Lack of drug interaction conformity in commonly used drug compendia for selected at-risk dermatologic drugs

Background: Systemic treatments that have significant efficacy for dermatologic conditions can often cause severe adverse reactions when improperly combined with interacting drugs. We have noted discrepancies in the reporting of such drug-drug interactions among major drug compendia used in hospitals and physicians' offices. Objective: The aim of this study was to compare the consistency of drug-drug interaction listings among four Of the most widely used English language drug compendia in the US. Methods: Drug monographs from Mosby's GenRx, USP DI, AHFS Drug Information, and the Physicians' Desk Reference were compared. The respective drug-drug interactions provided by the various compendia for four systemic agents - dapsone, erythromycin, methotrexate and prednisone - commonly prescribed for dermatologic purposes were compiled. Results: We found considerable discrepancies among the compendia with respect to the number of drug interactions listed. Agreement among the compendia was especially poor when more than two sources were compared. Conclusions: There is a need for a drug compendium that reconciles drug-drug interaction reporting discrepancies under standardized criteria based on the scientific literature and clinical significance.