Trends in reporting drug-associated liver injuries in Taiwan: a focus on amiodarone

Background A pharmacovigilance database of real-world adverse drug reaction (ADR) reports is helpful for characterising adverse events and identifying new signals after drug approval. Objective This study aimed to analyse trends of ADR reporting in relation to liver injury and to delineate critical factors for suspected drug-related hepatotoxicity with a focus on reports associated with amiodarone. Setting The 2000-2014 Taiwan pharmacovigilance database. Method Relevant Standardized Medical Dictionary for Regulatory Activities queries were used to identify reports associated with liver injury. Information on ADR, patient characteristics, and the verbatim pertaining to amiodarone prescriptions, liver injury, comedications, and comorbidities were extracted and evaluated. Group comparisons between Hy's Law cases and Temple's Corollary cases of suspected amiodarone-related hepatotoxicity were performed. Main outcome measure Number and nature of drug-related liver injuries, particularly those associated with amiodarone. Results Of the 98,777 ADR reports over a 15-year period, 4261 (4.3%) were related to liver injury. Sixty-eight reports contained amiodarone prescriptions, but only 49 (1.1%) were eligible for further analysis. Hepatotoxic cases associated with amiodarone mostly occurred within 1 week, exhibited a hepatocellular pattern, and were more common among elderly individuals. Among 23 discernible cases, four (17.4%) recovered fully from liver injury. The critical Hy's Law cases were associated with shorter height, lower body surface area, and higher average daily doses. Conclusion This study substantiates the importance of ADR reporting. Data pertaining to drug-associated liver injury and factors associated with suspected amiodarone-related hepatotoxicity warrants continual attention in pharmacovigilance for those at risk, especially the elderly.