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Assessment of intragastric urease activity by the 13C-urea breath test was performed before and after one day of dosing with either De-Noltabs (tripotassium dicitrato bismuthate, one tablet 1 q.d.s.), Pepto-Bismol liquid (bismuth salicylate 30 ml q.d.s.), or Roter tablets (bismuth subnitrate, one tablet q.d.s.) in twelve Helicobacter pylori-positive patient volunteers. There was a significant decrease in the excess of 13CO2 after one day of dosing with each of the three bismuth compounds, but analysis of variance could detect no difference between the effects of the three compounds. Systemic absorption of bismuth following oral dosing with either Pepto-Bismol or Roter is minimal, yet both compounds have a suppressive effect on H. pylori similar to that of De-Noltab. This study suggests that the action of all three bismuth compounds is within the gastric lumen, and that systemic absorption of bismuth is not necessary for activity against H. pylori.

Twelve healthy male subjects were dosed with six regimens: ranitidine and De-Noltab (tripotassium dicitrato bismuthate; Gist-Brocades Ltd., Weybridge, England), placebo and De-Noltab, ranitidine and Pepto-Bismol liquid [bismuth salicylate; Procter & Gamble (Health and Beauty Care) Ltd., Egham, England], placebo and Pepto-Bismol, ranitidine and Roter tablets (bismuth subnitrate; Roter Pharma Ltd., Ashford, England), and placebo and Roter. Ranitidine, 300 mg, or placebo was administered at 10 PM (night before) and at 7 AM; at 9 AM, the oral dose of bismuth was either 2 De-Noltabs, 3 30-mL doses of Pepto-Bismol liquid, or 2 Roter tablets. When predosed with placebo, the median integrated 8-hour plasma bismuth concentration was significantly greater after dosing with De-Noltabs than after dosing with either Pepto-Bismol or Roter (61, 8, and 8 ng.h/mL, respectively), with a similar trend for 8-hour median urinary bismuth excretion (213, 40, and 6 micrograms, respectively). When predosed with ranitidine, only after De-Noltab administration were there significant increases in the 8-hour plasma bismuth concentration (147 ng.h/mL), and 8-hour urinary bismuth excretion (686 micrograms). Eliminating intragastric acidity may enhance bismuth absorption after oral dosing with De-Noltabs by maintaining intragastric tripotassium dicitrato bismuthate as a colloidal suspension.