Effects of pumaprazole (BY841), a novel reversible proton pump antagonist, and of omeprazole, on intragastric acidity before and after cure of Helicobacter pylori infection

Aliment Pharmacol Ther. 1999 Jan;13(1):27-34. doi: 10.1046/j.1365-2036.1999.00440.x.


Background: Omeprazole produces a higher intragastric pH in the presence of Helicobacter pylori infection than after cure.

Aim: To investigate whether this effect also occurs with pumaprazole (BY841), a reversible proton pump antagonist which, in contrast to omeprazole, does not require activation in the acid compartment of the parietal cell.

Methods: In a randomized, crossover, double-blind study, 24-h intragastric pH was measured in 13 H. pylori-positive subjects before and after a 1-week course of omeprazole (20 mg o.d.) or of pumaprazole (100 mg b.d.). The studies were repeated after the infection was cured.

Results: In the absence of drug administration, the median 24-h pH values before cure (median 2.0, 90% CI: 1.2-3.2) did not differ from those after cure (median 1.5, 90% CI: 1.3-2.2; P = 0.115). The 24-h pH values were higher before cure of the infection than after during both pumaprazole (6.0, 4.8-6.7 vs. 4.3, 2.6-5.7; P = 0.002) and omeprazole (5.8, 4.0-6.2 vs. 3.6, 2.8-5; P = 0.004). Both before and after cure, there were no significant differences between the two drugs with respect to acid inhibition over the 24-h period. The median decrease in acid inhibition after cure of the infection (calculated as the difference in H+ activity in mmol/L) during pumaprazole (median 0.05, 90% CI: 6 x 10-4- 2.3) was no different from that during omeprazole (median 0.2, 90% CI: 3 x 10-3-1.5; P = 0.6).

Conclusions: Both before and after cure of H. pylori infection, pumaprazole raised the intragastric pH over a 24-h period to a similar degree as omeprazole. H. pylori infection similarly augments the pH-increasing effect of both drugs. This effect is related to H. pylori infection and not to an increased activation of acid inhibitory agents in the parietal cell compartment.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antacids / pharmacology*
  • Anti-Ulcer Agents / pharmacology*
  • Cross-Over Studies
  • Double-Blind Method
  • Electrocardiography
  • Female
  • Gastric Acid / metabolism
  • Gastric Mucosa / metabolism
  • Gastrins / blood
  • Helicobacter Infections / drug therapy
  • Helicobacter Infections / physiopathology*
  • Helicobacter pylori* / isolation & purification
  • Humans
  • Hydrogen-Ion Concentration
  • Imidazoles / pharmacology*
  • Male
  • Omeprazole / pharmacology*
  • Proton Pump Inhibitors
  • Pyridines / pharmacology*
  • Stomach / chemistry
  • Stomach / drug effects*
  • Stomach / microbiology


  • Antacids
  • Anti-Ulcer Agents
  • BY 841
  • Gastrins
  • Imidazoles
  • Proton Pump Inhibitors
  • Pyridines
  • Omeprazole