Critical
Apixaban × Rifampicin
Direct oral anticoagulants (factor Xa inhibitors)×Antituberculous antibiotic
Mechanism
Rifampicin is the strongest clinical inducer of CYP3A4 and P-glycoprotein. Apixaban levels fall by 54%, anticoagulation lost. FDA recommends avoiding the combination.
Symptoms
Ischemic stroke or recurrent VTE on apparently active apixaban. Lab: low anti-Xa level.
Management
Combination contraindicated. For tuberculosis treatment in an atrial fibrillation patient, use warfarin with target INR 2.5–3.5 and more frequent monitoring (rifampicin also induces CYP2C9 and weakens warfarin – higher doses needed).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.