Background: Increasing polypharmacy and complicated prescription regimens raise the likelihood of CYP-mediated drug-drug
interactions (DDIs) in older people. Objective: To assess the incidence of CYP-mediated DDIs in older people with polypharmacy and
examine the correlation between medication dispensation and the likelihood of these interactions in this high-risk group. Methods: A
cross-sectional 17-week analysis was performed, including consecutive new patients aged 65 years and over who were undergoing
polypharmacy (defined as the use of more than five medications) at a community pharmacy. The medication profiles of these individuals
were evaluated using SuperCYPsPred software and UpToDate® Lexidrug. The frequency of possible CYP-mediated interactions was
evaluated. The pharmacists' judgments to suggest prescription adjustments based on the likelihood of CYP-mediated interactions were
documented. Results: The prevalence of possible CYP-mediated drug-drug interactions identified among 220 older persons with
polypharmacy was 84.5%. Moderate severity DDIs were the predominant and significant kind of interaction (2.70±3.157). A linear
regression analysis was performed to predict the frequency of drug interactions based on the number of drugs. A significant association
has been identified (F(1,14)= 67.789, p<0.001). The predominant CYP isoenzyme was CYP3A4 at 34.6%, followed by CYP2C9 at
21.4% and CYP2D6 at 15.7%, with no notable gender differences. Conclusion: The older patients have at least one DDI. Elderly adults
taking five or more medicines require frequent care owing to a fourfold greater chance of drug interactions.