COMPARATIVE ANALYSIS OF ONLINE DRUG–DRUG INTERACTION CHECKERS FOR ACCURACY, COMPLETENESS, AND CONSISTENCY
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Keywords
Drug–drug interactions, Lexidrug™, Medscape, Drugs.com, DrugBank, sensitivity
Abstract
Introduction: Drug–drug interactions (DDIs) are a major cause of preventable adverse drug reactions (ADRs), contributing to nearly one-quarter of ADR-related hospitalizations worldwide. With the increasing prevalence of polypharmacy, particularly among elderly and chronically ill patients, the risk of clinically significant DDIs has risen substantially. Subscription-based drug interaction databases such as Lexidrug™ are considered reliable because of their comprehensive, evidence-based information. However, in resource-limited settings, clinicians frequently rely on freely available online checkers like Medscape, Drugs.com, and DrugBank. Concerns remain regarding the accuracy, completeness, and consistency of these free tools.
Materials and methods: A cross-sectional study was conducted at the Institute of Pharmacology, Madras Medical College, Chennai, during August–September 2025. Using Stockley’s Drug Interactions (11th edition), 150 drug pairs (140 interacting, 10 non-interacting) involving at least one cardiovascular agent were evaluated. Each pair was entered into Medscape, Drugs.com, and DrugBank, and results were compared with Lexidrug™ as the reference standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Completeness was scored on a 4-point scale (mechanism, severity, management, references), and agreement in severity grading was analyzed using Cohen’s kappa.
Results: Drugs.com and DrugBank showed high sensitivity (>90%), while Medscape demonstrated lower sensitivity (~78%). Specificity was low across all platforms (≤40%), raising concerns about false positives and alert fatigue. Drugs.com provided the most comprehensive details, whereas DrugBank lacked clinical management advice. Agreement with Lexidrug™ severity grading was only fair (κ = 0.23–0.38).
Conclusion: Free DDI checkers offer accessible alternatives but show variable accuracy and completeness. Drugs.com performed best among free tools, though none matched the reliability of Lexidrug™. Regular validation and harmonization are needed to enhance their clinical utility.
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Dr. Kiranya Ravivarma
Postgraduate, Institute of Pharmacology, Madras Medical College & RGGGH, Chennai, Tamilnadu, India
Dr. A. Anandhalakshmi
Assistant Professor, Institute of Pharmacology, Madras Medical College & RGGGH, Chennai, Tamilnadu, India
Dr. K. M. Sudha
Professor, Institute of Pharmacology, Madras Medical College & RGGGH, Chennai, Tamilnadu, India