Best practice & research. Clinical haematology
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In the past decade, several new oral anticoagulants (NOACs) have been studied and approved for the prophylaxis and treatment of arterial and venous thromboembolism. These agents were shown to be as effective as or better than warfarin and resulted in comparable or lower bleeding rates than warfarin. Specific antidotes for the reversal of the anticoagulant effect of these drugs, such as monoclonal antibodies against the direct thrombin inhibitor dabigatran or recombinant Xa-analog in the case of factor Xa inhibitors, are still being investigated in early clinical trials. ⋯ Activated prothrombin complex concentrate seems promising for the reversal of dabigatran, while non-activated prothrombin complex concentrates have potential for the reversal of anti-factor Xa. The risk of thromboembolic complications requires careful evaluation. In this article, the evidence- or the lack of it - supporting the use of the different prohemostatic agents for the management of bleeding and for reversal of the different classes of NOACs is discussed.
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Best Pract Res Clin Haematol · Jun 2013
ReviewNovel oral anticoagulants for thromboprophylaxis after orthopaedic surgery.
The direct thrombin inhibitor, dabigatran, and the selective factor Xa inhibitors, rivaroxaban and apixaban, are new oral anticoagulants that are approved in many countries for prevention of venous thromboembolism in patients undergoing elective hip or knee arthroplasty. All have a rapid onset of action, a low potential for food and drug interactions and a predictable anticoagulant effect that obviates the need for routine coagulation monitoring. ⋯ This review summarizes the pharmacology, clinical trial results, bleeding risk and practical use of these new oral anticoagulants in clinical orthopaedic practice. Potential issues to be considered when using these oral anticoagulants include renal impairment, potential drug interactions, neuraxial anaesthesia and management of bleeding.
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The risk of venous thrombosis extends for an indeterminate length of time following admission to hospital with a medical or surgical condition. Observational studies in surgery show this risk extends for months and perhaps more than one year, for medical patients the risk extends for at least several weeks. Large bodies of evidence support the heightened risk status of hospitalised surgical and medical patients, and that prophylactic measures significantly reduce the risk of thrombosis. ⋯ Hence no therapies are approved for prolonged thromboprophylaxis in medical patients. In this area there have been one phase III study of low molecular weight heparin and two completed phase III studies of NOACs. This article briefly summarises our understanding of the background to preventing venous thromboembolism in hospitalised medical patients and reviews the details of the studies using NOACs.
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Best Pract Res Clin Haematol · Jun 2013
ReviewNew oral anticoagulants for the treatment of venous thromboembolism.
New oral anticoagulants, acting either as direct factor-Xa or thrombin inhibitors, have been evaluated for the acute and long-term treatment of venous thromboembolism (VTE). Dabigatran and rivaroxaban are as effective as conventional therapy (heparin/vitamin K antagonists) without safety concerns. Rivaroxaban allows a single-drug regimen even in patients with pulmonary embolism, while dabigatran requires 5-7 days of initial heparin treatment. ⋯ Considering both efficacy and bleeding complications, all these agents have a favorable net clinical benefit. Dabigatran is as effective and safe as warfarin for the extended treatment of VTE. It is conceivable that the new oral anticoagulants will become the standard therapy for VTE in the next years.