Low-molecular-weight heparins

Low-molecular-weight heparins (LMWH) are a new group of parenteral anticoag ulants. They represent a major clinical advance in anticoagulation since th e identification of unfractionated heparin (UFH) in 1922 and the introducti on of the synthetic coumarin derivative, warfarin, in 1948. Their predictab le pharmacokinetics, increased bioavailability, and longer plasma half-lift allow for once- or twice-daily dosing and eliminate the need for routine l aboratory monitoring. This simplified administration stands to alter the cl inical practice of anticoagulation. This review highlights recent clinical trials and focuses on studies comparing LMWH with the other two major antic oagulants: UFH and coumadin.