Drug Metabolism

Pharmacogenomics, an interdisciplinary basis of personalized medicine, explains the influence of genomic variation on drug disposition, response, and toxicity. Pharmacogenomics is exemplified in both mechanistic and clinical concepts, demarcating its crossing point between pharmaceutical and biomedical sciences. Polymorphisms in drug-metabolizing enzymes (e.g., CYP2D6, CYP2C9, CYP2C19), transporters (e.g., ABCB1, SLCO1B1), and pharmacologic targets (e.g., VKORC1, EGFR) alter pharmacokinetic and pharmacodynamic profiles, making justifications for individualized therapeutic strategies. The paper defines the pharmacogenomic uses in oncology, cardiology, and psychiatry fields for which pharmacogenomic markers (e.g., HER2, KRAS, CYP2C19) are now a requirement to maximize the effect of treatment and minimize drug reactions. The review also points towards the pivotal role of allied biomedical sciences—i.e., human physiology, clinical biochemistry, and molecular diagnostics to locating gene–drug interactions within the frame of everyday clinical phenotypes. Despite the great leaps, clinical translation remains beset by issues such as fragmentation of regulation, bioethics, population-specific gaps in data, and a lack of clinical genomic literacy. Technologies in the form of next-generation sequencing, multi-omics fusion, and artificial intelligence-based decision support systems, however, offer the potential for scalable and equitable deployment. In summary, pharmacogenomics is a paradigm shift towards genotype-directed pharmacotherapy. For its successful incorporation in clinical medicine, interdisciplinary collaboration, strong informatics support, and harmonized regulatory policies need to supply rational, safe, and personalized drug therapy.