Influence of anti-ulcer drugs used in Japan on the result of 13C-urea breath test for the diagnosis of Helicobacter pylori infection

Background. The C-13-urea breath test (UBT) is a simple test for the diagnosis of Helicobacter pylori infection, but several factors have been reported to affect the results of this test. In this study, the effects of the anti-ulcer drugs used in Japan on the results of the UBT were determined. Methods. The subjects of the study were 64 adult volunteers who tested positive for H. pylori infection by the serum antibody method. Eight classes of anti-ulcer drugs used in Japan were administered at their usual doses to these subjects: lansoprazole, a proton pump inhibitor (PPI); nizatidine, an H-2-receptor antagonist (H(2)RA); and polaprezinc, ecabet sodium, rebamipide, teprenone, cetraxate hydrochloride, and sucralfate, all mucoprotective agents. The study drugs were randomized for administration to the subjects, and each of the drugs was administered for 14 consecutive days. The UBT was performed on days 0, 14, and 21. Results. The mean Delta(13)Cparts per thousand in the lansoprazole group was significantly decreased on day 14, to below 10parts per thousand, in 4 of 16 subjects, and in 1 of the 4 subjects, the test result was negative, with the Delta(13)Cparts per thousand falling to 1.7parts per thousand. The value returned to baseline I week after the discontinuation of lansoprazole. The other drugs administered had no significant effect on the result of the UBT, except that the mean Delta(13)Cparts per thousand showed a tendency to decrease after the administration of ecabet sodium and rebamipide. Conclusions. Administration of a PPI may produce a false-negative UBT result, while other anti-ulcer drugs, for the most part, have little effect on the result of the UBT when used alone.