Pharmacology, Pharmacokinetics, and Pharmacodynamics of Dabigatran Etexilate, an Oral Direct Thrombin Inhibitor

Dabigatran etexilate is a novel, oral reversible direct thrombin inhibitor that is rapidly absorbed and converted to its active form, dabigatran. Dabigatran has been shown to be a potent, competitive, and reversible inhibitor of thrombin, inhibiting both thrombin activity and generation. Studies in healthy volunteers and in patients undergoing orthopedic surgery indicate that dabigatran has a predictable pharmacokinetic profile, allowing for a fixed-dose regimen without the need for coagulation monitoring. In healthy volunteers, peak plasma concentrations of dabigatran are reached approximately 2 hours after oral administration. The elimination half-life is 12 to 14 hours, with clearance predominantly occurring via renal excretion of unchanged drug. Dabigatran is not metabolized by cytochrome P450 isoenzymes, has no interactions with food, and also has a low potential for drug-drug interactions. The pharmacokinetic profile of dabigatran is consistent across a broad range of different patient populations and is unaffected by gender, body weight, ethnic origin, obesity, and mild-to-moderate hepatic impairment. Small differences in dabigatran pharmacokinetics associated with age are attributable to variation in renal function. Dabigatran etexilate produces a predictable pharmacodynamic effect and requires no coagulation monitoring. It has been approved in the European Union (EU) and Canada for prophylaxis of thromboembolism in patients undergoing total knee or hip arthroplasty. Ongoing clinical trials are investigating its use in the treatment of venous thromboembolism, prevention of stroke in patients with nonvalvular atrial fibrillation, and treatment of thromboembolic complications, following acute coronary syndromes.