Heparin (including heparin sodium, heparin calcium, low molecular weight heparin), are anticoagulants.

　　(1) Ordinary (standard) heparin is extracted from pig or sheep mucosa with an average molecular weight of 15.000 and is fairly stable.

　　(2) Usually the molecular weight of less than 6000 is called low molecular weight heparin. Compared with ordinary heparin, low molecular weight heparin has a longer half-life, better antithrombotic effect, and a weaker tendency of anticoagulant bleeding, which tends to replace ordinary heparin. In recent years, the commonly used clinical products are: dapheparin sodium (Pharammine), enoxapin sodium (Exai), low molecular weight heparin calcium (fast and fast, natronheparin calcium).

　　(3) Currently, heparin with low anticoagulant activity, modified heparin and heparin-like preparations are being further studied. These drugs are characterized by low anticoagulant activity, high antithrombotic resistance, long action time and less bleeding effect, which are promising for development.

　　Heparin sodium: This strain is a sodium salt of glucosamine sulfate extracted from the intestinal mucosa of pigs. It is a viscocarbohydrate substance and plays an anticoagulant role by activating antithrombin Ⅲ(AT-Ⅲ). It affects all three stages of the clotting process, has an anticoagulant effect in vivo and in vitro, and can prolong the clotting time, prothrombin time and thrombin time. It is not absorbed orally and is well absorbed when given subcutaneously, intramuscularly or intravenously.

　　The effect of heparin calcium and heparin sodium is similar, but after subcutaneous injection of this product does not reduce the calcium colloid in the intercellular capillaries, nor does it change the vascular permeability, basically overcomes the side effect that heparin sodium is easy to cause bleeding by subcutaneous injection. This product also has obvious anti-renin and anti-aldosterone activities.