A continuing black hole? The FDA boxed warning: an appeal to improve its clinical utility.

The boxed warning is increasingly utilized by the Food and Drug Administration (FDA) as a clinical warning to prescribers of dangerous adverse drug reactions. As these warnings have expanded, we feel the utility and application of boxed warnings are becoming more nebulous. The use of drugs following issuance of a boxed warning has been variable. Droperidol sales decreased 10-fold in the year following the warning, yet there has been essentially no change in the methadone usage over a similar time period after its boxed warning. Including more information, such as estimation of incidence for the adverse drug reaction, would be more clinically useful to the prescriber. Reasonable standards using supplemental databases outside of the FDA (such as national poison center data) could be helpful in developing an integrated and balanced approach to boxed warnings.