Warfarin Pharmacogenetics: Ready for Clinical Utility?(Clinical PRACTICE‪)‬

Despite the Federal Drug Administration's August 2007 relabeling of warfarin to recommend pharmacogenetic (PGx) testing, the clinical application remains controversial. Many questions exist regarding how information gleaned from genetic testing can be applied in warfarin therapy. In particular, does PGx testing lead to a shorter time to stable INR compared to prudent international normalized ratio (INR) monitoring coupled with the consideration of age, BMI, diet, and physical condition? Does it reduce clinical complications? Other topics of uncertainty include whether the correct warfarin dose can be obtained based on genotype, whether PGx testing is cost-effective, and turn-around-time. Despite the reservations about warfarin PGx testing, there are several subsets of patients for whom such testing could be beneficial. BACKGROUND