Apixaban is an orally active inhibitor of coagulation factor Xa with anticoagulant activity. Apixaban directly inhibits factor Xa, thereby interfering with the conversion of prothrombin to thrombin and preventing formation of cross-linked fibrin clots. Apixaban has been available in Europe since May 2012. An FDA decision on apixaban which was expected on June 28, 2012 was initially delayed before final approval on December 28, 2012. On August 21, 2014, Pfizer announced that apixaban was now FDA approved for treatment and secondary prophylaxis of deep vein thrombosis (DVT) and pulmonary embolism (PE). It is being developed in a joint venture by Pfizer and Bristol-Myers Squibb. It has also been used to lower the risk of developing venous thrombosis post-orthopedic surgical procedures.

Rivaroxaban (trade name Xarelto) is an oral anticoagulant. It is the first available orally active direct factor Xa inhibitor. Upon oral administration, rivaroxaban selectively binds to both free factor Xa and factor Xa bound in the prothrombinase complex. This interferes with the conversion of prothrombin (factor II) to thrombin and eventually prevents the formation of cross-linked fibrin clots. Rivaroxaban does not affect existing thrombin levels. Activation of factor X to factor Xa (FXa) via the intrinsic and extrinsic pathways plays a central role in the cascade of blood coagulation. Xarelto is indicated to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, treatment and prophylaxis of deep vein thrombosis (DVT) which may lead to PE in patients undergoing knee or hip replacement surgery, pulmonary embolism (PE) and for the reduction in the risk of recurrence of deep vein thrombosis and of pulmonary embolism following initial 6 months treatment for DVT and/or PE.

Desirudin (Iprivask), a recombinant hirudin, is a parenteral direct thrombin inhibitor approved to prevent venous thromboembolism in patients undergoing elective hip replacement surgery. Desirudin is a potent inhibitor of both clot-bound and freely circulating thrombin. Desirudin acts independently of anti-thrombin, forming a noncovalent irreversible complex with both the active site of thrombin as well as the fibrinogen binding site. This Desirudin–thrombin complex prevents fibrinogen cleavage and other thrombin catalyzed reactions such as the activation of clotting factors V, VIII and XIII, and thrombininduced platelet activation, resulting in a dose-dependent prolongation of activated partial thromboplastin time (aPTT). Desirudin is highly selective and has no effect on plasmin, factors IXa and Xa, tissue plasminogen activator, activated protein C, trypsin, chymotrypsin or complement activation pathways. Bleeding complications reported with the use of desirudin in patients undergoing hip-replacement surgery are similar to those reported with heparin and enoxaparin.

Lepirudin is a direct thrombin inhibitor obtained by recombinant technology from the medicinal leech and used for treatment of heparin-induced thrombocytopenia (HIT). Lepirudin was the first direct thrombin inhibitor approved and most frequently used for the treatment of patients with HIT. The efficacy of lepirudin for HIT has been shown to improve general outcomes in patients with HIT, reducing a primary composite endpoint of new thrombosis, all-cause amputation, and all-cause death. Lepirudin forms a stable non-covalent complex with alpha-thrombin, thereby abolishing its ability to cleave fibrinogen and initiate the clotting cascade. It is a highly potent, selective, and essentially irreversible inhibitor of thrombin and clot-bond thrombin. Lepirudin is identical to natural hirudin except for substitution of leucine for isoleucine at the N-terminal end of the molecule and the absence of a sulfate group on the tyrosine at position 63.

Edoxaban (DU-176b, trade names Savaysa, Lixiana) is a selective factor Xa inhibitor reduces thrombin generation and thrombus formation and is an orally bioavailable anticoagulant drug. It was developed by Daiichi Sankyo to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF) and for the treatment of deep vein thrombosis and pulmonary embolism following 5-10 days of initial therapy with a parenteral anticoagulant.

Dabigatran (Pradaxa, Prazaxa) is an anticoagulant medication that can be taken by mouth. FDA approved on October 19, 2010. Dabigatran directly inhibits thrombin in a concentration-dependent, reversible, specific, and competitive manner which results in a prolongation of aPTT (partial thromboplastin time), ECT (Ecarin clotting time), and TT (thrombin time). It may increase INR but this laboratory parameter is relatively insensitive to the activity of dabigatran. Dabigatran is indicated for the prevention of venous thromboembolic events in patients who have undergone elective hip or knee replacement surgery (based on RE-NOVATE, RE-MODEL, and RE-MOBILIZE trials). In 2010, it was approved in the US and Canada for prevention of stroke and systemic embolism in patients with atrial fibrillation (approval based on the RE-LY trial). Contraindications: severe renal impairment (CrCL < 30 ml/min); haemorrhagic manifestations, bleeding diathesis or spontaneous or pharmacologic impairment of haemostasis; lesions at risk of clinically significant bleeding (e.g. extensive cerebral infarction (haemorrhagic or ischemic) in the last 6 months, active peptic ulcer disease); concomitant treatment with P-glycoprotein inhibitors (e.g. oral ketoconazole, verapamil); and those with known hypersensitivity to dabigatran, dabigatran etexilate or any ingredient used in the formulation or component of the container. As of December 2012, dabigatran is contraindicated in patients with mechanical prosthetic heart valves.

Fondaparinux is a synthetic and specific inhibitor of activated Factor X (Xa). By selectively binding to antithrombin III (ATIII), fondaparinux sodium potentiates (about 300 times) the innate neutralization of Factor Xa by ATIII. Neutralization of Factor Xa interrupts the blood coagulation cascade and thus inhibits thrombin formation and thrombus development. Fondaparinux is indicated for the prophylaxis of deep vein thrombosis (DVT), which may lead to pulmonary embolism (PE): in patients undergoing hip fracture surgery, including extended prophylaxis; in patients undergoing hip replacement surgery; in patients undergoing knee replacement surgery; in patients undergoing abdominal surgery who are at risk for thromboembolic complications. The most serious adverse reactions reported with Fondaparinux are bleeding complications and thrombocytopenia. Agents that may enhance the risk of hemorrhage should be discontinued prior to initiation of therapy with Fondaparinux unless these agents are essential.