[Longer working hours of pharmacists in the ward resulted in lower medication-related errors--survey of national university hospitals in Japan].

It is obvious that pharmacists play a critical role as risk managers in the healthcare system, especially in medication treatment. Hitherto, there is not a single multicenter-survey report describing the effectiveness of clinical pharmacists in preventing medical errors from occurring in the wards in Japan. Thus, we conducted a 1-month survey to elucidate the relationship between the number of errors and working hours of pharmacists in the ward, and verified whether the assignment of clinical pharmacists to the ward would prevent medical errors between October 1-31, 2009. Questionnaire items for the pharmacists at 42 national university hospitals and a medical institute included the total and the respective numbers of medication-related errors, beds and working hours of pharmacist in 2 internal medicine and 2 surgical departments in each hospital. Regardless of severity, errors were consecutively reported to the Medical Security and Safety Management Section in each hospital. The analysis of errors revealed that longer working hours of pharmacists in the ward resulted in less medication-related errors; this was especially significant in the internal medicine ward (where a variety of drugs were used) compared with the surgical ward. However, the nurse assignment mode (nurse/inpatients ratio: 1 : 7-10) did not influence the error frequency. The results of this survey strongly indicate that assignment of clinical pharmacists to the ward is critically essential in promoting medication safety and efficacy.