Real world co‐prescribing contraindicated drugs with fluconazole and itraconazole

Abstract

AbstractPurposeThis study aimed to investigate co‐prescribing of contraindicated drugs with fluconazole and itraconazole using real‐world nationwide data.MethodsThis retrospective cross‐sectional study was performed using claims data collected by the Health Insurance Review and Assessment Service (HIRA) of Korea during 2019–2020. To determine the drugs that should be avoided in patients taking fluconazole or itraconazole, Lexicomp® and Micromedex® were used. The co‐prescribed medications, co‐prescription rates, and potential clinical consequences of the contraindicated drug–drug interactions (DDIs) were investigated.ResultsOf the 197 118 prescriptions of fluconazole, 2847 co‐prescriptions with drugs classified as contraindicated DDI by either Micromedex® or Lexicomp® were identified. Further, of the 74 618 prescriptions of itraconazole, 984 co‐prescriptions with contraindicated DDI were identified. Solifenacin (34.9%), clarithromycin (18.1%), alfuzosin (15.1%), and donepezil (10.4%) were frequently found in the co‐prescriptions of fluconazole, whereas tamsulosin (40.4%), solifenacin (21.3%), rupatadine (17.8%), and fluconazole (8.8%) were frequently found in the co‐prescriptions of itraconazole. In 1105 and 95 co‐prescriptions of fluconazole and itraconazole, accounting for 31.3% of all co‐prescriptions, potential DDIs were associated with a risk of corrected QT interval (QTc) prolongation. Of the total 3831 co‐prescriptions, 2959 (77.2%) and 785 (20.5%) were classified as contraindicated DDI by Micromedex® alone and by Lexicomp® alone, respectively, whereas 87 (2.3%) were classified as contraindicated DDI by both Micromedex® and Lexicomp®.ConclusionsMany co‐prescriptions were associated with the risk of DDI‐related QTc prolongation, warranting the attention of healthcare providers. Narrowing the discrepancy between databases that provide information on DDIs is required for optimized medicine usage and patient safety.