Assessing the effects of prescription adjustment and medication non-adherence associated with medication efficacy classifications from leftover drugs through the setsuyaku-bag campaign

The increase in medical expenditure has been worsening and poses a serious social problem. Commonly, leftover drugs are retained by patients. We estimated the possible reduction in prescription rates by appropriately reusing leftover drugs, and investigated the medication efficacy classifications that render leftover drugs due to the medication non-adherence. A retrospective cross-sectional survey of prescription data was performed at community pharmacies engaged in the appropriate reuse of leftover drugs through the SETSUYAKU-BAG campaign. We evaluated the drug costs and number of drugs originally prescribed, the reduction in expenditure and numbers after the use of leftover drugs, and then calculated the prescription reduction ratio (PRR) based on the number of drugs. Factors contributing to non-adherence were analyzed by the PRR. After reviewing the prescription information of 1792 patients, the reduction rate in drug expenditure was found to be 20.1％. Purgatives, Chinese medicines, and agents for peptic ulcer had higher PRRs and belonged to the top ten medications according to the prescription efficacy classifications. Non-adherence associated with the medication efficacy classifications was assessed by analyzing 5466 formulations. Thirty percent of formulations were found to be non-adherent. According to the medication efficacy classifications, six medications including agents for hyperlipidemias, peptic ulcer, psychotropics agents, and others, were less adherent than antihypertensives. These results suggest that adjusting prescriptions by appropriately reusing leftover drugs in community pharmacies could reduce medical costs. Further considerations are necessary for improving medication adherence in Japan. Healthcare providers should monitor medication adherence more carefully, with the results identified in this study.