Differentiation of the Low-Molecular-Weight Heparins

Eric Racine, Pharm.D.


Pharmacotherapy. 2001;21(6s) 

In This Article


The LMWHs are distinct compounds that possess unique chemical, pharmacokinetic, and pharmacodynamic profiles. Each agent has dissimilar antithrombotic activities, which are reflected by antithrombin- (anti-Xa and anti-IIa ratio) and non-antithrombin-mediated actions. The LMWHs have shown divergent results in clinical trials; it is not possible to draw conclusions with regard to their relative clinical efficacies. As a result, several national organizations support the concept that the LMWHs are distinct entities and are not therapeutically interchangeable. In the absence of comparative studies, clinical results of one molecule should not be extrapolated to another. An evidence-based approach is necessary for selecting a LMWH. Treatment decisions should be based on the available safety and efficacy data for each LMWH. Agents should be prescribed only for those indications for which they have been shown to be effective and only at dosages that have been studied. Each LMWH should be considered unique until scientifically sound comparative trials are performed.


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