[Antacids--gel or tablet. A randomized, double-blind, placebo-controlled study]

A double blind placebo controlled trial was conducted to compare the effect of two antacid brands (liquid and tablet form) on fasting and postprandial intragastric pH. In 9 healthy volunteers intragastric pH was continuously recorded by solid state memory on 6 occasions. 40 mmol of each antacid was given one hour before and after a standardized meal. The time during which pH was below 3.5 during the first hour following each medication was, in the fasting state, 56.7 +/- 2.1 min. with placebo tablets, 30.7 +/- 8.0 min. (p 0.05) with magaldrate tablets, 26.6 +/- 8.0 min. (p less than 0.01) with Al-Mg-hydroxide tablets, 46.1 +/- 6.1 min. with placebo liquid, 18.4 +/- 5.2 min. (p less than 0.01) with magaldrate liquid, and 21.5 +/- 6.2 min. (p less than 0.01) with Al-Mg-hydroxide liquid. Postprandially the respective periods of time were 48.3 +/- 4.9 min. with placebo tablets, 45.4 +/- 4.6 min. (n.s.) with magaldrate tablets, 48.9 +/- 5.6 min. (n.s.) with Al-Mg-hydroxide tablets, 46.7 +/- 7.9 min. with placebo liquid, 26.6 +/- 9.3 min. (p less than 0.05) with magaldrate liquid, and 28.0 +/- 7.1 min. (p less than 0.05) with Al-Mg-hydroxide liquid. Both tested brands were equally effective. With regard to pH activity, both tested forms were more effective in fasting state than postprandially; tablets showed no measureable activity postprandially and were less effective than the liquid form. The usefulness of the usual medication of low-dosed antacids, one hour postprandially, is open to doubt.