Impact of drug–drug interactions in hospitalised COVID-19 patients: association with polytherapy, comorbidities, and disease severity

Introduction : Drug–drug interactions (DDIs) influence treatment outcomes, particularly in complex diseases such as coronavirus disease 2019 (COVID-19). This study aimed to evaluate the impact of DDIs in COVID-19 patients. Materials and methods : A study was conducted on 200 patients with mild, moderate, or severe COVID-19 infections. Next, DDIs were classified into five risk categories (A–X). Results : Altogether, 1689 DDIs were identified (maximum of 64 per patient). Most interactions were category C (65.3%). Clinically significant DDIs (C–X) accounted for 73.6% of interactions. Positive correlations were found between the total number of DDIs and both the total number of drugs (very strong) and comorbidities/diagnoses (strong). Patients with severe COVID-19 infections had significantly more DDIs and drugs used. Polypharmacy was highly frequent (97.5%, average of 9.9 drugs per patient). Conclusion : Overall, COVID-19 patients often have clinically significant DDIs resulting from polypharmacy and comorbidities, especially in severe cases. Systematic DDI assessment is essential.