Novel Drug-Drug Interaction of Potential Rifabutin-Induced Edoxaban Failure: A Case Report.

Purpose: To report an incident of a breakthrough deep vein thrombosis (DVT) and potential example of a drug-drug interaction in a patient treated with edoxaban and rifabutin who was being treated for respiratory tuberculosis. Case: A 76-year-old male presented with anemia requiring transfusion and subsequent shortness of breath that was later diagnosed to be respiratory tuberculosis. He experienced a prolonged hospital stay due to persistently positive Mycobacterium tuberculosis respiratory samples and a complicated social situation that required continuous hospitalization for approximately five months. During his treatment the patient was transitioned from apixaban to edoxaban due to a drug-drug interaction with rifabutin. He subsequently had a DVT while on edoxaban after two months of therapy that would require him to transition to warfarin. Conclusion: This case represents an example of a potentially significant drug-drug interaction between edoxaban and rifabutin. Other direct oral anticoagulants (DOACs) exhibit a potential drug-drug interaction that limit their effectiveness when used with rifamycins. This report describes the first known case of a patient experiencing a DVT after prolonged edoxaban use in combination with rifabutin. Treatment with DOACs for patients taking concomitant cytochrome P450 (CYP) inducers such as rifabutin may be more complicated than previously believed.