Evaluation of Drug Utilization Patterns and Potentially Inappropriate Prescribing among Patients Attending a Tertiary Care Centre: A Retrospective Observational Study

Abstract

Background: Rational use of medicines is an essential component of safe and effective healthcare. Inappropriate prescribing, polypharmacy, excessive use of selected therapeutic classes and inadequate use of generic medicines may increase the risk of adverse drug reactions, drug interactions, medication errors and unnecessary healthcare expenditure. Drug utilization studies provide useful information regarding prevailing prescribing practices and help identify opportunities for improving the quality of pharmacotherapy. The present study was undertaken to evaluate drug utilization patterns and the prevalence of potentially inappropriate prescribing among patients attending a tertiary care centre. Methods: A retrospective observational study was conducted using 400 patient records from selected clinical departments of a tertiary care centre over a 12-month period from July 2023 to June 2024. Demographic characteristics, clinical department, primary diagnosis, number of comorbidities, number of prescribed medicines, generic prescribing, antibiotic use, proton pump inhibitor (PPI) use, non-steroidal anti-inflammatory drug (NSAID) use, fixed-dose combinations (FDCs), and potentially inappropriate prescribing (PIP) were assessed. Polypharmacy was defined as prescription of five or more medicines during the assessed clinical encounter. Descriptive statistics were used to summarize prescribing patterns. Results: Among the 400 patient records analysed, 208 (52.0%) were from males and 192 (48.0%) from females. The mean age was 51.95±17.12 years (range, 18–90 years). General Medicine accounted for the largest proportion of records (33.5%), followed by General Surgery (18.0%) and Obstetrics and Gynaecology (14.8%). The median number of medicines prescribed per patient was four, while 148 (37.0%) received five or more medicines. Antibiotics were prescribed in 192 (48.0%) records, PPIs in 235 (58.8%), NSAIDs in 118 (29.5%), and FDCs in 115 (28.8%) records. The mean recorded generic-prescribing percentage was 56.21±17.47%. PIP was identified in 48 (12.0%) records (95% CI, 9.2%–15.6%). Patients with PIP received a greater mean number of medicines than those without PIP (5.04±1.56 vs. 3.78±1.42). Polypharmacy was significantly associated with PIP (χ²=25.16, p<0.001, Pearson chi-square with continuity correction). Among patients aged ≥65 years, 48/91 (52.7%) had PIP, compared with 0/309 among those aged <65 years (χ²=180.25, p<0.001, Pearson chi-square with continuity correction). Conclusion: The study demonstrated substantial polypharmacy and frequent prescribing of selected therapeutic classes in routine clinical practice. PIP was identified in 12.0% of records and was concentrated among older patients and those receiving multiple medicines. These findings support systematic medication review, particularly for older adults and patients exposed to complex medication regimens. Interpretation of PIP, however, depends on the validated assessment criterion used and should be reported explicitly in the final submission.