The field of pharmacogenetics, which is about 40 years old, is the study of genetically determined variability in the response of individuals to drugs. Much of the research in this area has focused on genetic variations affecting hepatic metabolizing enzymes, particularly the CYP450 family. [wp_ad_camp_4]Pharmacogenetics attempts to identify those individuals within the population who are susceptible to possible alterations in drug metabolism so that this may be taken into account during development of a therapeutic regimen. The ability to identify hereditary differences in metabolism allows drugs to be prescribed in a more efficacious and safe manner to begin with, without having to adjust dosage after observing an undesired patient response. Many pharmacogenetic studies have explained drug idiosyncrasy, which is the abnormal response to a drug in a few patients, resulting in serious toxicity. Most idiosyncratic reactions are now known to arise because of genetic variation in metabolizing enzymes.
Although the field of pharmacogenetics began with a focus on drug metabolism, it now encompasses the entire spectrum of drug disposition, including a growing list of transporters that influence drug absorption, distribution, and excretion.