Retrospective Analysis of Adverse Drug Reactions From a Teaching Hospital in South India: Patterns, Severity, Causality, and Preventability

Background and aim: An adverse drug reaction (ADR) is a response to a medicinal product that is noxious and unintended, and that occurs at doses normally used in humans for the prophylaxis, diagnosis, or treatment of disease, or for the restoration, correction, or modification of physiological function. This study aimed to analyze ADRs retrospectively to assess the patterns, severity, seriousness, causality, and preventability of adverse drug reactions (ADRs) reported to an ADR monitoring center. Materials and methods: All suspected ADRs reported from January 2020 to December 2024 to an ADR monitoring center at Sri Manakula Vinayagar Medical College and Hospital, Puducherry, which is a 1,121-bed hospital, were identified. The study period was from January 2025 to April 2025. A retrospective analysis was conducted of the clinical presentation, ADR seriousness, severity, causality, and preventability. Results: Out of 139 ADRs reported, the majority (n=102 {73.3%}) occurred in patients aged 19-65 years, with a female predominance (n=84 {60.4%}). The most commonly affected body system was skin and subcutaneous tissue (n=93 {66.9%}), followed by general disorders (n=23 {16.5%}). The most commonly reported causal drug classes were antimicrobials (n=79 {56.8%}), followed by non-steroidal anti-inflammatory drugs (NSAIDs) (n=11 {7.9%}) and vitamin supplements (n=11 {7.9%}). Causality assessment showed (n=2 {1.4%}) certain, (n=127 {91.4%}) probable, and (n=10 {7.2%}) possible. Severity assessment showed the majority (n=124 {89.2%}) of reported ADRs were moderate, followed by mild (n=9 {6.5%}). The majority of ADRs were non-preventable (n=135 {97.1%}), followed by (n=4 {2.9%}) being definitely preventable. Conclusion: Antimicrobials contributed to the majority of ADRs, with most reactions being probable in causality, moderate in severity, and largely non-preventable. Skin and subcutaneous tissue were the most frequently affected organ systems. Under-reporting of ADRs is suspected in our study. Our study highlights the need for vigilant monitoring during antimicrobial therapy and strengthening pharmacovigilance practices to facilitate early detection, appropriate management, and reporting of ADRs, thereby enhancing patient safety.