Effect of package label characteristics on pharmacists' visual perception of drug names

To highlight portions of a drug name that might be confused with other similar drug names, manufacturers use a variety of different stylistic label formats (e.g., bolding, italics, highlighting, underling, capitalization) on primary package labels of prescription drugs. Two experiments were conducted with pharmacists as participants to determine whether two high occurrence label formats (letter bolding and the use of mixed case text) had an impact on pharmacists' accuracy and reaction time in a speeded same-different judgment task. Both experiments examined the effect of orthographic similarity between drug names and stylistic label format (bolding and mixed case text) on accuracy and reaction time. Experiment 2 also examined the effect on accuracy and reaction time of the specific location of the stylistic format within the drug name. The results of both experiments highlighted the strong effect of orthographic similarity on accuracy and reaction time of pharmacists. Pharmacists were less accurate and exhibited longer reaction times when the drug names were orthographically similar. Mixed case text did not significantly impact accuracy or reaction time in either experiment despite the growing belief that these text enhancements reduce dispensing errors. The placement of the text enhancement within the drug name did not significantly effect accuracy or reaction time of pharmacists. Given the relatively high frequency various label formats are recommended by regulators and safety related institutions, it is important the pharmaceutical manufacturers and regulators implement evidence based models to establish regulatory policy related to package labeling. Clear regulatory policy based on rigorous scientific data will help ensure the use of any package label format to mitigate name confusion will provide the greatest patient safety benefit.