Pharmacogenomics is a branch of pharmacology concerned with using DNA and amino acid sequence data to inform drug development and testing. An important application of pharmacogenomics is correlating individual genetic variation with drug responses.
Pharmacogenomics is a combination of two fields and two different words: "pharmacology" and "genomics". So what that refers to is differences in different people's genomes, which result in differences in their pharmacology. Or in other words, the way they respond to a drug, because that is what pharmacology is. So pharmacogenomics is used in many ways. It's used most commonly to ask whether different people who have slightly different genomes, that is, the sequence of one gene or another, is different from one person or another. Is that going to influence their response to a drug, either in a positive way--that is, will one person get a therapeutic effect from a drug and the other person not--or in a bad way--that is, is one person going to get a side effect from a drug and the other one won't--as a result of that difference in the DNA sequence?- Christopher P. Austin, M.D.