Intragastric volatile N-nitrosamines, nitrite, pH, and Helicobacter pyloriduring long-term treatment with omeprazole

Background & Aims: This study evaluated the effect of long-term gastric aci d suppressive therapy with omeprazole on intragastric levels of carcinogeni c N-nitrosamines and related parameters. Methods: Forty-five patients on lo ng-term omeprazole medication (mean, 35 months) and :13 healthy subjects wi thout medication participated. Volatile N-nitrosamines were determined in g astric juice and urine. Intragastric pH, nitrite, nitrate, and H. pylori st atus were determined. DNA isolated from gastric biopsy specimens was analyz ed for precarcinogenic alkyl-DNA adducts. Results. The intragastric pH in p atients was significantly higher compared with controls (P = 0.0001). Gastr ic nitrite levels in patients were nonsignificantly higher. There was no di fference in total levels of intragastric volatile N-nitrosamines between pa tients and controls, however, urinary N-nitrosodimethylamine excretion was higher in patients (P = 0.001). On omeprazole, Helicobacter pylori-positive vs. -negative patients had a nonsignificantly higher intragastric nitrite level and higher urinary N-nitrosodimethylamine excretion. No alkyl-DNA add ucts could be detected in gastric epithelium. Conclusions: Increased intrag astric pH caused by long-term treatment with omeprazole does not result in increased intragastric levels of nitrite and volatile N-nitrosamines. The s ignificantly higher urinary N-nitrosamine excretion implies the risk of inc reased endogenous formation of N-nitrosamines during long-term omeprazole t reatment. This risk may be higher in H. pylori-positive patients.