Gallus A S
Med J Aust. 1985 Jan 7;142(1):41-7.
The biochemistry of platelets is surprisingly complex, and offers the opportunity for numerous platelet-aggregation inhibiting ("antiplatelet") drugs to interfere with different aspects of their metabolism and function. Thus, aspirin inhibits platelet aggregation by irreversibly inactivating cyclo-oxygenase, a key enzyme in platelet prostaglandin metabolism, while the other nonsteroidal anti-inflammatory drugs and sulphinpyrazone cause reversible and dose-dependent inhibition of the same enzyme. Dipyridamole can inhibit both platelet adhesion and aggregation by raising the platelet cyclic AMP level through phosphodiesterase inhibition. The use of aspirin, sulphinpyrazone, and dipyridamole as antithrombotic agents has now been extensively evaluated. In general, treatment with these drugs has been more likely to prevent arterial than venous thromboembolism, and aspirin or the combination of aspirin and dipyridamole has been more effective in this respect than has sulphinpyrazone. Recent evidence strongly suggests that aspirin reduces the risk of non-fatal myocardial infarction in patients with unstable angina, and that the administration of aspirin in combination with dipyridamole significantly improves graft patency after aortocoronary bypass. Aspirin also appears to reduce the likelihood of stroke or death in men with transient cerebral ischaemic attacks.
血小板的生物化学过程出奇地复杂，这为众多抑制血小板聚集（“抗血小板”）的药物提供了干扰其代谢和功能不同方面的机会。因此，阿司匹林通过不可逆地使环氧化酶失活来抑制血小板聚集，环氧化酶是血小板前列腺素代谢中的关键酶，而其他非甾体抗炎药和磺吡酮则对同一酶产生可逆的、剂量依赖性的抑制作用。双嘧达莫可通过抑制磷酸二酯酶提高血小板环磷酸腺苷水平，从而抑制血小板黏附和聚集。目前已对阿司匹林、磺吡酮和双嘧达莫作为抗血栓药物的应用进行了广泛评估。一般来说，使用这些药物治疗更有可能预防动脉血栓栓塞而非静脉血栓栓塞，在这方面，阿司匹林或阿司匹林与双嘧达莫的联合应用比磺吡酮更有效。最近的证据有力地表明，阿司匹林可降低不稳定型心绞痛患者非致命性心肌梗死的风险，并且阿司匹林与双嘧达莫联合给药可显著提高主动脉冠状动脉搭桥术后移植物的通畅率。阿司匹林似乎还能降低短暂性脑缺血发作男性发生中风或死亡的可能性。
