Acid-Suppressive Effect of Rabeprazole 5 mg and 10 mg Once Daily by 24-Hour Esophageal pH Monitoring in Patients with Non-erosive Reflux Disease in Japan: A Multicenter, Randomized, Parallel-Group, Double-Blind Pharmacodynamic Study

Abstract

Acid suppression induced by rabeprazole 5 mg in patients with NERD has not been reported in the literature. The objective of this study was to investigate gastroesophageal acid suppression in NERD patients by rabeprazole 5 mg and 10 mg/day. Subjects were grade M (minimal changes) NERD patients. Twenty-two patients not responding to open label antacid therapy entered a double-blind treatment phase in which rabeprazole 5 mg or 10 mg/day for four weeks were compared. Twenty-four-hour esophageal pH monitoring was performed before and on treatment (at week 4) to assess the pharmacodynamic effect of these doses of rabeprazole. The frequency of heartburn episodes and the number of acid reflux episodes in the esophagus corresponded well in grade M NERD patients (r=0.44, P=0.042). Median percentage of time at pH<4 was 4.3% before treatment and 1.1% on treatment with rabeprazole 5 mg (change from baseline; -2.5%), whereas the median percentage of time at pH<4 in the rabeprazole 10 mg group was 7.4% before treatment and 0.5% on treatment (change from baseline; -6.6%). Likewise, treatment-related changes of median number of reflux episodes were -18.0 with rabeprazole 5 mg and -44.0 with rabeprazole 10 mg. For each esophageal pH data, no significant differences were observed between the two groups (P=0.377, P=0.077). Administration of 5 mg and 10 mg rabeprazole sufficiently inhibited pathological gastroesophageal acid reflux and relieved heartburn episodes in NERD patients who did not respond to an antacid. Further investigation would be necessary to determine proper usage of the two doses.