Regårdh C G, Johnsson G, Jordö L, Lungborg P, Persson B A, Rönn O
J Cardiovasc Pharmacol. 1980 Nov-Dec;2(6):715-23. doi: 10.1097/00005344-198011000-00002.
The pharmacokinetics of metoprolol and propranolol in 6 healthy volunteers were compared after an intravenous dose of 10 mg of each drug. The mean t1/2, beta was 3.6 hr for both drugs, but due to a larger volume of distribution, the total body clearance was significantly higher for metoprolol (1.20 liters/min) than for propranolol (0.81 liters/min). The individual pharmacokinetic data were used to calculate the doses required to increase the amount of each drug in the body to 10 and 20 mg at 90 and 180 min respectively after an initial intravenous dose of 5.0 mg. The effect on exercise heart rate was determined 30 min after each dose. After identical doses, the two drugs had similar beta-blocking effects in terms of reducing exercise-induced tachycardia. These effects increased with the dose administered. The plasma levels of propranolol were twice as high as those of metoprolol for identical degrees of beta-blockade. The slope of the regression line for the relationship between the beta-blocking effect and log plasma concentrations was the same for the two drugs.
在6名健康志愿者静脉注射10毫克每种药物后，比较了美托洛尔和普萘洛尔的药代动力学。两种药物的平均t1/2，β均为3.6小时，但由于分布容积较大，美托洛尔的总体清除率（1.20升/分钟）显著高于普萘洛尔（0.81升/分钟）。个体药代动力学数据用于计算在初始静脉注射5.0毫克后，分别在90分钟和180分钟时将体内每种药物的量增加到10毫克和20毫克所需的剂量。在每次给药后30分钟测定对运动心率的影响。给予相同剂量后，两种药物在降低运动诱发的心动过速方面具有相似的β受体阻滞作用。这些作用随给药剂量增加而增强。对于相同程度的β受体阻滞，普萘洛尔的血浆水平是美托洛尔的两倍。两种药物β受体阻滞作用与血浆浓度对数之间关系的回归线斜率相同。
