Hydrogen (H2) Breath Excretion in Peptic Disease before and during Treatment with Ranitidine

Gastric juice pH, bacterial flora, and the H2 breath excretion were studied in patients treated with 150 mg ranitidine twice daily. The intragastric pH and bacterial contents rose during therapy. Before treatment upper respiratory tract bacteria were found in 4 of 23 patients and after 4 weeks of medication in 15 of 23. The median bacterial concentration was increased (p < 0.01) and in five patients included bacteria normally found in the colon. Prolonged therapy for up to 12 weeks (n = 8) did not further change the bacteriologic pattern. Prophylactic treatment for 1 year (n = 3) showed gastric bacteria in high concentration, including Pseudomonas, in one patient. Postprandial H, production remained unchanged after 4 (n = 23) and 12 (n = 7) weeks of therapy. In two of three patients treated prophylactically H2 excretion was increased after 1 year of medication. We conclude that acid reduction with ranitidine causes changes of the intragastric bacterial flora similar to those with other acid-reducing drugs...