Merits of using color and shape differentiation to improve the speed and accuracy of drug strength identification on over-the-counter medicines by laypeople.

OBJECTIVE: This study aimed to examine the utility of using color and shape to differentiate drug strength information on over-the-counter medicine packages. Medication errors are an important threat to patient safety, and confusions between drug strengths are a significant source of medication error. METHOD: A visual search paradigm required laypeople to search for medicine packages of a particular strength from among distracter packages of different strengths, and measures of reaction time and error were recorded. RESULTS: Using color to differentiate drug strength information conferred an advantage on search times and accuracy. Shape differentiation did not improve search times and had only a weak effect on search accuracy. CONCLUSIONS: Using color to differentiate drug strength information improves drug strength identification performance. Color differentiation of drug strength information may be a useful way of reducing medication errors and improving patient safety.