Traditional anticoagulants: Systemic anticoagulation has been the mainstay of VTE treatment. For many decades, standard care was to start with unfractionated heparin51 or low molecular weight heparin (LMWH), then bridging to oral vitamin K antagonist (VKA) for long-term anticoagulation.52 Unfractionated heparin has been largely replaced by LMWH in most clinical situations due to the ease of outpatient administration, given subcutaneously once or twice a day, without the need for laboratory monitoring. LMWH has also been used as an alternative for chronic anticoagulation. The recommended dose for enoxaparin is 1 mg/kg every 12 hours (maximum dose 150 mg) and for dalteparin is 10,000 to 18,000 IU once a day (depending on weight).53 Of note, a previous randomized trial comparing enoxaparin at the standard doses of 1 mg/kg twice a day and 1.5 mg/kg once a day showed that the latter was associated with nearly 4-fold greater risk for nonvariceal bleeding.54
