Novel oral anticoagulants – NOACs

Novel oral anticoagulants – NOACs

Novel oral anticoagulants – NOACs: Warfarin is the standard oral anticoagulant in use for a long time. But there are a quite a few disadvantages for warfarin in spite of its reasonable efficacy. Most important is the unpredictable biological action needing frequent monitoring of anticoagulant efficacy with prothrombin time international normalized ratio (PT-INR) monitoring. This often means travel to a distant laboratory and hospital for individuals staying far from a tertiary care centre. Innumerable drug – drug and food – drug interactions of warfarin makes it quite difficult even for an experienced physician to the monitor warfarin on long term without bleeding or clotting complications. Hence the role of the novel oral anticoagulants or NOACs.

Currently available NOACs are the direct thrombin inhibitor dabigatran and factor Xa inhibitors rivaroxaban and apixaban. Dabigatran has been used fairly widely for thromboprophylaxis in atrial fibrillation with risk factors for stroke. Apixaban has been used well in thromboprophylaxis following orthopedic surgery. They are also being used increasingly for other indications as well.

An important disadvantage of NOACs is the high cost and low availability antidotes in case of bleeding due to overdosage. Idarucizumab is a monoclonal antibody used for dabigatran reversal. Andexanet Alfa is the antidote for factor Xa inhibitors. But in general, NOACs have a lower risk of intracranial bleeding than warfarin. They have not yet been approved for use in those with prosthetic heart valves. As of date warfarin is still the recommendation of choice in those with prosthetic heart valves.