Information overload in drug side effect labeling

The lists of potential side effects that accompany prescription drugs have ballooned in size, averaging 70 reactions per drug, a number that can overwhelm physicians trying to select suitable treatments for their patients, according to a new study of drug labels.

Long lists of drug side effects - whether found in magazine advertisements or in package inserts - are a familiar sight to patients and doctors. Now researchers from the Regenstrief Institute and the Indiana University School of Medicine, both based in Indianapolis, have quantified just how complex drug labels have become.

In the study, appearing in the May 23 issue of the Archives of Internal Medicine, the researchers found that the average label contains 70 different side effects, with more commonly prescribed drugs averaging around 100 side effects. The upper range was remarkably high, with a single label containing as many as 525 reactions. The study involved analysis of more than 5,600 drug labels and more than half a million labeled effects.