Anticoagulation is recommended for prophylaxis and treatment of venous 
thromboembolism (VTE) (deep vein thrombosis and pulmonary embolism) and/or 
arterial thromboembolism. The therapeutic arsenal of anticoagulants available to 
clinicians is mainly composed by unfractionated heparin (UFH), 
low-molecular-weight heparin (LMWH), fondaparinux and oral vitamin K antagonists 
(VKA) (i.e. warfarin and acenocumarol). These anticoagulants are effective, but 
they require parenteral administration (UFH, LMWH, fondaparinux) and/or frequent 
anticoagulant monitoring (intravenous UFH, oral VKA). Novel anticoagulants in 
clinical testing include orally active direct factor II inhibitors [dabigatran 
etexilate (BIBR 1048), AZD0837)], parenteral direct factor II inhibitors 
(flovagatran sodium), orally active direct factor X inhibitors [rivaroxaban (BAY 
59-7939), apixaban, betrixaban, YM150, DU-176b, LY-517717, GW813893, TAK-442, PD 
0348292] and new parenteral FXa inhibitors [idraparinux, idrabiotaparinux 
(biotinilated idraparinux; SSR 126517), ultra-low-molecular-weight heparins 
(ULMWH: AVE5026, RO-14)]. These new compounds have the potential to complement 
heparins and fondaparinux for short-term anticoagulation and/or to replace VKA 
for long-term anticoagulation in most patients. Dabigatran and rivaroxaban have 
been the firsts of the new oral anticoagulants to be licensed for the prevention 
of VTE after hip and knee replacement surgery. In the present review, we discuss 
the pharmacology of new anticoagulants, the key points necessary for 
interpreting the results of studies on VTE prophylaxis and treatment, the 
results of clinical trials testing these new compounds and their potential 
advantages and drawbacks over existing therapies.