Use of continuous infusion of histamine2-receptor antagonists in critically ill patients

Certain clinical situations require the use of a histamine2 (H2)-receptor antagonist to reduce gastric-acid volume and concentration or an antacid to act as a buffering agent. Presently, there are three H2-receptor antagonists available for iv use: cimetidine, ranitidine, and famotidine. Conventional therapy dictates that the H2-receptor antagonist be given by intermittent intravenous infusion, resulting in peaks and valleys of acid secretory control. Antacids, although capable of providing adequate gastric acidity control, must be administered frequently, often hourly, and thus require excessive nursing time. Presented here is a review of the rationale for the use of an H2-receptor antagonist by continuous infusion.