Ingrid T.M. Vermeer and colleagues from the University of Maastricht and the Maasland Hospital, in Maastricht and Sittard, Netherlands, enrolled 45 patients on long-term omeprazole medication (mean, 35 months), and 13 control patients without medication, onto the study.
The researchers determined volatile N-nitrosamines in gastric juice and urine. Intragastric pH, nitrate, nitrite, and Helicobacter pylori status were also determined.
In addition, DNA isolated from gastric biopsy specimens was analyzed for precarcinogenic alkyl-DNA adducts.
The research team found intragastric pH in subjects on omeprazole medication to be significantly higher compared with controls. Gastric nitrite levels however were not significantly higher.
|Long-term omeprazole treatment does not raise intragastric nitrite and N-nitrosamines|
No differences in the levels of intragastric volatile N-nitrosamines were observed between patients and controls, although urinary N-nitrosodimethylamine excretion was significantly higher in the omeprazole group.
In omeprazole-medicated patients, those that were H. pylori-positive were found to have a non-significantly higher intragastric nitrite level, and higher urinary N-nitrosodimethylamine excretion, when compared to H. pylori-negative patients.
No alkyl-DNA adducts could be detected in gastric epithelium.
The research team concludes that increased gastric pH caused by long-term treatment with omeprazole does not result in increased intragastric levels of nitrite and volatile N-nitrosamines.
They suggest that the significantly higher urinary N-nitrosamine excretion implies the risk of increased endogenous formation of N-nitrosamines during long-term omeprazole treatment and add that this risk may be higher in H. pylori-positive patients.