Pros and cons of new oral anticoagulants.

The availability of new oral anticoagulants (NOACs) targeting either thrombin (dabigatran etexilate) or factor Xa (rivaroxaban and apixaban) for the prevention and treatment of thrombosis has been highly anticipated. NOACs have major pharmacologic advantages over vitamin K antagonists (eg, warfarin), including rapid onset/offset of action, few drug interactions, and predictable pharmacokinetics, eliminating the requirement for regular coagulation monitoring. Regulatory agencies have approved several NOACs for specific indications based on the results of clinical trials demonstrating efficacy and safety that are at least as good, if not better, than warfarin (for stroke prevention in atrial fibrillation and treatment and secondary prevention of venous thromboembolism) or low-molecular-weight heparin, which is injectable (for initial treatment of venous thromboembolism and thromboprophylaxis in patients undergoing hip or knee arthroplasty). However, the adoption of this new therapeutic class into clinical practice has been slower than expected due to several factors including concerns regarding medication adherence without laboratory monitoring, uncertainty about dosing in some patient populations (eg, renal dysfunction, marked extremes of body weight), and higher drug costs compared with warfarin. Other issues are the current absence of specific antidotes for NOACs and assays to measure drug levels at most centers. The indications for NOACs on the market will expand and at least one additional agent (edoxaban) will likely gain approval within the next 2 years. As practitioners gain familiarity with the drugs and healthcare systems adapt to their use, NOAC use will increase substantially over time. Warfarin, however, will continue to be an appropriate anticoagulant choice for many patients.