[Pharmacology of heparin]

After introductory notes on the history of heparin research the chemistry of this mucopolysaccharide is described. It is shown that the chemistry of heparin cannot be exactly described by one chemical formula because heparin represents a family of compounds with different chain-length. Molecular features responsible for the high structural specificity of anticoagulant activity are described. The present status of knowledge on the mechanism of the anticoagulant action of heparin is described in detail. It is shown that basic mechanism is the acceleration of the interaction of antithrombin III with the clotting factors IXa, Xa, XIa, XIIa, and thrombin which are known to be serine proteases. The effects of heparin of platelet function, lipid composition of blood, and on fibrinolysis reflect its complex influence on hemostasis. After a description of side effects and toxicity clinically relevant data on its pharmacocinetics are given.