Objectives: To compare the effects of intermittent intravenous administration and continuous intravenous infusion of famotidine on gastric pH in critically ill patients.
Design: A prospective, randomized, crossover study of continuous infusion and bolus administration of famotidine in critically ill patients.
Setting: A 14-bed medical intensive care unit (ICU) of a 500-bed county hospital.
Patients: Medical ICU patients requiring stress ulcer prophylaxis.
Interventions: Patients were randomized to receive an equivalent dose of famotidine by continuous infusion or intravenous bolus for 24 hrs, and then were crossed over to the other arm of the study.
Measurements and main results: Critically ill patients who met the inclusion criteria were randomly assigned to receive famotidine 20 mg i.v. over 10 mins, every 12 hrs or a continuous infusion of 1.7 mg/hr for 24 hrs. After a 16-hr washout period, patients crossed over to the other arm of the study. Gastric pH was monitored continuously for 24 hrs. A total of 710 gastric pH measurements were obtained for each phase of the study. The mean area under the pH-time curve for a 24-hr period was higher for continuous infusion than bolus administration (p = .05). Continuous infusion of famotidine maintained a gastric pH of > or = 4 over a longer time period than bolus administration (20.8 hrs vs. 12.6 hrs, respectively; p < .01). Onset of therapeutic gastric pH for continuous infusion was slightly delayed as compared with bolus administration.
Conclusions: Continuous infusion of famotidine is more effective than an equivalent dose given by intermittent bolus in maintaining the appropriate gastric pH necessary for prevention of stress ulceration. Delayed onset of effect may warrant a priming dose when famotidine is given by continuous infusion.