Drug-Drug Interactions in Polypharmacy: A Retrospective Hospital Study
DOI:
https://doi.org/10.70749/ijbr.v4i3.3030Keywords:
Drug–drug Interactions, Polypharmacy, Adverse Drug Events, Pharmacokinetics, Comorbidities, Medication Safety.Abstract
Background: Polypharmacy is increasingly common in clinical practice and is associated with a higher risk of drug–drug interactions (DDIs), which can lead to adverse drug events, reduced therapeutic efficacy, and increased healthcare burden. Objective: To determine the prevalence, patterns, and predictors of drug–drug interactions among patients with polypharmacy. Methods: This retrospective observational study was conducted at Shalamar Hospital, Lahore from September 2025 to January, 2026 , and included 180 adult patients receiving five or more medications. Data were collected from medical records, prescription charts, and electronic databases. Drug–drug interactions were identified using standard interaction databases and classified based on severity and mechanism. Results: The mean age of patients was 54.6 ± 15.2 years, with 56.7% males. The average number of medications per patient was 7.8 ± 2.1. Drug–drug interactions were identified in 78.9% of patients, with a mean of 2.9 ± 1.6 interactions per patient. Moderate interactions were most common (42.2%), followed by major (21.1%) and minor (15.6%) interactions. Pharmacokinetic interactions accounted for 60.6% of cases. A significant association was observed between DDIs and number of medications (p < 0.001), age ≥60 years (p = 0.02), and presence of ≥3 comorbidities (p = 0.01). Conclusion: Drug–drug interactions are highly prevalent among patients with polypharmacy, with medication burden and comorbidities being the strongest predictors.
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