Effects of combined use of roxatidine and pirenzepine on gastric secretion in humans.

We examined the effects of the combined use of H2-receptor antagonist (roxatidine) and muscarinic receptor antagonist (pirenzepine) by oral administration on gastric juice and acid secretion in humans. The volume, pH level, and acidity of gastric juice were determined in the sample collected at 9:00 AM 10 hr after either the oral administration of 150 mg of roxatidine or the combined administration of 150 mg of roxatidine and 50 mg of pirenzepine. Significant decrease in volume and acidity and increase in pH were observed in both roxatidine group and combined group compared with control placebo group, but significant difference were not observed in gastric pH and acidity between roxatidine group and combined group. The volume of gastric juice was decreased significantly by the combined administration in comparison with the sole administration of roxatidine. Consequently, the combined oral administration of the two agents was considered to be more effective than the sole administration of roxatidine for clinical cases which require stronger suppression of gastric secretion at the night.