Dabigatran etexilate is a potent, selective and competitive inhibitor of thrombin. It is an oral prodrug of dabigatran. Ki=4.5 nM for human thrombin and IC50=10 nM for thrombin-induced platelet aggregation. [1] [2]
Thrombin is protein that proteolytically cleaved from coagulation factor II as the initial step in the coagulation cascade. It transforms fibrinogen into fibrin and activates other factors in function in blood homeostasis, wound healing and inflammation.
In vitro, dabigatran showed anticoagulant effects in a concentration-dependent manner. It doubled the activated partrial thromboplastin time, prothrombin time and ecarin clotting in human PPP. [1]
In rats and rhesus monkeys, activated partial throboplastin time was extended by dabigaran.
Rats orally administrated with dabigatran etexilate exerted anticoagulant effects in a dose and time –dependent manner. [1]
Compared with warfarin, dabigatran administered orally (150 mg dose) in patients with atrial fibraillation, exhibited lower rates of stroke and systemic embolism but similar rates of major hemorrhage. [2]
References:
1. Wienen W, Stassen JM, Priepke H et al. In-vitro profile and ex-vivo anticoagulant activity of the direct thrombin inhibitor dabigatran and its orally active prodrug, dabigatran etexilate. Thromb Haemost. 2007 Jul;98(1):155-62.
2. Connolly SJ, Ezekowitz MD, Yusuf S et al. Dabigatran versus warfarin in patients with atrial
fibrillation. N Engl J Med. 2009 Sep 17;361(12):1139-51.