TY - JOUR
T1 - Evaluation of Warfarin Drug Interaction Listings in US Product Information for Warfarin and Interacting Drugs
AU - Hines, Lisa E.
AU - Ceron-Cabrera, Diana
AU - Romero, Klaus
AU - Anthony, Marietta
AU - Woosley, Raymond L.
AU - Armstrong, Edward P.
AU - Malone, Daniel C.
PY - 2011/1
Y1 - 2011/1
N2 - Background: Because interactions with warfarin represent a serious risk to patients, drug information sources used by clinicians should contain accurate, timely, and practical drug interaction information. Objective: The aim of this study was to assess the information regarding warfarin interactions that is included in the official labeling of prescription products that interact with warfarin. Methods: We examined the official labeling information approved by the US Food and Drug Administration for the 50 drugs, biologics, and drug classes that were commonly identified by 3 drug information compendia-Clinical Pharmacology, ePocrates®, and Micromedex®-and the warfarin US prescribing information (PI) as having an interaction with warfarin. The PI of each product was assessed for possible mention of an interaction with warfarin. The data were collected and tabulated by 1 investigator. A clinical investigator evaluated the data for accuracy and consistency. Unresolved issues were discussed with a third investigator and decided by consensus. The interaction listings were compared to determine similarities, differences, and inconsistencies and analyzed by 5 investigators. Results: Of the labeling for 73 products evaluated, 62 (85%) included mention of an interaction with warfarin. Those failing to mention the warfarin interaction were for older generic drugs or influenza vaccine. Among the labels listing an interaction with warfarin, the location of the information, the terminology used, and the inclusion of evidence for the interaction was inconsistent When considering the PI for all 73 products, Fleiss' kappa coefficient (κ = 0.467) suggested moderate concordance according to the method of Landis and Koch. Conclusion: This assessment of official US product labeling for 50 drugs, biologics, and drug classes known to interact with warfarin, comprising 73 distinct agents, found that 15% failed to mention the interaction, even though the interaction was mentioned in the warfarin labeling.
AB - Background: Because interactions with warfarin represent a serious risk to patients, drug information sources used by clinicians should contain accurate, timely, and practical drug interaction information. Objective: The aim of this study was to assess the information regarding warfarin interactions that is included in the official labeling of prescription products that interact with warfarin. Methods: We examined the official labeling information approved by the US Food and Drug Administration for the 50 drugs, biologics, and drug classes that were commonly identified by 3 drug information compendia-Clinical Pharmacology, ePocrates®, and Micromedex®-and the warfarin US prescribing information (PI) as having an interaction with warfarin. The PI of each product was assessed for possible mention of an interaction with warfarin. The data were collected and tabulated by 1 investigator. A clinical investigator evaluated the data for accuracy and consistency. Unresolved issues were discussed with a third investigator and decided by consensus. The interaction listings were compared to determine similarities, differences, and inconsistencies and analyzed by 5 investigators. Results: Of the labeling for 73 products evaluated, 62 (85%) included mention of an interaction with warfarin. Those failing to mention the warfarin interaction were for older generic drugs or influenza vaccine. Among the labels listing an interaction with warfarin, the location of the information, the terminology used, and the inclusion of evidence for the interaction was inconsistent When considering the PI for all 73 products, Fleiss' kappa coefficient (κ = 0.467) suggested moderate concordance according to the method of Landis and Koch. Conclusion: This assessment of official US product labeling for 50 drugs, biologics, and drug classes known to interact with warfarin, comprising 73 distinct agents, found that 15% failed to mention the interaction, even though the interaction was mentioned in the warfarin labeling.
KW - Adverse drug event
KW - Drug interaction
KW - Food and Drug Administration
KW - Product labeling
KW - Warfarin
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U2 - 10.1016/j.clinthera.2011.01.021
DO - 10.1016/j.clinthera.2011.01.021
M3 - Article
C2 - 21397772
AN - SCOPUS:79952495577
SN - 0149-2918
VL - 33
SP - 36
EP - 45
JO - Clinical Therapeutics
JF - Clinical Therapeutics
IS - 1
ER -