Effect of Timing of Proton Pump Inhibitor Administration on Acid Suppression

<b><i>Background:</i></b> Esomeprazole has been reported to show a strong acid suppression following preprandial as compared to postprandial administration, though no known study has compared the acid suppressing effects of other proton pump inhibitors between those administrations. The aim of this study was to compare intragastric pH levels following pre- and postprandial administrations of rabeprazole and esomeprazole. <b><i>Methods:</i></b> In 15 <i>Helicobacter pylori</i>-negative healthy volunteers, we measured intragastric pH after 7 days of pre- and postprandial administrations of rabeprazole (10 mg) or esomeprazole (20 mg) using a 5-way crossover design. <b><i>Results:</i></b> Preprandial administration of esomeprazole showed stronger acid suppression than postprandial administration. The values for percent time at pH >4.0 over a 24-hour period increased from 45.3% with postprandial administration of esomeprazole to 54.4% with preprandial administration, while the percent time at pH >4.0 during daytime was increased to a greater extent from 51.4 to 66.5% with preprandial administration (p = 0.05). On the other hand, the acid suppressing effect of rabeprazole was not influenced by the timing of administration. <b><i>Conclusions:</i></b> The acid suppressing effect of esomeprazole is influenced by administration timing. In contrast, the acid suppressing effect of rabeprazole is not augmented by preprandial administration.