Objective: Taking the wrong medicine or medication error is a serious concern to patient safety.  The aim of this study was to statistically survey the relation between the placement of drugs on medicine shelf and the occurrence of error in taking a medicine.
Methods: The study comprised 2 groups.  The incident group contained 43 cases that were erroneously taken in the Obihiro Kosei General Hospital.  The control group contained 43 drug pairs matched by the similarity index of the drug names from among the drugs used in the hospital at random.  The similarity index of drug names was based on 10 quantitative indicators.  The distance of medicine shelf arrangement was represented by three variables: the horizontal distance, the vertical distance and the distance of shelf block.  Conditional logistic regression analyses of the occurrence of medication errors were performed by evaluating the three variables of the distance factor and their interaction for error in taking a similar-sounding named drugs.
Results: Conditional logistic regression analysis revealed that the vertical distance (OR: 0.64, 95%CI: 0.42-0.99) and the distance of the shelf block (OR: 0.74, 95%CI: 0.57-0.97) were significant risk-reduction factors of medication errors.  Four variables were extracted as the most suitable logistic regression model in terms of the interaction between them.  As the interaction between 3 variables (the horizontal distance, the vertical distance and the distance of shelf block) was significant (OR: 0.93, 95%CI: 0.86-0.99), they may be considered as synergistic risk-reduction factors.  Moreover, the horizontal distance was found to be a risk-enhancement factor (OR: 1.52, 95%CI: 0.93-2.48).
Discussion: In order to reduce the risk of medication errors due to similar-sounding drug names, placement of drug on the medicine shelf should take into consideration the three coordinates of the distance factor.

1) We found that students of the Graduate Entry Program (GEP) had the will to realize the aim of the recruitment but did not think highly of the GEP and were not highly motivated to contribute to medicine, the school, or the region. These findings reflect their low self-evaluation and their lack of real activities.
2) The GEP students had various proposals about the recruitment and examination methods of the GEP. Most proposals request clarification of how the program fits into the university's future goals.
3) Many GEP students foresaw that 5 to 10 years would be needed to distinguish themselves to from non-GEP students. At that time, more extensive research on GEP should be conducted.