What's in the Black Box?

Researchers find inconsistencies in black box warnings

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) In a new study, researchers from Greece and the U.S. call attention to inconsistencies in black box warnings - the safety warnings on a drug's label that highlight the serious risks of that drug.

Generally, the most serious side effects of a drug will be the same for the entire category of that drug. As such, black box warnings often apply to most or all of those categories, rather than one specific drug.

In order to see if black box warnings were uniform across drugs in the same class, a team of researchers from the University of Ioannina School of Medicine in Greece and Stanford University School of Medicine examined the labels of 20 top-selling drug classes. The researchers, led by Orestis Panagiotou and John Ioannidis, also investigated if there were differences in the time it took to add a warning to drugs from the same class.

The researchers found differences in 9 of the 20 categories. These differences involved 15 black box warnings that were not on all the labels of drugs in the same class.

The problem with differences in black box warnings is the inconsistency of the differences. In 10 of the 15 different warnings, the researchers found that the information normally included in the black box warning was places elsewhere on the label in a less prominent place. For the other 5, the black box information was not included at all.

Such inconsistencies are not inherently a problem. However, the authors argue that a label should indicate why a risk common to a whole class of drugs is not a risk for one specific drug in that class.

Adding to these inconsistencies, the researchers found that black box warnings of some drugs took as long as 14 years to be added to the labels of drugs in the same class.

Such a delay can lead to serious problems. Case in point: a French Parkinson's patient who was prescribed Requip® for tremors turned into a gambling and sex addict, eventually leading to his rape and a loss of his family's savings. His gambling and sex addictions ended as soon as he stopped taking the drug in 2005. According to the man's lawyers, the manufacturer of Requip®, GlaxoSmithKline, knew of these possible side effects for years, but did not add a warning to the label until 2006.

According to the study's authors, these labeling inconsistencies suggest a need for systematic and transparent rules to guide the process of black box warning labels.

The study appears in the Journal of General Internal Medicine.

Reviewed by: 
Review Date: 
February 2, 2011
Last Updated:
February 3, 2011