Alginic acid decreases postprandial upright gastroesophageal reflux. Comparison with equal-strength antacid

This study tested the hypothesis that (alginic) acid may have a preferential effect on reflux in the upright position. We evaluated the effect of a compound containing alginic acid plus antacid (extra-strength Gaviscon) versus active control antacid with equal acid-neutralizing capacity on intraesophageal acid exposure following a high-fat meal (61% fat: sausage, egg, and biscuit). In random sequence, each of the 10 volunteers received either alginic acid-antacid or control antacid immediately following and 1, 2, and 3 hr after the meal. The sequence was repeated for both test drugs in the supine and upright positions with constant pH monitoring. Alginic acid-antacid significantly decreased postprandial reflux in the upright position compared to an equal amount of antacid. This effect did not occur in the supine position. These findings support the hypothesis that alginic acid is primarily effective in the upright position and the clinical observations of the effectiveness of alginic acid on daytime reflux symptoms.