Assessment of the potential impact of resolving drug-related problems by clinical pharmacists in Japan: a retrospective observational study.

Background: Clinical pharmacists play a role in limiting the disadvantages of pharmacotherapy for patients by detecting and resolving drug-related problems (DRPs) through medication reviews. Although their contributions to patient care have been analyzed and understood in various countries, the role of Japanese clinical pharmacists in this context remains to be clearly elucidated. Thus, in this study, we aimed to elucidate the detection of DRPs by clinical pharmacists and determine the potential impact of pharmacist interventions in Japan.

Methods: This study was conducted in a 273-bed hospital and targeted hospitalized patients over a period of 6 months. DRPs detected by clinical pharmacists during the study period were investigated and classified into 10 types. Furthermore, medications were categorized according to the Anatomical Therapeutic Chemical classification. A review committee consisting of two pharmacists independently reviewed the pharmacist interventions on a six-point scale (extremely significant, very significant, significant, somewhat significant, no significance, adverse significance) according to the potential impact on patient care.

Results: During the study period, 1711 patients (mean age: 71.2 years, 54.1% male) were included, and 2149 DRPs were detected (1.26 DRPs/patient). Pharmacists intervened in all the DRPs detected. The most common DRP was supratherapeutic dosage (19.3%), followed by untreated indication (18.1%). The most common medication classification causing DRPs was "Antiinfectives for Systemic Use" (25.1%), followed by "Alimentary Tract and Metabolism" (19.9%). Most of the pharmacist interventions (99.6%) were rated "somewhat significant" or more significant, of which 1.1% were rated "extremely significant," and none were rated as "adverse significance."

Conclusions: Our results show that in Japan, as in other countries, clinical pharmacists detect and resolve DRPs in hospitalized patients through medication review. Our findings also show that clinical pharmacists have a positive impact on patient care and suggest the need for their involvement.