Differentiation of low molecular weight heparins in treatment of acute deep vein thrombosis

The safety and efficacy of several low molecular weight heparins (LMWHs) in the treatment of deep vein thrombosis have recently been established. The available LMWHs differ in physicochemical properties, in vitro activity and pharmacodynamics, but it is not yet known what if any effect these differences exert on clinical efficacy. Clinical trials have compared individual LMWHs with unfractionated heparin or different dose regimens of the same LMWH, but no comparisons between individual LMWHs have been performed. Variations in dosing regimens and patient populations among the trials make meaningful comparisons between individual LMWH efficacy and safety profiles problematic. Thus, while it is likely there are clinical safety and efficacy differences between the LMWH treatment regimens, it will not be possible to characterize one agent as superior to another until head-to-head trials are reported.