Author Affiliations: Departments of Psychiatry and Pediatrics, Mayo Clinic College of Medicine, Rochester, Minnesota (Dr Mrazek); and Department of Psychiatry and Abramson Cancer Center, University of Pennsylvania, Philadelphia (Dr Lerman).
Variability in drug response can be explained, in part, by genetic differences among patients. A clear role in drug toxicity and efficacy has been established for some gene-drug combinations, yet implementation of pharmacogenomic tests in clinical practice lags behind this knowledge. The evidence – adoption gap for many pharmacogenomic tests can be addressed in the short term through the development of consensus-based practice guidelines and clinician education.
For genetic variants associated with severe drug toxicities, there is a strong impetus for adoption. An example is the HLA-B*15:02 variant, associated with the potentially lethal Stevens-Johnson syndrome in Asian patients treated with carbamazepine.1 Another example is the poor metabolizers of cytochrome p450 2D6 substrates that represent a range of risk when exposed to specific medications. The death of a child treated with fluoxetine illustrates the importance of identifying patients with impaired metabolism as well as the ethical dilemma of knowingly exposing patients with minimal metabolic capacity to substrates that require a specific enzyme for clearance.2
Mrazek DA, Lerman C. Facilitating Clinical Implementation of Pharmacogenomics. JAMA. 2011;306(3):304-305. doi:10.1001/jama.2011.1010