Blog | Thursday, June 2, 2011

QD: News Every Day--Drug labels overwarn about adverse events, even confuse doctors


Drug labels warn about a mean of 70 adverse events per medication, leading researchers to conclude that the glut of information is confusing patients.

Jon Duke, MD, an ACP Member, and other researchers extracted 534,125 adverse drug events from 5,602 product labels. There was a mean of nearly 70 events per label. They found 588 with more than 150 adverse drug events and 84 with more than 300, with the top offender having 525 events listed. This top group included selective serotonin reuptake inhibitors, anti-virals, and restless leg syndrome drugs.

Labels for the 200 most commonly dispensed medications contained significantly more adverse drug events than others (median, 79 vs. 47; P<.001). By specialty, there were more adverse drug events listed in the fields of neurology (n=168), psychiatry (n=116), and rheumatology (n=111).

Drugs approved during the 1980s and 1990s had the highest overall number of adverse drug events, while newer medications had significantly more labeled adverse drug events than older medications.

"The findings aren't unexpected," wrote Dr. Duke and colleagues in the Archives of Internal Medicine. Newer drugs face more rigorous clinical trials and postmarketing surveillance than older medications. More commonly prescribed drugs are more likely to generate more reports of adverse events. The high volume of events in neuropsychiatric medications "may relate as much to patient population as to the effects of the drugs themselves."

But, Dr. Duke and colleagues concluded, "The presence of such excess data still may induce information overload and reduce physician comprehension of important safety warnings."

While the Food and Drug Administration tried to revamp warning labels in 2006, labels have grown more complex since then. "This finding underscores the tremendous challenge faced by the FDA in reversing the long-standing trend toward overwarning."