Initiate anticoagulation therapy for:
Primary prophylaxis in patients with atrial fibrillation or mechanical heart valves to prevent systemic embolism and stroke
Primary prevention of VTE in patients with medical illnesses
Secondary prevention of VTE, treating with warfarin for at least 3 months
Use direct thrombin inhibitors (danaparoid, lepirudin, argatroban, bivalirudin) in the setting of heparin-induced thrombocytopenia.
Note that bleeding is a major risk and complication of anticoagulation therapy; bleeding from UFH is reversed with protamine, 1 mg, to neutralize each 100 U of UFH but bleeding associated with LMWH is only partially reversible.
Note that bleeding is the major adverse event associated with fondaparinux. Treat bleeding due to fondaparinux with supportive measures, such as fresh frozen plasma and factor concentrates or recombinant factor VIIa supplemented with vitamin K, as there are no specific therapies.
Monitor for heparin-induced thrombocytopenia by obtaining a platelet count frequently during the initial 2 weeks of therapy, usually every 2 to 3 days.
Treat heparin-induced thrombocytopenia by discontinuing all heparin products, including subcutaneous heparin and heparin flushes and substitute an alternative anticoagulant, such as a direct thrombin inhibitor (argatroban or lepirudin).
Note that the major adverse events associated with warfarin include bleeding, skin necrosis, and purple toe syndrome due to cholesterol embolization.
Note that the major risk associated with direct thrombin inhibitors is bleeding.
Note that lepirudin is associated with serious allergic reactions that may occur with the initial dose or with re-exposure.
Note that lepirudin is renally excreted and requires dose adjustment in patients with renal impairment, and that argatroban is metabolized by the liver and requires dose adjustment in patients with hepatic impairment.
Note that dabigatran is contraindicated in people with severe renal impairment, active clinically significant bleeding, organic lesions at risk for bleeding, impairment of hemostasis, and hepatic impairment.