Fondaparinux for post-operative venous thrombosis prophylaxis.

Fondaparinux (Arixtra TM ) belongs to a new class of synthetic antithrombotic agents called pentasaccharides. It was recently approved in Canada for the prevention of venous thromboembolic events (VTE) in patients undergoing orthopedic surgeries of the lower limbs such as hip fracture, knee surgery and hip replacement surgery. Fondaparinux was more efficacious in three of four phase III trials comparing fondaparinux and enoxaparin for the prevention of deep vein thrombosis (DVT) and/or pulmonary embolism (PE) in patients undergoing major orthopedic surgery. However, there was no difference in the incidence of pulmonary embolism (PE) between the two treatment groups in any of the four trials. The overall major bleeding rate associated with fondaparinux was higher than the rate associated with enoxaparin, although the statistical significance of this difference is inconsistent.