Unused Prescription Drugs in Hypertensive Patients: Magnitude and Causes

Abstract

Objective: To determine magnitude and causes of unused medications in hypertensive patients at a community hospital. Methods: The research employed mixed methodology with 2 phases of study. The first phase was a qualitative study to identify the causes of unused medications. The informants were 5 staff members of the hospital and 14 hypertensive patients. The researcher identify the causes of unused medications by in-depth interviewing with both groups of informants and organizing focus group discussion among patients. The second phase of the study was quantitative research to determine the magnitude of unused medications in hypertensive patients under treatment in the hospital for less than 2 years in order to reduce the probability of discarding unused or expired medications. The researcher counted the remaining pills during visits of homes of 81 patients and interviewed them to assess medication adherence. The obtained information and data on history of treatment in each patient were used to calculate the magnitude of unused medications according to various causes. Results:  The first phase of the study found that causes of unused medications included 1) medication noncompliance among the patients such as drug discontinuation due to adverse drug reactions, forgetting to take medication; 2) unintentional prescribing of drugs in a larger amount than the patient should receive including more than 10% oversupply of medications and redundant drug prescribing because of no review of past medication profiles; 3) lack of system for handling the cumulative unused medications from intentional drug prescribing including prescribing with amount of drug oversupply in case of drug loss and changes of drug treatments; and 4) receiving services from more than one health care settings such as referred patients and polypharmacy. The second phase of the study found that amount of unused medications was 110.62±88.29 tablets/patient/year with the cost of 70.75±57.51 bath/patient/year, accounting for 11.17% of total cost of prescribed medications. 53.74%, 24.92% and 8.27% of the cost of unused medications resulted from noncompliance, small intentional oversupply of medications, drug oversupply for more than 10%, respectively. There were 2,820 patients in the hospital's hypertensive clinic at the time of the research. The estimated value of unused medications was 199,515 baht per year. Conclusion: Information on the value of unused medications can help increase hospital staff's awareness of this issue. The causes and magnitude of unused medications from each cause allow for the development of intervention targeting at the major causes of the problem.