The new or non-vitamin K antagonist oral anticoagulants: what have we learned since their debut.

One of the major advances in the management of thrombosis is arguably the introduction of the new non-vitamin K antagonist oral anticoagulants (NOACs). These are small molecules, designed to directly inhibit specific steps in the coagulation pathway, with dabigatran (Pradaxa), inhibiting thrombin and rivaroxaban (Xarelto), apixiban (Eliquis), edoxaban (Lixiana), and betrixaban being factor Xa inhibitors. They have several advantages over vitamin K antagonists such as warfarin, with more predictable bioavailability, fewer drug interactions, and improved safety, especially intracranial hemorrhage. Yet, since their debut, several issues have arisen with their increasing usage, with concerns over monitoring and reversal, being predominant. Issues addressed in this article include their efficacy, bleeding risk, and the recognition of a vulnerable population where monitoring is needed. The current approach to reversing the drug action is updated. The change in the approach to future drug design is also discussed.