Fast Five Quiz: Direct Oral Anticoagulant Therapy for Atrial Fibrillation

Sandeep K. Goyal, MD


April 02, 2020

Figure 1. The physiological cascade of blood clotting.

Three of the four DOAC agents approved as anticoagulation therapy for patients with AF work through direct FXa inhibition (rivaroxaban, apixaban, edoxaban) or direct thrombin inhibition (dabigatran).

The other listed mechanisms refer to non-DOAC medication classes. Vitamin K antagonists (VKAs) include warfarin. Although a DOAC agent may directly inhibit thrombin, other agents work to indirectly inhibit thrombin. Heparin works to first activate antithrombin III, which then inhibits thrombin and FXa, among other enzymes. Experimental agents work to lyse or deplete fibrinogen; however, no such agents are currently approved for use in stroke prevention in patients with AF.

Learn more about the mechanism of action of DOAC agents.


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