Characteristics, preventability, management, and predictors of adverse drug reaction-related hospital admissions: a cross-sectional study in a Thai tertiary care hospital

Background Adverse drug reaction (ADR)-related hospital admissions may be fatal and increase substantial healthcare costs, but several ADRs are preventable. However, studies on preventable ADRs in Thailand remain limited, particularly with respect to their management and prevention. Aim To determine the frequency, characteristics, and preventability of ADR-related hospital admission, and to evaluate the management, prevention strategies, and associated factors.Methods A cross-sectional study was conducted among patients admitted to a tertiary care teaching hospital. Data were extracted from the hospital’s medical record database for a 9-month period. ADR-related hospital admissions were identified using the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10).Results During the study period, 29,927 patients were admitted to the hospital. Of these, 730 admissions were identified as ADR-related based on ICD-10 codes, and 200 patients were included using purposive sampling. The most frequently reported ADRs involved cardiovascular disorders (50.5%), and nervous system disorders (17.0%). The most common suspected drugs were warfarin (38.0%) and paracetamol (5.0%). Approximately 67.1% of ADRs were classified as probable or definite, and 66.0% were considered preventable. The primary management strategy was discontinuation of the suspected drug (82.5%), while discharge counselling was the most commonly employed preventive measure (56.0%). Inappropriate dosage was independently associated with the preventability of ADR-related hospital admissions (OR 0.007; 95% CI 0.001–0.074; p < 0.001), and age groups of 36–65 years and more than 65 years were independently associated with documented ADR-related hospital admissions (OR 7.688; 95% CI 1.533–38.548; p = 0.013 and OR 9.441; 95% CI 1.668–53.422; p = 0.011, respectively).Conclusions Warfarin was the most frequently implicated drug in ADR-related hospital admissions. Inappropriate dosing was significantly associated with preventable ADR-related hospitalisations. Implementing targeted strategies, such as dose optimisation and appropriate clinical monitoring, may enhance medication safety and reduce preventable ADRs.