Pharmacogenetics is the study of how INDIVIDUAL is responding in their own way to drug therapy established upon their genetic arrangement or genes. Name itself reflects its meaning linking of pharmacology and genomics. Pharmacogenomics examines how the genetic design or arrangement of an individual affects his/her reaction to drugs.The term pharmacogenetics has been in use since 1959.1 Pharmacogenetics was first utilized in reference to phenotypic variation in metabolism and response to certain drugs. This was well established to be a standard phenomenon within the case of some drug treatments by the top of the 1950s.2–4 After only limited progress within the 1960s and 1970s, a mixture of improved analytical methods, more extensive drug development programmes and human gene cloning resulted within the genetic basis of this phenotypic variation becoming far better understood during the 1980s.