摘要

研究了h2受体阻断对9例正常男性胃内酸性的影响。他们的胃内容物的pH值在48小时内分别在白天每小时和夜间每小时测量一次。在这两天的研究中，受试者吃相同的食物，喝相同量的液体，抽相同数量的香烟。他们的身体活动在病房环境中不受限制。在连续血样中测定血西咪替丁和血浆胃泌素。9名受试者随机服用西咪替丁0-8-1-0 g，一天服用，另一天服用安慰剂胶囊。这种药物分为四种剂量:四名受试者在三顿正餐前服用，五名受试者在三顿正餐后服用。所有人都在睡前服用第四剂。在两个研究日均给予安慰剂的另一受试者的重复研究显示出良好的再现性(r=0-80, P < 0-01)。西咪替丁治疗降低了所有9名受试者的胃内酸性。 The decrease was similar in the two groups taking the drug before or after meals, mean 24 h intragastric hydrogen ion activity being lowered by 70 and 72% respectively. Nocturnal anacidity was recorded in only two of 45 samples. Administration of cimetidine before meals produced earlier and higher drug blood levels than post-prandial medication, but when it was taken after food the blood levels were highest at the time when the buffer capacity of the food was waning. Blood concentrations of cimetidine exceeded the secretory IC50 level for most of the time between doses. The results show that cimetidine 0-8-1-0 g/day in four divided doses produces a striking and consistent decrease of intragastric acidity. Although variation in the timing of the dose in relation to meals did not affect the decrease of acidity, the absorption data suggest that patients should take the drug after meals.