[Survey of difference in appearance between multiple-specifications press-through-package drug products and an...

To survey the difference in appearance between multiple-specification press-through-package (PTP) drug products and to attempt to evaluate their effectiveness as discriminating factors based on dispensing incidents. Front and back sides of, respectively, 153 and 134 PTP drug products of multiple specifications stockpiled in the author's pharmacy were surveyed for differences in wording and appearance between specifications of the same type of drug. Fifty six dispensing incidents with 40 sets occurred over a year and they were analyzed for the appearance similarity of the front side. The difference factors detected in the 40 sets of "mix-ups" were also reviewed after similarity-omitted counting. We identified six factors with difference in appearance: color-related (letter front or patterns, sheet, medicine) and shape- or pattern-related details (sheet and medicine sizes, patterns). Multiple differences on the front packaging of the same type of drug were identified in 93% of the sets, while only one difference was found in about half of the sets on the back, indicating that pharmaceutical companies placed more emphasis on the front side to discriminate their features. When reviewed by similarity-omitted counting, the ratio of sets with only one difference in the 40 mix-ups was higher than those to 128 sets of non-mix-ups, the total sets except the mix-ups, while the ratio of sets with two differences was lower. In addition, the ratio of sets in which only color-related factors differed in the 40 mix-ups was higher than that in the corresponding category to the 128 sets of non-mix-ups. Various discriminating factors were used in combination on the front side of multiple-specification PTP drug products. A combined use of shape- or pattern-related and color-related factors probably reduces dispensing incidents among products with multiple specifications. However, further accumulation of incident data and multifactor analysis of those data seem necessary to clarify the function of difference in appearance in dispensing incidents.