Dabigatran (Pradaxa ®) is a new oral anticoagulant. It is used to prevent venous thromboembolism in orthopedic surgery and has recently demonstrated efficacy and safety at least as good as anticoagulants in the prevention of thromboembolism in atrial fibrillation and the treatment of venous thromboembolism. It is administered with fixed dose and does not require laboratory monitoring because of the low inter and intra individual pharmacokinetic (PK) and pharmacodynamics (PD) of dabigatran. However, the bioavailability of dabigatran is very low (6.5%) and is controlled by an efflux protein, P-GP. This molecule has a genetic polymorphism. The inhibition of this protein can cause a significant increase in intestinal absorption of dabigatran and expose patients to a risk of bleeding by overdose. Two major drug interactions have been identified : quinidine (cons-indication) and amiodarone (precautions). It is likely that other interactions exist and can be clinically significant in patients not selected such as testing. The development of tools to study the influence of P-GP on the PK and PD of dabigatran is therefore interesting. As the P-GP has a genetic polymorphism, the study of the latter is an important element in the detection of drug interactions. In this sense, clarithromycin, a potent inhibitor of P-GP is a good model to evaluate the primary mechanism of drug interaction of dabigatran and optimize the experimental design of studies to be conducted.