Wyeth J W, Pounder R E, Sercombe J C, Snell C C
Royal Free Hospital School of Medicine, London, UK.
Aliment Pharmacol Ther. 1998 Mar;12(3):255-61. doi: 10.1046/j.1365-2036.1998.00307.x.
H2-receptor antagonists are becoming widely available as over-the-counter medications for the treatment of heartburn and excess gastric acidity.
To determine the effects of single low doses of ranitidine on intragastric acidity.
Intragastric pH was measured for 9 h after lunch in five studies involving 24 healthy male volunteers. Antacid was given to all subjects on day 1. They then received single oral doses of a study drug 45 min after lunch on four separate occasions: placebo and either ranitidine 25 mg, 75 mg or 125 mg were given double-blind according to a predetermined randomization schedule.
During both of the post-dosing time periods (0-5 h and 5-9 h) there were significant decreases in integrated intragastric acidity for each ranitidine dose compared with placebo (P < 0.0001). There was a significant linear relationship between dose and integrated intragastric acidity with a greater decrease in acidity with increasing ranitidine doses (P < 0.0001). Compared with placebo, time with pH > 3 was significantly greater for ranitidine 75 mg and 125 mg (P < 0.001), but not ranitidine 25 mg. Results with the antacid were similar to placebo.
Using low doses of ranitidine (25, 75 or 125 mg) there was a dose-related decrease in intragastric acidity for 9 h after dosing. A single dose of antacid did not decrease intragastric acidity significantly.
H2受体拮抗剂作为非处方药物越来越广泛地用于治疗烧心和胃酸过多。
确定单次低剂量雷尼替丁对胃内酸度的影响。
在五项研究中，对24名健康男性志愿者午餐后9小时的胃内pH值进行测量。第1天给所有受试者服用抗酸剂。然后在午餐后45分钟，他们在四个不同的场合接受单次口服研究药物：根据预先确定的随机分组方案，双盲给予安慰剂以及25毫克、75毫克或125毫克雷尼替丁。
在给药后的两个时间段（0 - 5小时和5 - 9小时），与安慰剂相比，每种雷尼替丁剂量的胃内酸度积分均显著降低（P < 0.0001）。剂量与胃内酸度积分之间存在显著的线性关系，随着雷尼替丁剂量增加，酸度降低幅度更大（P < 0.0001）。与安慰剂相比，75毫克和125毫克雷尼替丁使pH > 3的时间显著延长（P < 0.001），但25毫克雷尼替丁无此效果。抗酸剂的结果与安慰剂相似。
使用低剂量雷尼替丁（25、75或125毫克）给药后9小时，胃内酸度呈剂量依赖性降低。单次剂量的抗酸剂并未显著降低胃内酸度。
