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

Area of Science:

• Pharmacology
• Internal Medicine
• Infectious Diseases

Background:

• Respiratory tuberculosis (TB) management requires long-term treatment.
• Anticoagulation is crucial for preventing venous thromboembolism (VTE) in hospitalized patients.
• Drug-drug interactions (DDIs) can complicate treatment regimens, especially with multiple comorbidities.

Observation:

• A 76-year-old male with respiratory TB experienced a breakthrough deep vein thrombosis (DVT) while on edoxaban.
• The patient was previously transitioned from apixaban to edoxaban due to a suspected DDI with rifabutin, a potent inducer of cytochrome P450 (CYP) enzymes.
• The DVT occurred after two months of edoxaban therapy, necessitating a switch to warfarin.

Findings:

• This case illustrates a potential DDI between edoxaban and rifabutin, leading to reduced anticoagulant efficacy.
• Rifamycins, including rifabutin, are known to interact with direct oral anticoagulants (DOACs) by inducing CYP enzymes, potentially decreasing DOAC plasma concentrations.
• This is the first reported instance of DVT in a patient on prolonged edoxaban therapy concurrently with rifabutin.

Implications:

• The concurrent use of DOACs with strong CYP inducers like rifabutin may be more complex than anticipated.
• Clinicians should exercise caution when prescribing DOACs to patients receiving rifabutin or similar medications.
• Further research is warranted to elucidate the clinical significance and management strategies for DOAC-rifamycin interactions.