Tecarfarin

Tecarfarin 

Tecarfarin is a vitamin K analogue which acts by inhibiting vitamin K epoxide reductase. Tecarfarin is highly bound to plasma proteins and has a half life of nearly five days (119 hours). It is not metabolized by cytochrome P450 enzyme system. Instead, the metabolism is by hepatic microsomal carboxylesterases. Hence it has less potential for drug interactions, unlike warfarin. Another advantage is the availability of INR (international normalized ratio of prothrombin time) monitoring with a well established therapeutic range. Moreover, unlike other newer antithrombotic agents which do not have antidotes, the action of tecarfarin is reversible by the administration of vitamin K.

EmbraceAC trial compared tecarfarin with warfarin in a randomized double blind trial of those requiring long term anticoagulation: with atrial fibrillation, prosthetic heart valve, venous thromboembolism or a history of myocardial infarction or cardiomyopathy. The primary outcome was control of INR in the form of time in therapeutic range. Six hundred odd patients were enrolled and treated for six months. The time in therapeutic INR range was 74 percent for tecarfarin and 73.2 percent for warfarin (P = 0.506). Authors attribute the surprisingly high time in therapeutic range (TTR) for warfarin in this trial to be due to the skill of physicians at the dose control center. In those having mechanical prosthetic valves also the TTR was comparable to that of warfarin [1].

Reference

1. Richard P Whitlock, Christopher B Fordyce, Mark G Midei, Dave Ellis, David Garcia, Jeffrey I Weitz, Daniel M Canafax, Detlef Albrecht, Peter G Milner. A randomised, double blind comparison of tecarfarin, a novel vitamin K antagonist, with warfarin. The EmbraceAC Trial. Thromb Haemost. 2016 Aug 1;116(2):241-50.