Early effects of Lansoprazole orally disintegrating tablets on intragastric pH in CYP2C19 extensive metabolizers

AIM: To compare rabeprazole (RPZ; 10 mg) with Lansoprazole orally disintegrating tablets (LPZ; 30 mg OD) in terms of antisecretory activity and blood drug concentration after a single dose. METHODS: Eight H pylori-negative cytochrome P450 (CYP) 2C19 extensive metabolizers were assigned to receive a single oral dose of RPZ 10 mg or LPZ 30 mg OD. Twelve hour intragastric pH monitoring was perform- ed on the day of treatment. Blood samples were also collected after the administration of each drug. RESULTS: LPZ 30 mg OD induced a significantly earlier rise in blood drug concentration than RPZ 10 mg; consequently, LPZ 30 mg OD induced a significantly earlier rise in median pH in the third and fourth hours of the study. CONCLUSION: In H pylori-negative CYP2C19 extensive metabolizers, LPZ 30 mg OD induced a significantly faster inhibition of gastric acid secretion than RPZ 10 mg.

Bravo capsule system optimizes intragastric pH monitoring over prolonged time:Effects of ghrelin on gastric acid and hormone secretion in the rat

AIM: To evaluate measurements of intragastric pH with the Bravo capsule system over a prolonged time.METHODS: A Bravo capsule was placed inside the rat gastric body and pH was studied for periods up to five consecutive days.For comparison,a gastric fistula model was used.Effects of ghrelin and esomeprazole,with or without pentagastrin,on gastric pH were studied.In addition,effects of esomeprazole on plasma ghrelin,gastrin and somatostatin were analyzed.RESULTS: All rats recovered after surgery.The average 24-h pH during free feeding was 2.3 ± 0.1 (n = 20) with a variation of 18% ± 6% over 5 d.Ghrelin,2400 pmol/kg,t.i.d.increased pH from 1.7 ± 0.1 to 3.1 ± 0.3 (P < 0.01) as recorded with the Bravo system.After esomeprazole (1 mg/kg,3 mg/kg and 5 mg/kg) there was a dose-dependent pH increase of maximally 3.4 ± 0.1,with day-to-day variation over the entire period of 8% ± 3%.The fistula and pH studies generated similar results.Acid inhibition with esomeprazole increased plasma ghrelin from 10 ± 2 pmol/L to 65 ± 26 pmol/L (P < 0.001),and somatostatin from 10 ± 2 pmol/L to 67 ± 18 pmol/L (P < 0.001).CONCLUSION: pH measurements with the Bravo capsule are reliable,and comparable to those of the gastric fistula model.The Bravo system optimizes accurate intragastric pH monitoring over prolonged periods and allows both short-and long-term evaluation of effects of drugs and hormones.

Early effects of oral administration of omeprazole and roxatidine on intragastric pH

Objective： The ideal medication for the treatment of acid-related diseases, e.g., peptic ulcers, stress- related gastric bleeding, functional dyspepsia, and gastroesophageal reflux disease, should have a rapid onset of action to promote hemostasis and relieve the symptoms. The aim of our study was to investigate the inhibitory effects on gastric acid secretion of a single oral administration of a proton pump inhibitor, omeprazole 20 mg, and an H2-receptor antagonist, roxatidine 75 mg. Methods： Ten Heficobacterpylori-negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 6 h after single oral admini- stration of omeprazole 20 mg and roxatidine 75 mg. Each administration was separated by a 7-d washout period. Results： During the 6-h study period, the average pH after administration of roxatidine was higher than that after administration of omeprazole （median： 4.45 vs. 2.65; P=0.0367）. Also during the 6-h study period, a longer duration of maintenance at pH above 2, 5, and 6 was observed after administration of roxatidine 75 mg than after administration of omeprazole 20 mg （median： 90.6% vs. 55.2%, P=-0.0284; 43.7% vs. 10.6%, P=0.0125; 40.3% vs. 3.3%, P=0.0125; respectively）. Conclusions： In Helicobacter pylori-negative healthy male subjects, oral administration of roxatidine 75 mg increased the intragastric pH more rapidly than that of omeprazole 20 mg.

Effect of domperidone therapy on nocturnal dyspeptic symptoms of functional dyspepsia patients

AIM:To investigate the incidence of nocturnal dyspeptic symptoms in patients with functional dyspepsia(FD) and whether prokinetic drugs can alleviate them. METHODS:Eighty-five consecutive Chinese patients with FD were included in this study.One week after single-blinded placebo run-in treatment,baseline nocturnal intragastric pH,bile reflux and nocturnal dyspeptic symptoms of eligible patients,including epigastric pain or discomfort,abdominal distention and belching, were investigated with questionnaires.Patients exhibiting nocturnal dyspeptic symptoms were randomly and double-blindly assigned to domperidone group or placebo group.Nocturnal intragastric pH and percentage of duodenogastric bile reflux time were determined after treatment. RESULTS:Of the 85 FD patients,2 females withoutnocturnal symptoms,who responded to placebo run-in treatment,were excluded from the study,30(36.1%) exhibited nocturnal dyspeptic symptoms with increased duodenogastric bile reflux time(intragastric bilirubin absorbance>0.14)and mean gastric pH(confirming the existence of bile reflux)(P=0.021,0.023) at night were included in the study.Of these 30 patients,21(70%)had overt nocturnal duodenogastric bile reflux,which was significantly higher than that of those without nocturnal symptoms(P=0.026).The 30 patients were allocated to domperidone group or placebo group(n=15).The nocturnal duodenogastric bile reflux and gastric pH were significantly decreased after domperidone treatment(P=0.015,0.021).The severity score of nocturnal dyspeptic symptoms was also significantly decreased after domperidone treatment (P=0.010,0.015,0.026),which was positively correlated with the reduced nocturnal bile reflux or gastric pH(r=0.736,0.784,0.753 or r=0.679,0.715,0.697, P=0.039,0.036,0.037 or P=0.043,0.039,0.040). CONCLUSION:A subgroup of Chinese FD patients show overt nocturnal dyspeptic symptoms,which may be correlated with the excessive nocturnal duodenogastric bile reflux.Domperidone therapy can alleviate these symptoms.