A study was designed to compare the effects of cimetidine, ranitidine, and antacids on esophageal pH levels.

Forty-five patients with gastro-esophageal acid reflux, confirmed by 3-hour postprandial metered pH measurements, were randomized into three treatment groups. The first group received cimetidine 1 g/day, the second one was administered ranitidine 300 mg/day, and the third one received 60 ml/day of an antacid. The patients were retested under treatment with 3-hour postprandial metered pH and prolonged 20-hour metered pH, and the 3-hour postprandial metered pH was compared with the pretreatment values. The 20-hour postprandial metered pH test was compared with the results from 43 control (untreated) subjects who had gastro-esophageal acid reflux.

• There was a significant decline in acid reflux with all three drugs on 3-hour postprandial comparison.
• The 20-hour measurement also showed a significant decline in the number of acid reflux episodes with all the three drugs, in comparison with the controls.
• Ranitidine was associated with a significant decrease in the percentage of time with acid pH.
• There were no significant differences in the comparison of results for the treated patients, other than for the percentage of time below pH 2 for 20 hours. It was found to be significantly lower for ranitidine.

All three treatment regimens were found to be effective with the results favoring ranitidine.

Source: Desechalliers JP, Galmiche JP, Touchais JY, et al. Ranitidine, cimetidine, antacids, and gastro-oesophageal reflux: results of a 20-hour oesophageal pH study. Int J Clin Pharmacol Res. 1984;4(3):217-22.