Individualized Medicine: What Pharmacogenetics Will Mean to Your Practice

Medical recommendations driven by a patient’s inborn ability to efficiently utilize specific drugs are quickly becoming mainstream practice. The term “pharmacogenetics ” is defined as the study of genetic causes of individual variation in drug response. The knowledge of which genes and their polymorphisms, or variations, adversely affect drug metabolism is proliferating. The clinical utility of CYP2D6 genetic testing to determine a patient’s predicted response to tamoxifen has been demonstrated, which has led some insurance providers to request this testing prior to2,3,4,5,6 administration of the drug or renewal of a prescription. This article aims to summarize the current information and application of this technology, primarily using tamoxifen as an example, as well as future directions and implications. It has been long understood that many genes manufacture enzymes that help to metabolize everything people ingest, from food to medications. Individual variation in drug metabolizing capacity is a complicating factor in the efficacy of cancer treatment regimens. Research has focused on understanding which genes are the most crucial in metabolizing commonly-used drugs and chemotherapeutic agents, as well as which variants within these genes predispose to decreased metabolic potential. For example, if a patient is known to carry a genetic variant that predisposes he