Pharmacogenetics

Pharmacogenetics is the study of the genetic determinants of drug response variability. Some pharmacogenetic tests can be used to explain or predict adverse events and/or non-responsiveness to therapy. The goal and promise of clinical pharmacogenetic testing is to deliver the right drug to the right person at the right dose. As such, when a genetic variant directly involved in drug response variability is identified in a patient prior to initiating therapy, adverse reactions, excessive use of ineffective drugs, or ineffective dosing can hopefully be prevented. Despite challenges to demonstrate clinical utility, clinical tests are currently available for selected genes where clinical validity has largely been established. This chapter describes pharmacogenetic applications for which clinical tests are currently available, including CYP2D6, CYP2C19, CYP2C9 and VKORC1, TPMT, and UGT1A1.