Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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NOT_YET_RECRUITING
PHASE2
225 participants
INTERVENTIONAL
2025-12-15
2027-01-01
Brief Summary
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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.
Detailed Description
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Conditions
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Keywords
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Study Design
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RANDOMIZED
PARALLEL
TREATMENT
QUADRUPLE
Study Groups
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low dose for IBS-D
RNIB21 containing rifaximin 66mg + NAC 560mg three times a day
rifaximin 66mg + N-acetylcysteine 560mg three times daily
RNIB21 containing rifaximin 66mg + N-acetylcysteine 560mg three times daily
high dose for IBS-D
RNIB21 containing rifaximin 132mg + NAC 560mg three times a day
RNIB21 containing rifaximin 132mg + N-acetylcysteine 560mg three times daily
RNIB21 containing rifaximin 132mg + N-acetylcysteine 560mg three times daily
placebo
placebo three times a day
Placebo
placebo three times daily
Interventions
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rifaximin 66mg + N-acetylcysteine 560mg three times daily
RNIB21 containing rifaximin 66mg + N-acetylcysteine 560mg three times daily
RNIB21 containing rifaximin 132mg + N-acetylcysteine 560mg three times daily
RNIB21 containing rifaximin 132mg + N-acetylcysteine 560mg three times daily
Placebo
placebo three times daily
Eligibility Criteria
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Inclusion Criteria
2. Diagnosed with IBS confirmed by the Rome IV criteria, with associated symptoms of diarrhea as noted below in 4(b).
3. Do not have adequate relief of IBS symptoms of abdominal pain, stool consistency or stool frequency
4. Have daily IBS symptom scores during screening as below:
1. Weekly average score of worst daily abdominal pain \>3.0 on a 0-10 point scale
2. At least one stool with a consistency of Type 6 or 7 on the Bristol
Exclusion Criteria
1. Less than 3 bowel movements a week,
2. Hard or lumpy stools, and
3. Excessive straining during a bowel movement.
2. History of inflammatory bowel disease, celiac disease, GI surgery (except cholecystectomy and/or appendectomy)
3. Evidence of active duodenal ulcer, gastric ulcer, diverticulitis, or active infectious gastroenteritis
4. Current diagnosis of asthma
5. Current user of NAC and/or rifaximin
6. Systemic antibiotic use in the last month
7. Not currently on a prokinetic drug
8. A significant medical condition including but not limited to hepatic, uncontrolled diabetes, renal, cardiovascular, pulmonary, uncontrolled thyroid disease. or psychiatric disease, which in the opinion of investigator precludes study participation
18 Years
ALL
No
Sponsors
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Mark Pimentel, MD
OTHER
Responsible Party
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Mark Pimentel, MD
staff physician II
Central Contacts
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References
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Pimentel M, Chow EJ, Lin HC. Normalization of lactulose breath testing correlates with symptom improvement in irritable bowel syndrome. a double-blind, randomized, placebo-controlled study. Am J Gastroenterol. 2003 Feb;98(2):412-9. doi: 10.1111/j.1572-0241.2003.07234.x.
Lauritano EC, Gabrielli M, Lupascu A, Santoliquido A, Nucera G, Scarpellini E, Vincenti F, Cammarota G, Flore R, Pola P, Gasbarrini G, Gasbarrini A. Rifaximin dose-finding study for the treatment of small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2005 Jul 1;22(1):31-5. doi: 10.1111/j.1365-2036.2005.02516.x.
Scarpellini E, Gabrielli M, Lauritano CE, Lupascu A, Merra G, Cammarota G, Cazzato IA, Gasbarrini G, Gasbarrini A. High dosage rifaximin for the treatment of small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2007 Apr 1;25(7):781-6. doi: 10.1111/j.1365-2036.2007.03259.x.
O'Brien PC. Procedures for comparing samples with multiple endpoints. Biometrics. 1984 Dec;40(4):1079-87.
Pimentel M, Park S, Mirocha J, Kane SV, Kong Y. The effect of a nonabsorbed oral antibiotic (rifaximin) on the symptoms of the irritable bowel syndrome: a randomized trial. Ann Intern Med. 2006 Oct 17;145(8):557-63. doi: 10.7326/0003-4819-145-8-200610170-00004.
Sharara AI, Aoun E, Abdul-Baki H, Mounzer R, Sidani S, Elhajj I. A randomized double-blind placebo-controlled trial of rifaximin in patients with abdominal bloating and flatulence. Am J Gastroenterol. 2006 Feb;101(2):326-33. doi: 10.1111/j.1572-0241.2006.00458.x.
