Dicyclomine Hydrochloride

The goal of this clinical trial is to characterize regional intestinal fermentation physiology and determine how the response to fermentable dietary fiber differs between healthy individuals and individuals with irritable bowel syndrome (IBS). The study will use ingestible capsule technologies to directly measure intestinal gases and regional microbiome composition following low-fiber and high-fiber meal challenges. The main questions it aims to answer are: Does the change in regional intestinal gas levels following a fermentable-fiber challenge differ between participants with IBS and healthy controls? How are regional intestinal gas dynamics associated with microbiome composition, breath gases, serum short-chain fatty acids, glucose dynamics, metabolites, and gastrointestinal symptoms? Researchers will compare participants with IBS to healthy controls to determine whether intestinal fermentation responses to dietary fiber differ between these populations. Participants will: Complete two study visits approximately one week apart. At one visit, participants will receive a low-fiber control meal, and at the other visit, they will receive the same base meal containing 15 g of inulin. The order of the two meals will be assigned at random. Swallow an Atmo gas-sensing capsule to measure intestinal H2, CO2, and O2 and a CapScan capsule to collect regional intestinal fluid for microbiome analysis. Undergo serial blood and breath sampling and gastrointestinal symptom assessments during each 8-hour study visit. Complete stool and urine collections, dietary assessment, and continuous glucose monitoring before and/or after the study visits.

While the pathophysiology of diarrhea-predominant irritable bowel syndrome (IBS-D) is complex and heterogeneous, dysbiosis of the gut microbiome is frequently observed, suggesting that a substantial subset of patients with irritable bowel syndrome (IBS) have symptoms that are initiated and/or perpetuated by a microbiome dysfunction. Successful randomized controlled trials (RCT) for IBS-D (Ford 2018; Black 2022) leveraging microbiome-targeted therapies (antibiotics or low microbiome fermentation diets) suggest the gut microbiome is at least partially involved in IBS symptoms. Furthermore, fecal microbiota transplantation (FMT) for patients with IBS-D has demonstrated promising results (El-Salhy 2020), supporting the possibility that altering the microbiome composition could ameliorate IBS-D symptoms. MITI-001 is a transplantable gut bacterial community composed of 157 live bacterial strains, encompassing 79 genera of commensal bacteria, that have been isolated from healthy donor stool, purified, and banked. The hypothesis of the proposed research is that MITI-001 can target the pathophysiologic lesion in a subset of IBS-D patients, restore the altered microbial metabolic process, and thus alleviate IBS-D symptoms.

This study will serve as a pilot randomized controlled trial to assess the feasibility of Psilocybin-Assisted Psychotherapy (PAP) in Treating Irritable Bowel Syndrome (IBS). Patients with severe IBS will undergo 3 pre-psychotherapy sessions with two licensed and trained psychedelic therapists, then will be randomized to undergo a guided psychotherapy session with single 25 mg oral "high" dose of psilocybin or a single 100 mg dose of niacin (active placebo) and attend 4 post-therapy integration sessions.

The purpose of this study is to examine the effectiveness of using a combination of a drug, rifaximin and a dietary supplement, N-acetyl-L-cysteine (NAC), to treat patients with irritable bowel syndrome with diarrhea (IBS-D). Rifaximin is one of the standard treatments for IBS-D and is FDA approved. While rifaximin is safe and effective for treating symptoms in patients with IBS-D, many patients find that their symptoms may not completely resolve, or may come back after a period of time. This research study is designed to test the investigational use of a combination of rifaximin and NAC. The combination of rifaximin and NAC is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of IBS-D, and the effects of taking both medications together are unknown. However, the two medications are approved for use separately, as detailed below. Rifaximin is the only antibiotic approved by the FDA for the treatment of IBS-D. Rifaximin (at a dose of 550 mg by mouth three times daily for 14 days) is approved by the FDA for the treatment of IBS-D. Rifaximin (at a dose of 200 mg per mouth three times daily for 3 days) is FDA approved for the treatment of traveler's diarrhea. Rifaximin at a dose of 200 mg per mouth three times daily is not approved by the FDA for the treatment of IBS-D. NAC is approved by the FDA to treat acetaminophen overdose (72-hour oral and 21-hour intravenous (IV) regimens), and for use in breaking up mucus in the lungs in patients with chronic obstructive pulmonary disease (COPD) and other lung conditions such as bronchitis. NAC is also available over-the-counter in 600 mg and 900 mg capsules as a dietary supplement, although over-the-counter use is not regulated by the FDA. This study will utilize the 600 mg dietary supplement capsules. The Investigators want to know if using a combination of rifaximin and NAC will give better results in decreasing IBS-D symptoms than using rifaximin alone. As NAC is used to break up mucus in the lungs, and the Investigators want to see if this can also break up the mucus layer in the small intestine, and therefore potentially increase the effectiveness of rifaximin. The Investigators will be testing 2 doses to determine which dose is most effective. participants are being asked to take part in this research study because participants were diagnosed with IBS-D.

A three month follow-up study to evaluate the effectiveness of a tailored anti-inflammatory eating plan guided by a registered dietitian to treat irritable bowel syndrome.