How specific are "target-specific" drugs? Celecoxib as a case in point

With the push to develop the next blockbuster drugs, continued surveillance of current bestsellers may not be given the full attention due. Upon wide-spread use, unexpected adverse effects begin to emerge. Although touted as highly specific, many of the newly developed drugs are likely to have secondary molecular targets-a potential cause of adverse effects. A molecular pharmacology approach that screens for multiple drug targets may shed light on the mechanisms that underlie both desired and adverse side-effects.