Intestine antisecretory agents

True antisecretory agents, those that block a biochemical process that promotes intestinal fluid secretion, are not available for clinical use in horses. Loperamide can reduce the volume of diarrhea in foals with a primarily small intestinal secretory disorder. However, treated foals may become colicky as a result of fluid distention in the intestines because the mechanism of action is primarily retention of fluid within the intestine. Also, retention of intestinal content may promote the proliferation of enteropathogens. The enkephalinase inhibitor racecadotril appears to have true antisecretory effect in animal models and in humans with diarrhea (Izzo et al 1998). Its safety or effectiveness in foals and horses has not been reported. 

Many types of bismuth mineral salts (e.g., bismuth subsalicylate) are generally multipurpose intestinal medicinal agents. As an antisecretory agent, bismuth subsalicylate coats and protects irritated and inflamed intestinal lumen tissue (antiulcer actions), decreases the secretion of fluid into the intestine, absorbs or neutralizes bacterial toxins, inhibits any bacterial activity (antidiarrhea actions), and also increases alkaline secretion to counteract any acid production (antacid action). Thus, this agent controls the frequent voluminous loss of watery stools while relieving intestinal cramping and irritation. 

Mechanism of Action An antinauseant and antiulcer agent that absorbs water and toxins in the large intestine and forms a protective coating in the intestinal mucosa. Also possesses antisecretory and antimicrobial effects. Therapeutic Effect Prevents diarrhea. Helps treat Helicobacter pybri-associated peptic ulcer disease. 

Loperamide Loperamide (imodium, imodium a-d, others), a piperidine butyramide derivative with -receptor activity, is an orally active antidiarrheal agent. The drug is 40-50 times more potent than morphine as an antidiarrheal agent and penetrates the CNS poorly. It increases small intestinal and mouth-to-cecum transit times. Loperamide also increases anal sphincter tone, an effect that may be of therapeutic value in some patients who suffer from anal incontinence. In addition, loperamide has antisecretory activity against cholera toxin and some forms of Escherichia coli toxin. 

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