Horton M A, Amos R J, Jones R J
Scand J Haematol. 1983 Jul;31(1):15-9. doi: 10.1111/j.1600-0609.1983.tb02130.x.
The in vivo and in vitro effects on the aggregatory response of human platelets to ADP and collagen of a series of imidazole and non-imidazole histamine H2 receptor antagonists, and imidazole derivatives, have been studied. Bolus i.v. administration of the antagonists cimetidine and oxmetidine was without effect. However, inhibition of platelet aggregation was observed in vitro with oxmetidine, metiamide and to a lesser extent burimamide, but not with cimetidine or the non-imidazole antagonist ranitidine. Of the imidazole derivatives only imidazole and its 1-methyl analogue significantly affected platelet aggregation. The relationship between potency as a histamine H2 receptor antagonist, the presence of an imidazole ring structure and the antiaggregatory effectiveness of these compounds is discussed. Although certain antagonists clearly inhibit platelet aggregation in vitro, effects are only seen at drug concentrations exceeding those achieved under normal therapeutic conditions; thus the clinical significance of these observations remains to be determined.
已经研究了一系列咪唑和非咪唑类组胺H2受体拮抗剂以及咪唑衍生物对人血小板对ADP和胶原聚集反应的体内和体外作用。静脉推注拮抗剂西咪替丁和奥米替丁没有效果。然而，在体外观察到奥米替丁、甲硫米特可抑制血小板聚集，布立马胺的抑制作用较小，但西咪替丁或非咪唑拮抗剂雷尼替丁则无此作用。在咪唑衍生物中，只有咪唑及其1-甲基类似物显著影响血小板聚集。讨论了作为组胺H2受体拮抗剂的效力、咪唑环结构的存在与这些化合物的抗聚集有效性之间的关系。虽然某些拮抗剂在体外能明显抑制血小板聚集，但只有在药物浓度超过正常治疗条件下达到的浓度时才会出现这种作用；因此，这些观察结果的临床意义尚待确定。
