Objective: To compare gastric pH control using intravenous famotidine as a primed, continuous infusion versus intermittent infusion.
Methods: In a prospective, double-blind study, 40 ICU patients at risk for stress ulceration were randomly assigned to receive either famotidine 20 mg intravenous bolus followed by 1.67 mg/h infusion or famotidine 20 mg intravenously every 12 h. Intraluminal gastric pH was recorded at baseline and every 4 h using a glass electrode. Clinical outcome indicators were also monitored. Subjects were studied for a minimum of 24 h and a maximum of 6 days. Continuous variables were analyzed by ANOVA and nominal variables by Fisher's exact test (alpha = 0.05).
Results: Nineteen patients were randomized to the continuous infusion group, and 21 were randomized to the intermittent group. Using gastric pH greater than 4.0 as an endpoint, the continuous group exhibited better pH control, both in terms of percentage of total measurements (83% versus 63%, p < 0.001) and time spent above pH 4.0 (91% versus 76%, p < 0.01). Similar results were found at pH greater than 5.0 (78% versus 56% for all measurements for the continuous and bolus groups, respectively (p < 0.001), and 88% versus 72% for the time spent above pH 5.0 (p < 0.01). Clinical outcomes, including evidence for gastrointestinal bleeding and hospital mortality, did not differ significantly between groups.
Conclusion: Famotidine infusion at 1.67 mg/h, when preceded by a bolus dose of 20 mg, provides a greater and more sustained increase in gastric pH than intermittent administration of famotidine 20 mg every 12 h.