pharmacogenomics

Why does the same medicine, at the same dose, help one person, do little for another, and cause side effects in a third? Pharmacogenomics looks for part of the answer in our genes. It studies how inherited differences shape the way each body absorbs, activates, and clears a drug.

Much of the action lies in genes for drug-metabolizing enzymes. A variant that makes an enzyme fast can break a drug down before it works; one that makes it slow can let the drug build up to toxic levels. Other genes affect the drug’s target or the chance of dangerous reactions.

The practical promise is more precise prescribing: choosing the right drug and dose for a given person’s genetic makeup, rather than trial and error. The reality is that genetics is one factor among many — age, organ function, diet, and other medicines all matter too.