1151. Evaluation of Prevalence of Potential Drug-Drug Interaction among Patients with Invasive Fungal Infections Receiving Mold-Active Triazoles
Session: Poster Abstract Session: Pharmacological Studies of Antifungals
Friday, October 9, 2015
Room: Poster Hall
Background: Fluconazole is used to manage invasive fungal infections; but, resistance has been increasing due to the rising prevalence of non-Candida species and lack of activity against opportunistic mold infections. Newer drugs including itraconazole, voriconazole, and posaconazole are mold-active triazoles (MAT) with broader activity; but, complex pharmacokinetics and interactions with concomitant drugs via various pathways can lead to adverse events. This study evaluated the prevalence of potential drug-drug interactions (PDDI) where 2 or more interacting drugs were used concomitantly. 

Methods: Cerner HealthFacts, an electronic medical record with over 110 million hospitalizations, was used for this analysis (2005-2013). The study population was hospitalized US adults with MAT use. The first MAT used during any hospitalization was defined as the index triazole and index hospitalization. PDDIs were categorized using drug labels and DRUGDEX, an evidence-based system that classified interactions into 4 groups (contraindicated; major; moderate; minor). Minor PDDIs were not counted. A random hospitalization was chosen if a patient had multiple eligible hospitalizations. A PDDI event was considered to have occurred if both conditions were met: 1) used at least one drug with at least a moderate interaction classification with the index triazole during the index hospitalization and 2) there was at least a 1-day administration overlap between the index triazole and the given drug.

Results: 6962 hospitalizations were identified with MAT use, of which 6101 (87.6%) had evidence of a PDDI. 88% of voriconazole (n=4751), 86% of itraconazole (n=1784), and 93% of posaconazole (n=417) users had a PDDI. 26% of all hospitalizations with MAT use had at least 1 contraindicated PDDI, the most severe PDDI classification. 68% of hospitalizations with posaconazole, 34% of itraconazole, and 20% of voriconazole had at least 1 contraindicated PDDI. The most common drug interaction among all 3 MATs was with ondansetron. 

Conclusion: Although this study could not directly assess the proportion of PDDIs that actually led to clinical events, the findings suggest that a majority of hospitalized patients receiving MATs were at risk for severe drug-drug interactions based on the concomitant medications assessed.

David Andes, MD, FIDSA1, Nkechi Azie, MD2, Hongbo Yang, PhD3, Caroline Kelley, BA3, Ruo-Ding Tan, Ph.D.3, Yichen Zhong, MHS3, Billy Franks, PhD4, Rita Kristy, MS2, Edward Lee, PharmD2, Nikhil Khandelwal, PhD2 and James Spalding, PharmD2, (1)University of Wisconsin, Madison, WI, (2)Astellas Pharma Global Development, Inc., Northbrook, IL, (3)Analysis Group, Boston, MA, (4)Astellas Pharma Europe B.V., Northbrook, IL


D. Andes, None

N. Azie, None

H. Yang, None

C. Kelley, None

R. D. Tan, None

Y. Zhong, None

B. Franks, Astellas: Employee , Salary

R. Kristy, None

E. Lee, Astellas: Employee , Salary

N. Khandelwal, None

J. Spalding, Astellas: Employee , Salary

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