-2012. <i>Eur J Clin Pharmacol.</i> 2015;<b>71</b>:1129–38. 3. Vlahov V, Bacracheva N, Tontcheva D, <i>et al</i>. Genetic factors and risk of agranulocytosis from metamizole. <i>Pharmacogenetics.</i> 1996;<b>6</b>:67–72. 4. Shah RR. Metamizole-induced agranulocytosis: does risk vary by ethnicity? <i>J Clin Pharm Ther.</i> 2018;<b>43</b>:556–64. <h3>Conflict of Interest</h3> No conflict of interest