肝素是作为抗凝剂应用于临床的。随着对肝素研究的不断深入,取得了不少的进展,不仅已逐渐阐明肝素的抗凝作用机制,又发现了一些非抗凝方面的药理作用,而且肝素用量趋向小剂量化,用法亦多采用皮下注射。本文拟就小剂量肝素疗法的有关问题加以综述。抗凝作用机制:肝素分子的抗凝活力在于多糖链上含有硫酸盐,肝素氨基葡萄糖醛酸和其它氨基葡萄糖醛酸的区别就在于前者每个双糖单位含有2～2.5个硫酸离子,而后者只有1个;若去掉肝素链中的硫酸盐成分,则抗凝活性消失。肝素通过加强和加速抗凝血酶—Ⅲ(AT—Ⅲ)的作用,抑制凝血程序中的多个环节而发挥抗凝作用(附图)。AT—Ⅲ的最初作用靶 Heparin is used clinically as an anticoagulant. With the deepening of research on heparin, a lot of progress has been made. Not only the heparin anticoagulant mechanism has gradually been clarified, but also some non-anticoagulant pharmacological effects have been found. Moreover, the dosage of heparin tends to be smaller and more used, Subcutaneous injection. This article intends to review the relevant issues of low-dose heparin therapy. Anticoagulant mechanism: The anticoagulant activity of heparin molecules is that the polysaccharide chains contain sulfate. The difference between heparin aminoglycoside and other glucosinolates is that the former contains 2 ~ 2.5 sulfate ions per disaccharide unit, while the latter Only 1; if removed in the heparin chain of the sulfate component, the anticoagulant activity disappears. Heparin exerts anticoagulant effects by potentiating and accelerating the action of antithrombin-III (AT-III) and inhibiting multiple links in the clotting process (Figure). The initial target of AT-III