Just as genes determine the color of our eyes and our hair, they also affect our response to medication. Different individuals can have different variations of a single gene.
Each DNA copy has slight differences, some of which are common and some are rare. In addition, some of them have certain effects on health, for instance, genes related to certain diseases.
Pharmacogenomics studies the effect of genes on drug response. The long term goal is to help physicians select the most effective drug with the least side effects for each individual.
In actuality, pharmacogenomics can play an important role in finding individuals which response or do not response to medication, which can reduce side effects and help prescribe optimal dosage.
 Omics technologies can contain massive quantities of data which require considerable analysis.
Pharmacogenomics research use genomic, transcriptomics, and proteomics and metabolomics information to identify genes related to drug response in medication used for cancer, mental disorders, etc.
Although this field is on its early days with limited application, pharmacogenomics will allow healthcare providers to prescribe a wide range of medication to combat certain diseases such and Alzheimer's, Cardiovascular diseases, HIV/AIDS, and asthma. 

More ...