The terms pharmacogenomics and pharmacogenetics are often used interchangeably to describe a field of research focused on how genes affect individual responses to medicines. Whether a medicine works well for you—or whether it causes serious side effects—depends, to a certain extent, on your genes.
Just as genes contribute to whether you will be tall or short, black-haired or blond, your genes also determine how you will respond to medicines. Genes are like recipes—they carry instructions for making protein molecules. As medicines travel through your body, they interact with thousands of proteins. Small differences in the composition or quantities of these molecules can affect how medicines do their jobs.
These differences can be due to diet, level of activity, or the medicines a person takes, but they can also be due to differences in genes. By understanding the genetic basis of drug responses, scientists hope to enable doctors to prescribe the drugs and doses best suited for each individual.