Rabeprazole delays gastric emptying of a nutrient liquid

Background: It is generally considered that gastric acid suppression delays gastric emptying of solid meals because gastric hypoacidity impairs peptic digestion and antral triturition. Rabeprazole is one of the most potent acid suppressants. We conducted this cross-over study to investigate if rabeprazole delays gastric emptying of liquid nutrients, for which peptic digestion is unnecessary. Methods: On two randomized occasions, 13 healthy male volunteers underwent the C-13-acetate breath test following ingestion of a 300 kcal-liquid meal. On one occasion, they had received 20 mg rabeprazole for the preceding 2 days and 1 h before the test. On another, they took no pretreatment. Based on 4 h breath samples, the half (CO2)-C-13 excretion time (t(1/2b)) and the time of maximal excretion (t(max)) were calculated as overall measures of gastric emptying. In addition, time profiles of gastric emptying were generated using the Wagner-Nelson analytical method, which creates the gastric emptying curve as accurately as the scintigraphy. Results: Rabeprazole significantly prolonged t(max) but unchanged t(1/2b). The gastric emptying profiles showed that rabeprazole evoked a segmental slowing of gastric emptying during 0.5-1.25 h of post-meal ingestion. Conclusions: Rabeprazole suppresses gastric emptying of a liquid nutrient 0.5 h after meal ingestion. We have speculated that: (i) rabeprazole delays gastric emptying via a mechanism other than acid-pepsin maldigestion; and (ii) rabeprazole may intensify the post-gastric feedback regulation system (> 0.5 h of post-meal).