Ordinary heparin sodium is a mucopolysaccharide sulfate extracted from animals, while low molecular weight heparin sodium is produced by the decomposition or degradation of ordinary heparin.

　　Low molecular weight heparin sodium is commonly found in enoxaparin sodium, nardonheparin sodium and dapheparin sodium. The differences are as follows: different preparation technology, different molecular structure and molecular weight, different efficacy and safety. Low molecular weight heparin mainly affected the activity of coagulation factor Xa, but had little effect on thrombin and other coagulation factors. Thus, the antithrombotic effect of heparin is maintained and the risk of bleeding is reduced.

　　Heparin binds to platelets mainly through antithrombin III, inhibits the formation of thrombin on the surface of platelets, and inhibits the aggregation and release of platelets.