Predictors of potential clinically harmful drug–drug interactions at the medical wards in the University of Benin Teaching Hospital, Benin City

Drug-drug interactions are preventable causes of adverse events. Different factors have been recognized as important predictors of drug-drug interactions but few studies have addressed these predictors in patients admitted into medical wards of a tertiary hospital in Nigeria hence this study. This was a retrospective study conducted using case records of patients admitted into the medical wards between January 1 and December 31, 2020. Patients were selected using a systematic random sampling method. Socio-demographic details including age, gender, number of comorbidities, and number of medications prescribed and diagnosis were collected on days 1, 3, and at discharge. Potential drug-drug interactions were checked using Lexi-interact® software. Analysis was set at p < 0.05. A total of 430 case records were included in this study based on the inclusion criteria. Lexi-interact recorded a prevalence of (217) 50.5% on day 1, (146) 34.0% on day 3, and (290) 67.4% at discharge. A significant association (p < 0.05) was found between the potential drug-drug interactions (DDI) and an increased number of medicines prescribed on all the days of admission. Also, patients without certain infectious or parasitic diseases have reduced odds of developing DDI. There is a need for continuous monitoring of medications from admission to discharge especially in the elderly, those on multiple medications, certain infectious or parasitic diseases, and comorbidities as these impact on DDIs.