Effects of Omeprazole and Famotidine On Gastric Acidic Environment in Patients with Gastric Neoplasia for 4 Days After Endoscopic Submucosal Desection

Abstract

Background and Aim: Although endoscopic submucosal desection (ESD) is a curative treatment for early gastric cancer (GCA), high rates of complications such as post-ESD hemorrhage are critical, and gastric acid inhibitors are empirically administered to gastric ulcer artificially evoked by ESD. However, effects of PPIs and H2-RAs on gastric acidic environment in these patients have not been well known. The study aims are (1) to evaluate feasibility of long-term gastric pH monitoring with Bravo wireless system, (2) to demonstrate basal status of gastric acidity in GCA patients, and (3) to compare effects of PPI and H2-RA on gastric acidic environment in GCA patients resected by ESD. Methods and subjects: A pH monitoring capsule with a looped nylon string was endoscopically attached with stainless clips on the wall of the upper gastric corpus. Ambulatory pH monitoring was performed in GCA patients from one day before ESD (Pre1) to 4 days after ESD (POD1-4). Acid inhibitors were restricted one week before ESD. For POD1 and POD2, omeprazole (OMP, 20 mg × 2 /day) or famotidine (FAM, 20 mg × 2 /day) was intravenously administered to patients under nothing per os. From POD3, both inhibitors were orally administered and food intake was started. Forty patients were prospectively enrolled (20 in OMP group and 20 in FAM group). Gastric acidic environment was assessed with % time pH< 4. Results: (1) All patients were successfully pH-monitored with the system. (2) % Time pH<4 on Pre1 were comparable in OMP group (38.62+/− 35.08; mean +/− SD) and FAM group (36.4 +/−34.7). (3) % Time pH<4 on POD1 and POD2 in OMP group (20.15 ± 33.14, 13.32 ± 24.80) and FAM group (22.76 ± 16.88, 14.16 ± 19.33) comparably reduced to one half and third of those on Pre1. In contrast, those on POD3 and POD4 in OMP group (10.50 ± 24.85, 8.28 ± 21.65) were significantly (P = 0.01 and 0.001) lower than those in FAM group (36.46 ± 34.71, 42.06 ± 37.99). Conclusions: Long-term gastric pH monitoring was feasible with Bravo wireless system. GCA patients supposed to be hypoacidic or achlorhydric due to gastric atrophy still have gastric acidity under pH 4 over one third of day. Intravenously administered OMP and FAM comparably neutralize intragastric acidity, but the neutralization is not complete for 2 days after ESD. OMP is recommended as an effective acid inhibitor during the period of oral intake after ESD.