RESUMO
Objectives: Drug information systems are commonly used by professionals to assist in the identification of drug interactions and to ensure the safe use of medications. Real-world evidence about the comparison of different drug interaction sources is scarce. We aimed to compare two drug interaction databases to identify interactions in a population-based survey. Materials and Methods: This is a cross-sectional study based on a previous survey performed in the city of Manaus, Brazil, in 2019. We included adults aged 18 years and over, who used two or more medicines 15 days before the interview. To assess potential drug interactions, we searched Micromedex and UpToDate databases. The primary outcome was the prevalence of potential drug interactions in each database. Weighted Kappa statistics were calculated to assess agreement on the presence of drug interaction, documentation and severity. Results: A total of 752 participants were included in the study. The prevalence of drug interactions was 43.8% [95% confidence interval (CI): 40.2, 47.3%] in UpToDate and 30.2% (95% CI: 26.9, 33.5%), in Micromedex. The agreement related to drug interactions between the two databases was fair (Kappa: 0.631). For severity (Kappa: 0.398) and documentation (Kappa: 0.311), the agreement was poor. Conclusion: Agreement among compared databases was sub-optimal. Better quality and transparency of evidence available in drug interaction sources are needed to support informed healthcare professionals' decision.