Tomlinson B, Prichard B N, Graham B R, Walden R J
Department of Clinical Pharmacology, University College, London.
Clin Investig. 1992;70 Suppl 1:S27-36. doi: 10.1007/BF00207608.
Animal work has shown that carvedilol is a nonselective beta-blocking drug. It has a vasodilator action from alpha-receptor blockade, but there is evidence that it has further action to relax smooth muscle, possibly from calcium channel antagonism. Carvedilol is lipid soluble and 25% bioavailable, and it has a half-life of about 7 h. It lowers blood pressure at rest and reduces the tachycardia and the rise of blood pressure on exercise. It reduces the level of blood pressure reached during isometric exercise or the cold pressor test. Cardiac output at rest is maintained, and the haemodynamics in the compromised heart is improved. It has an important peripheral vasodilator action, peripheral flow being maintained to important organs, e.g. kidneys, despite the fall in blood pressure. Exercising renin and noradrenaline levels are increased, as are the latter at rest. Carvedilol is lipid neutral. Carvedilol shifts the dose-response curve to isoprenaline to the right, as well as to alpha-stimulants such as phenylephrine. Responses to angiotensin are little affected. The ratio of beta- to alpha-blockade has been found to be 7.6 for 50 mg and 12.5 for 100 mg of carvedilol. There is no evidence of a decline in alpha-blockade after 1 week of continuous administration.
动物实验表明，卡维地洛是一种非选择性β受体阻滞剂。它因α受体阻滞而具有血管舒张作用，但有证据表明它还有进一步舒张平滑肌的作用，可能是通过钙通道拮抗作用。卡维地洛脂溶性好，生物利用度为25%，半衰期约为7小时。它能降低静息血压，减少运动时的心动过速和血压升高。它能降低等长运动或冷加压试验时达到的血压水平。静息心输出量得以维持，受损心脏的血流动力学得到改善。它具有重要的外周血管舒张作用，尽管血压下降，但仍能维持重要器官（如肾脏）的外周血流。运动时肾素和去甲肾上腺素水平升高，静息时去甲肾上腺素水平也升高。卡维地洛对脂质无影响。卡维地洛使异丙肾上腺素的剂量反应曲线右移，对苯肾上腺素等α受体激动剂的反应也右移。对血管紧张素的反应影响不大。已发现50毫克卡维地洛的β与α阻滞比值为7.6，100毫克卡维地洛的该比值为12.5。连续给药1周后，没有证据表明α阻滞作用减弱。
