Major
Apixaban × Rifampicin
Direct oral anticoagulants (factor Xa inhibitors)×Antituberculous antibiotic
Mechanism
Rifampicin strongly induces CYP3A4 and P-glycoprotein – two apixaban clearance routes. Apixaban plasma levels fall by 50%; anticoagulant effect weakens.
Symptoms
The patient feels nothing. Thromboembolic risk rises: stroke in atrial fibrillation, deep vein thrombosis, pulmonary embolism.
Management
The combination is not prescribed. Alternative anticoagulants: warfarin with INR monitoring or low molecular weight heparin for short courses. Induction persists for 2 weeks after rifampicin stops.