The Pharmacological Effect of Omeprazole on Water Gastric Emptying: A Study Based on an Impedance Measure

Abstract

The present study was performed to validate the accuracy of a self-designed applied-potential tomograph (APT) in measuring the cross area of a studied object and to assess the effect of omeprazole premedication on water gastric emptying (GE), based on APT. Twelve electrodes were evenly placed in a circular array around the studied subjects. Ten electrodes in a rotated order recorded the electrical current injected into paired electrodes. Based on tomography, averaged signals of changed resistivity were constructed to display the area of interest and GE curve. Six beakers of various diameters were respectively placed into a cylindrical perspex tank which was filled with saline to measure their cross areas via computer-generated diagrams of APT. One hour after either omeprazole (20 mg) or placebo premedication, 15 healthy males were ordered to consume 500 ml of test water to assess emptying for 40 min. Within 3 days, a similar procedure was repeated using the counterpart premedication. The true cross areas of the 6 beakers are 2.01, 15.9, 18.8, 30.19, 38.48 and 63.61 cm², whereas those obtained by APT were 7.9 ± 2.9, 16.7 ± 3.3, 22.4 ± 4.9, 28 ± 4.8, 48.7 ± 7.6 and 67 ± 6.1 cm², respectively (r = 0.98, p < 0.001). Valid emptying data were obtained in 73.3 and 86.6% of subjects, following placebo and omeprazole, respectively (not significant). The half emptying times were 12.7 ± 5.1 min for the placebo-treated group and 10.5 ± 3.6 min for the omeprazole-treated group, respectively (p < 0.05). The areas under the emptying curve were 1,611.5 ± 357.6 and 1,317.3 ± 316.7 arbitrary units, respectively (p < 0.01). In conclusion, our APT system is accurate for large-area measurements; acid inhibition before APT measurement does not increase the success rate but enhances water emptying. The interpretation of impedance-obtained GE should consider the acid-inhibitory effect.

Does Rabeprazole Enhance Distension-Induced Gastric Accommodation?

“…However, we think that the gastrin-related mechanism is of minor importance, because an acute 3-day pretreatment with 20 mg rabeprazole elevates serum gastrin levels only minimally [8]. Our opinion is further supported by a previous result that omeprazole does not delay but accelerates GE of water even under hypergastrinemic conditions [13]. On the other hand, reduced acid secretion is accompanied by a decreased fluid volume in the stomach.…”

“…Although PPIs have no direct effect on smooth muscle contractility, the agents have variable effects on GE. In general, PPIs delay GE of solids and calorie-containing liquids [8][9][10][11], and the drugs hasten GE of a smaller volume (\500 ml) of water ingested without solid meals [12,13]. We want to emphasize that no researchers have reported a delaying effect of PPIs on GE of water.…”

Effects of Proton Pump Inhibitors on Gastric Emptying: A Systematic Review

“…This method would not accurately reflect gastric emptying because absorption processes of a paracetamol tablet involve not only gastric emptying but also tablet dissolution [36]. The remaining three studies appear to be relevant for the pure effect of PPIs [14][15][16]. From the results of the only three studies, however, we cannot refer to any definitive conclusion at all.…”

“…Insufficient suppression due to single dosing can be responsible for the type II error, because the delaying effect of PPIs on solid emptying seems to be dose-dependent [41]. The three studies employed the single-dosing regimen [15,17,24], only one of which provided a significant result [15].…”

“…If the acid-sensitive feedback regulation is totally attenuated after PPIs, gastric emptying would be accelerated. However, the accelerated emptying with PPIs has been shown only in the two studies about the emptying of water [15,16]. The effects of acid suppression by PPIs on the proximal motility have not well been investigated.…”