Interconnected Metabolic and Cellular Pathways in Drug-Induced Hepatotoxicity: Translational Safety Implications

Drug-induced liver injury remains a principal trigger of acute hepatic failure, late-stage drug attrition, and post-marketing withdrawal, reflecting persistent limitations in mechanistic prediction and translational safety assessment. Owing to its central role in xenobiotic biotransformation, the liver is highly vulnerable to metabolic bioactivation and reactive intermediate formation. This review presents a metabolism-centered; systems level framework that integrates Phase-I and Phase-II enzymatic processes with downstream cellular stress responses governing hepatocellular fate. Cytochrome 450-mediated oxidation and subsequent conjugative pathways determine the balance between detoxification and electrophilic burden; disruption of this equilibrium initiates oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, bile-acid transport impairment, immune-inflammatory activation, and regulated cell death. Emphasis is placed on the dynamic crosstalk among these pathways, which explains interindividual variability, idiosyncratic susceptibility and preclinical-clinical discordance. Emerging insights from network toxicology, transcriptomics, metabolomics and computational modelling have enhanced mechanistic resolution beyond conventional biomarkers. Concurrently, advanced experimental systems including three-dimensional hepatic cultures, organoids, micro-physiological liver-on-chip platforms, humanized animal models and integrative in vitro-in silico approaches are improving translational fidelity. Collectively, this synthesis advances a cohesive mechanistic perspective and highlights integrative strategies to strengthen early risk stratification, mechanistically informed evaluation and predictive safety assessment in drug development.