Effects of intragastric pH increment by omeprazole on the eradication rate of Helicobacter pylori

Kim, Il Hoi; Kim, Hyun Soo; Lee, Dong Ki; Seo, Jeong In; Kim, Jae Woo; Baik, Soon Koo; Kwon, Sang Ok; Park, Joo Young; Uh, Young

Abstract

BACKGROUND: Although proton pump inhibitors (PPIs) combined with antibiotics have been known to increase the antimicrobial activity, the effect of PPIs on the eradication of Helicobacter pylori (H. pylori) is controversial. The aims of the present study were to evaluate the effect of omeprazole on the amoxicillin activity for the eradication of H. pylori using prospective double-blind clinical trial and to assess the inhibitory activity of amoxicillin on the H. pylori according to the pH in vitro.
METHODS
Thirty healthy volunteers with endoscopically proven H. pylori infection were randomized to either OA group (n=14); 2 weeks omeprazole (20 mg, b.i.d.) plus amoxicillin (750 mg, b.i.d.) or PA group (n=16); 2 weeks placebo plus the same antibiotic. The H. pylori status was assessed at baseline and at 6-week after the initiation of treatment, and the eradication rate of H. pylori was compared between two groups. Intragastirc pH and serum gastrin level were measured before and 1-week after the treatment also. In vitro, minimal inhibitory concentrations (MICs) of amoxicillin were assessed at the different pHs of media.
RESULTS
Intragastric pH significantly increased in OA group (p=0.02), however, did not change in PA group. The changes of intragastric pH parameters after 1-week treatment were significantly different between two groups (p<0.01). The eradication rates of H. pylori were 28.6% in OA group and 18.7% in PA group, and did not show a significant difference between two groups. In OA group, three intragastric pH parameters tended to be higher in the H. pylori eradication group than the non-eradication group, but the difference did not reach statistical significance. MIC of amoxicillin decreased with pH increment in vitro (r=-0.98, p=0.01).
CONCLUSION
Intragastric pH increment using omeprazole might increase the antibacterial activity of amoxicillin, however, did not affect the apparent improvement (>50%) in the eradication rate of H. pylori.