Persistent gastric-protective effect of antacid evaluated by measurement of transmucosal gastric potential difference

The aim of this study was to determine the effect of 1 week of antacid dosing on the aspirin-induced potential differences (PDs) across the gastric mucosa. The study design was double blind and randomized with crossover. Ten healthy subjects received aluminum hydroxide gel, 8 gm t.i.d., or placebo for 1 week. They then received 1 gm aspirin after an overnight fast and the PD across the mucosa was measured. Baseline potentials were the same before both treatment periods. Antacids reduced the aspirin-induced PDs. The mean (+/- SD) maximal PD was 27.4 +/- 1.7 mV with placebo vs. 10.7 +/- 2.2 mV with antacids (p less than 0.001). Recovery time was 65.5 +/- 5.2 minutes with placebo vs. 29.0 +/- 6.7 minutes with antacids (p less than 0.001). These results suggest the effect is due to a longer-term cytoprotective property of antacids rather than to acid-neutralizing activity.