Analyzing the Impact of Drug Name Similarity on Dispensing Errors: An Examination Using a Drug Name Similarity Index.

Dispensing errors pose a significant health risk, with drug name similarity being a potential contributory factor. To determine the impact of drug name similarity on dispensing errors within clinical settings, we analyzed 563 dispensing errors at an acute hospital in Japan from April 2015 to June 2018. Drug name similarity between two drugs was classified into Name-Similar and Name-Dissimilar groups using the m2-vwhtfrag index, the value of the drug name similarity. Drug efficacy similarity was categorized into Efficacy-Same, Efficacy-Close, and Efficacy-Far. The drug name similarity and drug efficacy similarity of all possible pair combinations were obtained and similarly classified. The proportion of the number of pairs with dispensing errors per the total number of drug pairs in the hospital's drug formulary in each category was calculated. The highest proportion of the number of pairs with dispensing errors was 36% for the Efficacy-Same and Name-Similar group, and the lowest proportion was 0.022% for the Efficacy-Far and Name-Dissimilar group. The proportion of the number of pairs with dispensing errors was significantly higher in the Name-Similar category than in the Name-Dissimilar category for all drug efficacy categories. Our results indicate that drug name similarity increases the risk of dispensing errors, and that m2-vwhtfrag is a useful indicator to assess dispensing errors in clinical practice. Such drug name and efficacy similarity evaluations can help identify factors causing dispensing errors, and predict the risk of dispensing errors for newly adopted drugs, considering the relationship with the whole drug formulary in the hospital dispensary.