title: Mechanism of isoniazid-induced hepatotoxicity: then and now.
abstract: Isoniazid (INH) remains a mainstay for the treatment of tuberculosis despite the fact that it can cause liver failure. Previous mechanistic hypotheses have classified this type of drug-induced liver injury (DILI) as 'metabolic idiosyncrasy' which was thought not to involve an immune response and was mainly due to the bioactivation of the acetylhydrazine metabolite. However, more recent studies support an alternative hypothesis, specifically, that INH itself is directly bioactivated to a reactive metabolite, which in some patients leads to an immune response and liver injury. Furthermore, there appear to be two phenotypes of INH-induced liver injury. Most cases involve mild liver injury, which resolves with immune tolerance, while other cases appear to have a more severe phenotype that is associated with the production of anti-drug/anti-CYP P450 antibodies and can progress to liver failure.
authors.affiliation: Center for Advanced Laboratory Medicine, Department of Pathology, University of California San Diego, San Diego, CA, 92116, USA.
authors.forename: Imir
authors.initials: I
authors.lastname: Metushi
authors.affiliation: Leslie Dan Faculty of Pharmacy, Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2, Canada.
authors.forename: Jack
authors.initials: J
authors.lastname: Uetrecht
authors.affiliation: Department of Medicine, Vanderbilt School of Medicine, Nashville, TN, 37232, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Phillips
mesh_terms: D000995:Antitubercular Agents / Q000009:adverse effects / Q000493:pharmacokinetics; D001711:Biotransformation; D056486:Chemical and Drug Induced Liver Injury; D006801:Humans; D007538:Isoniazid / Q000009:adverse effects* / Q000493:pharmacokinetics*
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid
keywords: biomarker; hepatotoxicity; immune mediated; reactive metabolite; tolerance