Bruley des Varannes S, Duquesnoy C, Mamet J P, Slama A, Galmiche J P, Scarpignato C
Department of Gastroenterology & Hepatology, College of Medicine, University of Nantes, France.
Aliment Pharmacol Ther. 1998 Nov;12(11):1155-61. doi: 10.1046/j.1365-2036.1998.00403.x.
Because of their tolerance and safety, low doses of H2-receptor antagonists are now increasingly used in some countries for self-care medication of gastro-oesophageal reflux symptoms.
The purpose of this randomized, double-blind, placebo-controlled, five-way crossover study was to determine and to compare the effects of low doses of ranitidine and cimetidine both on gastric pH and on oesophageal acid exposure.
Gastric and oesophageal pH were simultaneously monitored in 20 healthy subjects using two glass pH electrodes, after placebo and single doses of ranitidine 75 mg and cimetidine 200 mg (effervescent and tablet forms), for 4 h before and after a meal.
During the fasting period, median gastric pH rose significantly with both drugs, but more rapidly with the effervescent forms; the oesophageal acid exposure was significantly decreased by all drug regimens. After the meal, although there was no significant difference in gastric pH values, oesophageal acid exposure was significantly decreased in comparison with placebo with both forms of ranitidine (P < 0.05), and also for ranitidine tablets in comparison with cimetidine tablets (P < 0.05).
Low doses of ranitidine and cimetidine increase gastric pH, with a more pronounced effect for ranitidine. Effervescent formulations of both drugs induce a slightly more rapid initial increase in pH than tablets. Ranitidine demonstrates a more prolonged effect than cimetidine and decreases oesophageal acid exposure monitored after a meal ingested 4 h after the drug intake.
由于其耐受性和安全性，低剂量的H2受体拮抗剂目前在一些国家越来越多地用于胃食管反流症状的自我护理用药。
这项随机、双盲、安慰剂对照、五交叉试验的目的是确定并比较低剂量雷尼替丁和西咪替丁对胃内pH值和食管酸暴露的影响。
使用两个玻璃pH电极，在20名健康受试者中同时监测胃和食管的pH值，分别给予安慰剂以及单剂量75mg雷尼替丁和200mg西咪替丁（泡腾片和普通片剂形式），在进食前后各监测4小时。
在禁食期间，两种药物均可使胃内pH值中位数显著升高，但泡腾片形式升高得更快；所有药物治疗方案均可使食管酸暴露显著降低。进食后，尽管胃内pH值无显著差异，但两种形式的雷尼替丁与安慰剂相比，食管酸暴露均显著降低（P<0.05），雷尼替丁片剂与西咪替丁片剂相比也有显著降低（P<0.05）。
低剂量雷尼替丁和西咪替丁可提高胃内pH值，雷尼替丁的作用更显著。两种药物的泡腾制剂比片剂使pH值初始升高略快。雷尼替丁的作用比西咪替丁更持久，并且在服药4小时后进食，可降低监测到的食管酸暴露。
