Pharmacogenomics and Personalized Medicine: Translating Genetic Variation into Precision Therapeutics

Interindividual variability in drug response represents a persistent challenge in clinical pharmacology, contributing to therapeutic failure and adverse drug reactions (ADRs) in a substantial proportion of patients. Pharmacogenomics, the study of how genomic variation influences drug disposition and effects, has emerged as a transformative discipline bridging pharmacology and genomics.This review synthesizes contemporary evidence regarding the principles, clinical applications, technologies, and implementation frameworks of pharmacogenomics within the broader context of personalized medicine. Genetic polymorphisms affecting pharmacokinetic and pharmacodynamic pathways—particularly within cytochrome P450 enzymes, thiopurine methyltransferase, dihydropyrimidine dehydrogenase, and human leukocyte antigen loci—demonstrate robust associations with drug efficacy and toxicity. Regulatory agencies including the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have incorporated pharmacogenomic biomarkers into drug labeling, while the Clinical Pharmacogenetics Implementation Consortium (CPIC) and the Dutch Pharmacogenetics Working Group (DPWG) have issued actionable dosing guidelines for numerous gene-drug pairs. Despite compelling evidence, the transition from research to routine clinical practice remains heterogeneous globally, impeded by economic barriers, educational gaps, and ethical complexities surrounding genetic data.The integration of artificial intelligence, multi-omics platforms, and digital health infrastructure promises to accelerate pharmacogenomic adoption, yet successful implementation requires harmonized regulatory standards, equitable access across diverse populations, and systematic healthcare professional education. Pharmacogenomics stands poised to fundamentally redefine therapeutic paradigms, shifting from empirical prescribing to genotype-directed precision medicine.