Heparin anticoagulant action

Heparin, which has an anticoagulation action, may give rise to heparin-induced thrombocytopenia, which is an immune-mediated condition that usually develops 5-10 days after the administration of the drug. When heparin is used, a platelet count should be measured before treatment and if administration is repeated, platelet counts should be monitored regularly. Signs of thrombocytopenia include a reduction in platelet count. It may present with spontaneous haemorrhage and heparin should be stopped. Factor VIII is used in the treatment and prophylaxis of haemorrhage in patients with haemophilia. 

Oral anticoagulant-induced hypoprothrombinemia V iamn K will not counteract the anticoagulant action of heparin. 

The anticoagulation action of heparin depends on the presence of a specihc ser me, protease inhibitor (ser-pin) of thrombin, antithrombin III, in normal blood. 

B. Thrombocytopenia is a frequent side effect association with heparin. This reduction in the level of circulating platelets increases bleeding. Purple toes are encountered during warfarin therapy. Heparin may be administered to pregnant mothers without risk to the fetus. Heparin requires antithrombin III for its anticoagulant action, but does not increase the level of this protein in the blood. 

Excessive anticoagulant action of heparin is treated by discontinuance of the drug. If bleeding occurs, administration of a specific antagonist such as protamine sulfate is indicated. Protamine is a highly basic peptide that combines with heparin as an ion pair to form a stable complex devoid of anticoagulant activity. For every 100 units of heparin remaining in the... 

The year of 1961, when Vincent Gott11 observed the inhibition of thrombus formation by immobilized heparin for the first time, was marked as the second birth date of heparin, since it was for the first time isolated from liver tissue. Its anticoagulant action was detected in 1892. Although more than 20 years have passed since Gott s publication, there is still much confusion concerning the views on the mechanism of enhanced thromboresistance of heparin-modified polymers, which greatly hinders the introduction of HCP into clinical practice. 

Fig. 9 demonstrates the proportionality between the amount of immobilized trypsin and the lytic activity of the trypsin-containing material. The higher lytic efficiency of the binary trypsin-heparin systems seems unexpected (cf. curves 2 and 4, and 5 and 6 of Fig. 9), however. Thus, immobilized trypsin and heparin of the described polymeric materials mutually affected each other. This is manifested by the enhanced anticoagulant action of heparin promoted by trypsin and by greater lytic efficiency of trypsin provoked by heparin. 

Inhibition of immune hemolysis by berberine was described by Tanaka (505). Subcutaneous or intravenous injections of berberine either in single doses or repeatedly did not affect the number of erythrocytes, leukocytes, and the hemoglobin level of intact rabbits (506). In rabbits, with anemia induced by phenylhydrazine and toluenedia-mine, berberine had an antianemic effect. Hasegawa and Tanaka (507) did not observe any effect of berberine on the production of plasma cells. It decreased the anticoagulant action of heparin in dog and human blood in vitro (508). Morthland (509) carried out a spectrophotometric study of the interaction of nucleic acids with aminoacridine or with other basic stains including berberine. 

Damus PS, Hicks M, Rosenberg RD. Anticoagulant action of heparin. Nature 1973 246 355-357. 

Mode of action. Heparin depends for its anticoagulant action on the presence in plasma of a single chain glycoprotein, antithrombin (formerly antithrombin III), a naturally-occurring inhibitor of... 

Heparin antagonism. Heparin effects wear off so rapidly that an antagonist is seldom required except after extracorporeal perfusion for heart surgery. Protamine, a protein obtained from fish sperm, reverses the anticoagulant action of heparin, when antagonism is needed. It is as strongly basic as heparin is acidic, which explains its immediate action. Protamine sulphate, 1 mg by slow i.v. injection, neutralises about 100 units of heparin derived from mucosa (mucous) or 80 units of heparin from lung ... 

Anticoagulant Action of Heparin and Heparinoids The basic facts about the anticoagulant action of heparin are that (f) 1 to 10 pg is effective in delaying the clotting of 1 ml. of blood or plasma ... 

---