The interactions between anticonvulsants and non-vitamin K antagonist oral anticoagulant agents: A systematic review

Use of non-vitamin K antagonist oral anticoagulants (NOACs), including dabigatran etexilate, rivaroxaban, apixaban, edoxaban or betrixaban provides a safe and convenient alternative to the traditional anticoagulation with vitamin K antagonists or heparin derivatives. Many patients receiving long-term seizure prophylaxis with antiepileptic drugs (AEDs) may require anticoagulation with NOACs. Providers caring for these patients need to be informed about potential interactions between AEDs and NOACs and the relevant clinical consequences. A systematic review of the existing literature was conducted to elucidate current knowledge on the clinically relevant interactions between AEDs and NOACs and highlight areas in which further research is needed. The systematic review protocol was developed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance. Ovid MEDLINE, Embase, The Cochrane Library and SciFinder were searched. Of the 630 non-duplicate items identified by the search, 13 met eligibility criteria. These 13 items included 8 case reports, 2 letters to the editor and 3 nonrandomized studies. The majority of pharmacokinetic interactions between NOACs and first generation AEDs occurred via the induction of the hepatic enzyme system and competition for the P-glycoprotein transporter and lead to decreased NOAC plasma levels and consequent thrombotic events. Only one article, a case report, was identified that focused on interactions between the second generation AED and a NOAC. At the present time, the limited evidence suggests that enzyme-inducing or inhibiting AEDs reduce the effectiveness of anticoagulation produced by several NOACs. This information may help providers anticipate possible interactions and guide therapy appropriately.