Which medications in the drug class Antidiarrheal agents are used in the treatment of Pediatric Irritable Bowel Syndrome (IBS)?

Updated: Dec 30, 2019
  • Author: Mohammad F El-Baba, MD; Chief Editor: Carmen Cuffari, MD  more...
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Answer

Antidiarrheal agents

These agents are used to treat diarrhea adjunctly with rehydration therapy to correct fluid and electrolyte depletion. They are usually helpful when diarrhea is the predominant symptom. Studies of the opiate agent loperamide show that it improves stool consistency, decreases stool frequency, and reduces abdominal pain. Cholestyramine acts by binding bile acids and can be helpful in some patients with irritable bowel syndrome. Alosetron and tegaserod are 5-HT4 receptor partial agonists that bind with high affinity at human 5-HT4 receptors. The activation of 5-HT4 receptors in the GI tract stimulates the peristaltic reflex and intestinal secretion and inhibits visceral sensitivity. In vivo studies showed that tegaserod enhanced basal motor activity and normalized impaired motility throughout the GI tract. In addition, studies demonstrated that tegaserod moderated visceral sensitivity during colorectal distention in animals.

Tegaserod was temporarily withdrawn from the US market in March 2007; however, as of July 27, 2007, restricted use of tegaserod is now permitted via a treatment IND protocol. The treatment IND allows tegaserod treatment of irritable bowel syndrome with constipation or chronic idiopathic constipation (CIC) in women younger than 55 years who meet specific guidelines. Its use is further restricted to those in critical need who have no known or preexisting heart disease.

Earlier this year, tegaserod marketing was suspended because of a meta-analysis of safety data pooled from 29 clinical trials that involved more than 18,000 patients. The results showed an excess number of serious cardiovascular adverse events, including angina, myocardial infarction, and stroke, in those taking tegaserod compared with placebo. In each study, patients were assigned at random to either tegaserod or placebo. Tegaserod was taken by 11,614 patients, and placebo was taken by 7,031 patients. The average age of patients in these studies was 43 years, and most patients (ie, 88%) were women. Serious and life-threatening cardiovascular adverse effects occurred in 13 patients (0.1%) treated with tegaserod; among these, 4 patients had a heart attack (1 died), 6 had unstable angina, and 3 had a stroke. Among the patients taking placebo, only 1 (0.01%) had symptoms suggesting the beginning of a stroke that went away without complication.

For more information, see the FDA MedWatch Product Safety Alert.

Loperamide (Imodium)

Synthetic opioid; does not have central nervous action in therapeutic doses. Acts by slowing intestinal motility and enhancing water and electrolyte absorption. Reduces diarrhea and pain in patients with diarrhea-predominant IBS.

Cholestyramine (Prevalite, Questran)

Binds endogenous bile acids and can improve diarrhea in patients with unexplained diarrhea or idiopathic bile acid malabsorption.

Alosetron (Lotronex)

Potent and selective antagonist of serotonin 5-HT3 receptor type. 5-HT3 receptors are extensively located on enteric neurons of GI tract, and stimulation causes hypersensitivity and hyperactivity of intestine. Alosetron blocks these receptors and, thus, is effective in controlling IBS symptoms.

Only approved for treatment in women with severe, chronic, diarrhea-predominant IBS that has failed to respond to conventional IBS therapy. Less than 5% of IBS is considered severe, and only a fraction of severe cases are diarrhea-predominant IBS. Limiting use to this severely affected population is intended to maximize the benefit-to-risk ratio. Previously removed from US market but reintroduced with new restrictions approved by FDA on June 7, 2002. Restricted because serious and unpredictable GI adverse events (some of which resulted in death) were reported in association with its use following original approval in February 2000.

Tegaserod hydrogen maleate (Zelnorm)

NOTE: As of April 2008, no longer available in US.

Previously available in US by restricted treatment IND for irritable bowel syndrome with constipation (IBS-C) or chronic idiopathic constipation (CIC) in women younger than 55 years who meet specific guidelines. Indicated for the short-term treatment of women with irritable bowel syndrome in which constipation is the predominant symptom. Serotonin type 4 receptor partial agonist with no affinity for 5-HT3 receptors. May trigger peristaltic reflex via 5-HT4 activation, which enhances basal motor activity and normalizes impaired GI motility. Research studies have shown inhibitory activity of drug on visceral activity in GI tract.


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