Ximelagatran is an orally administered direct thrombin inhibitor under development as an anticoagulant agent for prophylaxis against and treatment of thromboembolism. Ximelagatran is rapidly absorbed and quickly converted into its active form Melagatran, a reversible, active-site inhibitor of both free and clot-bound thrombin that has stable and reproducible pharmacokinetic properties. Initial studies have shown Ximelagatran to have good efficacy and safety in the prevention of venous thromboembolism after total knee or total hip replacement.