Items in FPM with MESH term: Warfarin
Evidence-Based Adjustment of Warfarin (Coumadin) Doses - Point-of-Care Guides
Warfarin for Prevention of Ischemic Stroke Recurrence? - FPIN's Clinical Inquiries
Predicting the Risk of Bleeding in Patients Taking Warfarin - Point-of-Care Guides
ABSTRACT: Factors associated with an increased risk of thromboembolic events in patients with atrial fibrillation (AF) include increasing age, rheumatic heart disease, poor left ventricular function, previous myocardial infarction, hypertension and a past history of a thromboembolic event. Patients with AF should be considered for anticoagulation or antiplatelet therapy based on the patient's age, the presence of other risk factors for stroke and the risk of complications from anticoagulation. In general, patients with risk factors for stroke should receive warfarin anticoagulation, regardless of their age. In patients who are under age 65 and have no other risk factors for stroke, either aspirin therapy or no therapy at all is recommended. Aspirin or warfarin is recommended for use in patients between 65 and 75 years of age with no other risk factors, and warfarin is recommended for use in patients without risk factors who are older than 75 years of age.
ABSTRACT: Warfarin is the oral anticoagulant most frequently used to control and prevent thromboembolic disorders. Prescribing the dose that both avoids hemorrhagic complications and achieves sufficient suppression of thrombosis requires a thorough understanding of the drug's unique pharmacology. Warfarin has a complex dose-response relationship that makes safe and effective use a challenge. For most indications, the dose is adjusted to maintain the patient's International Normalized Ratio (INR) at 2 to 3. Because of the delay in factor II (prothrombin) suppression, heparin is administered concurrently for four to five days to prevent thrombus propagation. Loading doses of warfarin are not warranted and may result in bleeding complications. Interactions with other drugs must be considered, and therapy in elderly patients requires careful management. Current dosing recommendations are reviewed, and practical guidelines for the optimal use of warfarin are provided.
Self-Monitoring and Self-Management of Anticoagulation Therapy - Cochrane for Clinicians
ABSTRACT: The American College of Chest Physicians provides recommendations for the use of anticoagulant medications for several indications that are important in the primary care setting. Warfarin, a vitamin K antagonist, is recommended for the treatment of venous thromboembolism and for the prevention of stroke in persons with atrial fibrillation, atrial flutter, or valvular heart disease. When warfarin therapy is initiated for venous thromboembolism, it should be given the first day, along with a heparin product or fondaparinux. The heparin product or fondaparinux should be continued for at least five days and until the patient’s international normalized ratio is at least 2.0 for two consecutive days. The international normalized ratio goal and duration of treatment with warfarin vary depending on indication and risk. Warfarin therapy should be stopped five days before major surgery and restarted 12 to 24 hours postoperatively. Bridging with low-molecular-weight heparin or other agents is based on balancing the risk of thromboembolism with the risk of bleeding. Increasingly, self-testing is an option for selected patients on warfarin therapy. The ninth edition of the American College of Chest Physicians guidelines, published in 2012, includes a discussion of anticoagulants that have gained approval from the U.S. Food and Drug Administration since publication of the eighth edition in 2008. Dabigatran and apixaban are indicated for the prevention of systemic embolism and stroke in persons with nonvalvular atrial fibrillation. Rivaroxaban is indicated for the prevention of deep venous thrombosis in patients undergoing knee or hip replacement surgery, for treatment of deep venous thrombosis and pulmonary embolism, for reducing the risk of recurrent deep venous thrombosis and pulmonary embolism after initial treatment, and for prevention of systemic embolism in patients with nonvalvular atrial fibrillation.