Critical
Apixaban × Carbamazepine
Direct oral anticoagulants (factor Xa inhibitors)×Antiepileptics. Carboxamide derivatives
Mechanism
Carbamazepine is a strong CYP3A4 and P-glycoprotein inducer. Apixaban plasma concentration falls by 50–75%, eliminating stroke protection in atrial fibrillation and VTE recurrence protection. FDA recommends avoiding the combination.
Symptoms
No overdose symptoms – the danger is undertreatment: ischemic stroke, recurrent DVT or PE despite ongoing anticoagulant.
Management
Combination contraindicated. Alternative anticoagulant when carbamazepine is needed: warfarin (effect tracked by INR, induction can be compensated). Alternative anticonvulsant: levetiracetam or lacosamide, neither induces CYP3A4.
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.