Effects of Pharmacological Agents on Nonelectrolyte Nutrients and Ion Transport in Secretory Diarrhea

The present-day concepts on the pathophysiology of secretory diarrhea (1) have opened a new stage in the pharmacological treatment of diarrhea in children. Drugs used in the past as antidiarrheal agents and believed to act only on intestinal motility are now being viewed as antisecretory compounds, and their antidiarrheal action is being attributed, at least partially, to their action on the fluxes of ions and water in the intestine. Other compounds potentially useful as antidiarrheal agents because of their intestinal antisecretory effect are appearing on the scene. Powell and Field (2) have recently reviewed the pharmacological approaches to treatment of secretory diarrhea and they have discussed the possible mechanisms of action of currently used antidiarrheal agents as well as of newer, potentially useful drugs. The reader is referred to this excellent review for numbers, types, and possible mechanisms of action of antidiarrheal drugs. Antidiarrheal agents can be grouped into two main classes. One class appears simply to enhance the normal absorptive processes, offsetting the secretion produced by diarrheagenic agents: the oral glucose-electrolyte solution and adrenal corticoids are among the best-known examples. Compounds in the other category predominantly seem to turn off intestinal secretory mechanisms. The long list of compounds in this group includes the following: