Drug Interactions with Rifampin in a Tertiary Hospital: A Real-world Cross-sectional Study

Introduction: Rifampin interacts with a large number of medications, primarily by inducing several enzymes and transporters. The objective of this study was to describe the prevalence of drug-drug interactions (DDIs) with rifampin in an inpatient setting. Materials and Methods: We conducted a real-world cross-sectional study at an academic tertiary care hospital. Hospitalized adults who were receiving rifampin between 2017 and 2022 were included in the study. The primary study outcome was the prevalence of DDIs with rifampin, and the secondary outcomes were the DDI duration and severity. Results: A total of 465 patients were included in this study. A total of 336 (72.3%) patients and 42 medications had DDIs with rifampin. The total median (interquartile range) duration of DDI was 15 (5–40) days. The most common DDI was with omeprazole ( n = 176), dexamethasone ( n = 83), fentanyl ( n = 63), prednisolone ( n = 55), tramadol ( n = 52), midazolam ( n = 48), atorvastatin ( n = 44), amlodipine ( n = 41), doxycycline ( n = 40), and morphine ( n = 34). Conclusion: The prevalence of DDIs with rifampin among hospitalized patients was high. Awareness should be enhanced about these DDIs, and more studies are needed to identify the most common DDIs in different settings.