Trespi E, Ferrieri A. Intestinal bacterial overgrowth during chronic pancreatitis. Curr Med Res Opin. 1999;15(1):47-52. doi: 10.1185/03007999909115173.
Di Stefano M, Malservisi S, Veneto G, Ferrieri A, Corazza GR. Rifaximin versus chlortetracycline in the short-term treatment of small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2000 May;14(5):551-6. doi: 10.1046/j.1365-2036.2000.00751.x.
Corazza GR, Ventrucci M, Strocchi A, Sorge M, Pranzo L, Pezzilli R, Gasbarrini G. Treatment of small intestine bacterial overgrowth with rifaximin, a non-absorbable rifamycin. J Int Med Res. 1988 Jul-Aug;16(4):312-6. doi: 10.1177/030006058801600410.
Miglio F, Valpiani D, Rossellini SR, Ferrieri A. Rifaximin, a non-absorbable rifamycin, for the treatment of hepatic encephalopathy. A double-blind, randomised trial. Curr Med Res Opin. 1997;13(10):593-601. doi: 10.1185/03007999709113333.
Gillis JC, Brogden RN. Rifaximin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic potential in conditions mediated by gastrointestinal bacteria. Drugs. 1995 Mar;49(3):467-84. doi: 10.2165/00003495-199549030-00009.
Attar A, Flourie B, Rambaud JC, Franchisseur C, Ruszniewski P, Bouhnik Y. Antibiotic efficacy in small intestinal bacterial overgrowth-related chronic diarrhea: a crossover, randomized trial. Gastroenterology. 1999 Oct;117(4):794-7. doi: 10.1016/s0016-5085(99)70336-7.
Nayak AK, Karnad DR, Abraham P, Mistry FP. Metronidazole relieves symptoms in irritable bowel syndrome: the confusion with so-called 'chronic amebiasis'. Indian J Gastroenterol. 1997 Oct;16(4):137-9.
Drossman DA, McKee DC, Sandler RS, Mitchell CM, Cramer EM, Lowman BC, Burger AL. Psychosocial factors in the irritable bowel syndrome. A multivariate study of patients and nonpatients with irritable bowel syndrome. Gastroenterology. 1988 Sep;95(3):701-8. doi: 10.1016/s0016-5085(88)80017-9.
Agreus L, Svardsudd K, Nyren O, Tibblin G. Irritable bowel syndrome and dyspepsia in the general population: overlap and lack of stability over time. Gastroenterology. 1995 Sep;109(3):671-80. doi: 10.1016/0016-5085(95)90373-9.
Hungin AP, Whorwell PJ, Tack J, Mearin F. The prevalence, patterns and impact of irritable bowel syndrome: an international survey of 40,000 subjects. Aliment Pharmacol Ther. 2003 Mar 1;17(5):643-50. doi: 10.1046/j.1365-2036.2003.01456.x.
El-Serag HB. Impact of irritable bowel syndrome: prevalence and effect on health-related quality of life. Rev Gastroenterol Disord. 2003;3 Suppl 2:S3-11.
Gwee KA, Wee S, Wong ML, Png DJ. The prevalence, symptom characteristics, and impact of irritable bowel syndrome in an asian urban community. Am J Gastroenterol. 2004 May;99(5):924-31. doi: 10.1111/j.1572-0241.2004.04161.x.
Ruben H. A universally applicable dental prop. Br Dent J. 1968 Jun 4;124(11):525-6. No abstract available.
Bommelaer G, Poynard T, Le Pen C, Gaudin AF, Maurel F, Priol G, Amouretti M, Frexinos J, Ruszniewski P, El Hasnaoui A. Prevalence of irritable bowel syndrome (IBS) and variability of diagnostic criteria. Gastroenterol Clin Biol. 2004 Jun-Jul;28(6-7 Pt 1):554-61. doi: 10.1016/s0399-8320(04)95011-7.
Pimentel M, Chow EJ, Lin HC. Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome. Am J Gastroenterol. 2000 Dec;95(12):3503-6. doi: 10.1111/j.1572-0241.2000.03368.x.
Related Links
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Read NW. Irritable Bowel Syndrome. In: Feldman J, Friedman LS, Sleisenger MH, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 7th ed. Philadelphia, PA: Saunders; 2002: 1794-1806.
Pimentel M. A New IBS Solution: Bacteria - The missing link in treating irritable bowel syndrome. Sherman Oaks, CA: Health Point Press; 2006.
Other Identifiers
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RNIB21-201
Identifier Type: -
Identifier Source: org_study_id