Class-level drug safety surveillance in hospital practice: A pharmacovigilance analysis of 84 therapeutic subclasses from a South Asian tertiary care center.

Objective: Post-marketing drug surveillance is critical for strengthening pharmacovigilance in low- and middle-income settings. This study provides the first class-level pharmacovigilance analysis from a South Asian tertiary hospital, generating safety signals across 84 drug subclasses and evaluating concordance between Proportional Reporting Ratio (PRR) and Reporting Odds Ratio (ROR) methods. Methods: We conducted a retrospective cross-sectional analysis of electronic health records (2018-2022), comprising 718,088 drug administration events. Adverse drug reactions (ADRs) were identified using ICD-9-CM/ICD-10-CM codes. Disproportionality analyses using PRR and ROR were applied to each subclass. Results: PRR identified positive signals in 5 subclasses, while ROR identified 7. The seven high-risk subclasses included antitubercular agents (PRR 3.24; ROR 4.14), anesthetic muscle relaxants (2.44; 2.84), aminoglycosides (2.24; 2.55), immunosuppressants (2.19; 2.47), neurologic sedatives (2.06; 2.29), antineoplastic cytotoxic agents (1.95; 2.15), and general anesthetic agents (1.88; 2.06). Concordance between PRR and ROR was high (96.4% agreement; κ ≈ 0.80; McNemar Conclusion: This analysis establishes baseline class-level risk estimates in a developing pharmacovigilance environment, identifies disproportionately high-risk drug classes, and supports the robustness of PRR and ROR as complementary screening tools for regional drug safety monitoring.