Background: Preventing drug interactions is an important goal to maximize patient benefit from medications. Summarizing potential drug-drug interactions (PDDIs) for clinical decision support is challenging and there is no single repository for PDDI evidence. Additionally, inconsistencies across compendia and other sources have been well-documented. Standard search strategies for complete and current evidence about PDDIs have not heretofore been developed or validated. Objective: The purpose of this study was to identify common methods for conducting PDDI literature searches used by experts who routinely evaluate such evidence. Methods: A convenience sample of 70 drug information experts, including compendia editors, knowledge base vendors, and clinicians were invited via email to complete a survey on identifying PDDI evidence. An online survey was created and included questions addressing: 1) development and conduct of searches; 2) resources used e.g., databases, compendia, search engines etc.; 3) types of keywords used to search for specific PDDI information; 4) study types included and excluded in searches; and 5) search terms used. Search strategy questions focused on six topics of PDDI information: 1) that a PDDI exists; 2) seriousness; 3) clinical consequences; 4) management options; 5) mechanism; and 6) health outcomes. Results: Twenty participants (response rate 29%) completed the survey. The majority (85%) were drug information specialists, drug interaction researchers, compendia editors, or clinical pharmacists with 60% having over ten years' experience. Over half (55%) worked for clinical solutions vendors or knowledge-base vendors. Most participants develop (90%) and conduct (95%) search strategies without librarian assistance. PubMed (100%) and Google Scholar (55%) are most commonly searched for articles, followed by Google Web Search (35%) and EMBASE (15%). No respondents reported using Scopus. A variety of subscription and open-access databases were used, most commonly Lexicomp (9/20; 45%), Micromedex (8/20; 40%), Drugs@FDA (17/20; 85%), and DailyMed (13/20; 65%). Facts and Comparisons was the most commonly used compendia (8/20; 40%). Across the 6 attributes of interest, generic drug name was the most common keyword used. Respondents reported using more types of keywords when searching to identify existence of PDDIs and determine their mechanism than for the other four attributes (seriousness, consequences, management, and health outcomes). With respect to types of evidence useful for evaluating a PDDI, clinical trials, case reports, and systematic reviews were considered relevant, while animal and in vitro data studies were not.
Conclusions:The results suggest that drug information experts use various keyword strategies and various database and web resources depending on the PDDI evidence they are seeking to identify.