Side Effects: Genes and Medicines
Medicines that work wonders for you can be ineffective—or even harmful—to others. Why? Age, weight, lifestyle and other medicines each play a role, but so do genes.
Scientists use computers to find the specific genetic variations that affect the way we respond to drugs. This field of research is called pharmacogenetics, and its goal is to determine the type and dose of medicine best suited for each individual.
Geneticist Gary Peltz at Roche Palo Alto in California leads one research team working in this field. His group has looked for tiny differences that change how mice process, or metabolize, the drug warfarin.
Nearly 2 million Americans, especially those who have heart disease or are recovering from major surgery, take warfarin to prevent deadly blood clots. But warfarin is tricky to prescribe. Too much causes excessive bleeding and too little could allow clots to form. Doctors use a careful, trial-and-error approach to find the right amount for each person.
The California researchers pinpointed the gene that makes an enzyme the mice need to metabolize warfarin. Searching with computers, they then found slight variations in the gene's DNA that could influence how quickly the animals eliminated the drug from their bodies. The scientists were able to use the mice's genetic profiles to predict how the mice would process the drug. Similar studies in humans could ultimately help doctors more quickly and precisely prescribe the right dose of warfarin.