Effect of ranitidine on the urea breath test: a controlled trial

Because Helicobacter pylori is an acid-sensitive organism, an elevation of the gastric pH by H2 inhibitors might improve the intragastric conditions for the development of this organism. We tested this hypothesis in a prospective and controlled trial including 43 patients positive for H. pylori using the rapid urease test. Twenty-six patients received 150 mg ranitidine twice daily and 17 patients received no treatment. The 14C-urea breath test was performed in both groups at the beginning of the study and 2 weeks later. Radioactive 14C in exhaled carbon dioxide was significantly increased (p = 0.045) in the patients treated with ranitidine, compared with the patients in the control group. Administration of this drug to patients infected with H. pylori is associated with an increase in the bacterial load after 2 weeks of treatment. This phenomenon might be attributed to increased bacterial growth due to the H2 blocker.