The terms pharmacogenomics an pharmacogenetics tend to be used interchangeably, and a precise, consensus definition of either remains elusive. Pharmacogenetics is generally regarded as the study or clinical testing of genetic variation that gives rise to differing response to drugs, while pharmacogenomics is the broader application of genomic technologies to new drug discovery and further characterization of older drugs. Pharmacogenetics considers one or at most a few genes of interest, while pharmacogenomics considers the entire genome.