Meaningful Use and Clinical Utility of Preemptive Pharmacogenetic Testing: (Re)View From a CYP2D6 Poor Metabolizer

The value of pharmacogenetic information at an individual level seems self‐evident; demonstrating the value to the individual across a population appears to be much more difficult to demonstrate. Future studies should avoid single gene–drug pairs and a limited number of population‐specific alleles that are insufficient to capture all relevant genetic variation within diverse populations, such as CYP2C9*2 and *3. Robust associations between cytochrome P450 (CYP) genotypes and treatment response require knowledge of drug exposure.