Drug Hepatotoxicity

Abstract

Idiosyncratic drug-induced liver injury (DILI) caused by xenobiotics (drugs, herbals, and dietary supplements) is an elusive liver disease presenting with a range of phenotypes and severity, including acute hepatitis that is indistinguishable from viral hepatitis, autoimmune hepatitis, steatosis, fibrosis or rare chronic vascular syndromes, asymptomatic liver test abnormalities,and acute liver failure. Case definition and characterization using liver biochemistry and histology are crucial for appropriate phenotyping. The incidence of DILI is probably higher than expected by the cases that are identified in clinical practice because of misdiagnosis and underreporting.The pathogenesis of DILI is complex, depending on the interaction of a drug’s physicochemical properties and host factors. Genome-wide association studies have identified several alleles from the major histocompatibility complex system, indicating a fundamental role of the adaptive immune system in DILI pathogenesis. As specific biomarkers for hepatotoxicity are still not available, the diagnosis of DILI remains one of exclusion of the alternative causes of liver damage. Structured causality assessment using the Roussel Uclaf Causality Assessment Method (RUCAM) or previously Council for International Organizations of Medical Sciences (CIOMS) instrument adds consistency to the diagnostic process, although there is room for improvement in the scale domains and score weighting. The therapy for idiosyncratic hepatotoxicity is supportive and relies on the prompt withdrawal of the offending agent. Corticosteroid therapy for hypersensitivity reactions or ursodeoxycholicacid for prolonged cholestasis is empirically used, although the degree of evidence is low. Existing databases have enabled a better prediction of immediate and long-term DILI prognosis. Multivariate models have identified clinical and analytical variables as predictive of acute liver failure and mortality as well as of chronic DILI. This review contains 2 figures, 5 tables, and 55 references Key Words: adaptive immune system; causality assessment; drug-induced liver injury; epidemiology; HLA alleles; pharmacogenetics; registries; risk factors