Not Yet Ready for Prime Time, but Getting There

There are few, if any, situations in medicine in which aclinician can predict with certainty an individual’sresponse to drug therapy. A host of factors can modulate this response: concomitant disease or drug therapy, sex, age, ethnicity, or dysfunction of excretory organs, to name but a few. Even when we correct for changes antici-pated by such conditions, however, drug responses remain highly variable. It is an appealing concept, and one to which we subscribe, that some portion of this variability—and perhaps a great portion in many cases—is attributable to genetic factors. An increasingly sophisticated view of the genetic determinants of drug action in the context of complex diseases now raises the realistic expectation that this possi-bility can be addressed. See p 1644 The Present Study In this issue of Circulation, McNamara and colleagues