Heparin and low molecular weight heparins have limitations in their efficacy and 
safety for the prevention and treatment of venous thromboembolism (VTE). New 
synthetic antithrombotic drugs, designed with the intention of improving the 
therapeutic window for prophylaxis and treatment, are in various stages of 
development. Synthetic pentasaccharides include fondaparinux and its long-acting 
analogue idraparinux. Dabigatran is a direct thrombin inhibitor that has 
undergone clinical trials for VTE prophylaxis and treatment. Direct factor Xa 
inhibitors include rivaroxiban, which has shown promising results for VTE 
prophylaxis and is being studied for VTE treatment, as well as apixaban and 
betrixaban, which are at earlier stages of clinical validation. These newer 
agents may represent viable options for prophylaxis and therapy as further 
clinical studies are performed.