Irritable bowel syndrome (IBS) is a common disorder which presents with abdominal pain or discomfort in association with altered bowel habit. IBS is further subcategorized as three types according to the predominant bowel movement pattern: IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), and mixed-IBS (IBS-M). The exact causes of IBS remain incompletely understood, but proposed mechanisms include abnormal motility, visceral hypersensitivity, abnormal brain-gut interactions, psychological distress, and altered GI tract motility. Lubiprostone, a novel drug that works by activating the colonic Chloride channel type 2(ClC-2), has been approved for use in patients with chronic idiopathic constipation and recently approved for the treatment of IBS-C in women aged 18 and older. By activating the ClC-2 chloride channel in the colon, lubiprostone allows more fluid secretion into the intestinal lumen which leads to softer stool consistency. In phase III clinical trials, patients with IBS-C receiving lubiprostone have reported improvements in many symptoms such as abdominal pain and constipation. However, there is limited physiologic data to explain how exactly lubiprostone improves IBS-C symptoms. The Smartpill is a novel non-digestible capsule that is capable of measuring intraluminal pH, pressure, and temperature in the gastrointestinal (GI) tract. Smartpill has been shown to accurately measure whole gut as well as regional (i.e. stomach, small bowel, colon) transit time. The primary aim of this study is to determine the effects of lubiprostone on whole GI tract transit, colonic transit, motility, and intraluminal pH in patients with IBS-C through evaluation with the Smartpill. The investigators propose to study the effect of lubiprostone vs. placebo on these parameters, and secondarily to evaluate changes in these parameters with differing doses of lubiprostone. The investigators hypothesize that lubiprostone will increase whole GI and colonic transit compared to placebo in patient with IBS. the investigators do not expect a change in intraluminal pH with lubiprostone compared to placebo.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
QUADRUPLE
Enrollment
60
lubiprostone taken either at a dose of 8 mcg orally twice daily (BID) for 28 days or 24 mcg orally once daily (QD) for 28 days
taken orally for 28 days
Ingestion of a small non-digestible capsule that measures temperature, pH and pressure of the immediate surrounds as it passes through the GI tract eventually exiting the body through the anus
University of Michigan Health System
Ann Arbor, Michigan, United States
Change in Gastric Emptying Time, Small Bowel Transit Time, Colon Transit Time and Whole Gut Transit Time From Baseline
Change in gastric emptying time, small bowel transit time, colon transit time and whole gut transit time measured in hours based on a measurement done at baseline and then again at 3 weeks into the intervention within each treatment arm
Time frame: 21-28 days
Change in Small Bowel pH and Colon pH From Baseline
Change in the mean pH of the small intestine and colon based on a measurement done at baseline and then again at 3 weeks into the intervention.
Time frame: 21-28 days
Change in Motility Pattern of the Small Bowel and Colon From Baseline as Defined by the Motility Index
Change in the motility index defined as the natural log \[(sum of pressure amplitudes times the number of contractions) + 1\] for the small bowel and colon based on a measurement done at baseline and then again at 3 weeks into the intervention.
Time frame: 21-28 days
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