Rifaximin 200 mg Plus Oral Rehydration vs Oral Rehydration Alone in Children With Acute Diarrhea

August 12, 2026 updated by: Bausch Health Americas, Inc.

A Randomized, Open-Label Study to Assess Pharmacokinetics of Xifaxan® 200 mg in Pediatric Subjects 6 to 11 Years of Age With Acute Diarrhea of Suspected Bacterial Etiology, and the Safety and Efficacy of Xifaxan® 200 mg Plus Oral Rehydration Therapy (ORT) Compared to ORT Alone

The goal of this clinical trial is to learn how rifaximin 200 mg is processed in the body (pharmacokinetics) in children 6 to 11 years old with acute diarrhea that may be caused by bacteria. It will also learn about the safety and effectiveness of rifaximin when given with oral rehydration therapy (ORT) compared with ORT alone. The main questions it aims to answer are:

How does rifaximin 200 mg move through and leave the body in children with acute diarrhea?

Is rifaximin safe for children in this age group?

Does rifaximin plus ORT help resolve diarrhea faster than ORT alone?

Researchers will compare rifaximin plus ORT to ORT alone to see if adding rifaximin improves outcomes.

Participants will:

Take one rifaximin 200 mg tablet + ORT three times a day for 3 days or receive ORT alone

Receive oral rehydration therapy according to the investigator's standard of care

Attend up to 4 clinic visits over 5 days and receive 4 follow-up phone calls

Provide blood samples on Day 1 and Day 3 for pharmacokinetic testing (rifaximin group only)

Provide stool samples to identify bacterial pathogens

Keep a diary of stool frequency and consistency to help determine when diarrhea resolves

Be monitored for side effects, vital signs, and laboratory changes

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a randomized, open-label study to assess the pharmacokinetics of Xifaxan® 200 mg in pediatric participants 6 to 11 years of age with acute diarrhea of suspected bacterial etiology, and safety and efficacy Xifaxan® 200 mg plus ORT compared to ORT alone.

Participants will receive Xifaxan® 200mg (1 tablet) TID plus oral rehydration therapy (ORT) or ORT alone as per the Investigator's Standard of Care (SOC) for administering ORS for three days.

Participants will complete 3 or 4 study visits during the study; Screening (Day -2 to Day 1), Day 1, Day 3 (End of Treatment), and Day 5 (Last Clinic Visit), and 2 safety follow-up phone calls; Once during Day 6 to 8, and on Day 30 (End of Study). Participants may complete both Screening and Day 1 on the same day. At the Screening visit, participants will provide a stool sample for PCR testing to identify the bacterial pathogen isolated. During the 5-day study period, the participant or their caregiver will complete a diary to record the dose, the time of dosing, time and consistency of stools, and incidence of symptoms as defined above. In addition, the participant or the caregiver will record any AEs in the eDiary from Day 4 to Day 30 with Day 1 to Day 3 assessed during study visits.

Participants in the Xifaxan® 200 mg plus ORT arm will undergo two 6 to 8-hour pharmacokinetic sampling periods, the first following the first dose on Day 1 and the second following the first dose on Day 3. During these sampling periods, 3 blood samples (approximately 4 mL each) will be collected for analysis of rifaximin and 25- desacetyl rifaximin plasma concentrations at the following times: pre-dose, 1 hour (+/- 10 minutes) and no less than 6 but no more than 8 hours following the first dose of the day.

Study Type

Interventional

Enrollment (Estimated)

54

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Maryanne Santilli

Study Locations

  • United States
    • California
      • Lynwood, California, United States, 90262
        • Recruiting
        • Alliance Research Institute
        • Principal Investigator:
          • James Saunders
        • Contact:
    • Florida
      • Hialeah, Florida, United States, 33012
        • Recruiting
        • Direct Helpers
        • Contact:
        • Principal Investigator:
          • Manuel Sanchez
      • Miami, Florida, United States, 33136
        • Recruiting
        • SouthCoast Research Center
        • Contact:
        • Principal Investigator:
          • Adonis Maiquez
      • Miami, Florida, United States, 33144
        • Recruiting
        • Oceane7 Medical & Research Center, Inc
        • Contact:
        • Principal Investigator:
          • Edgar Gonzalez, MD
    • Georgia
      • Union City, Georgia, United States, 30291
        • Recruiting
        • Rophe Adult & Pediatric Medicine
        • Principal Investigator:
          • Yvonne Smith
        • Contact:
    • Illinois
      • Island Lake, Illinois, United States, 60042
        • Recruiting
        • Innovative Clinical Research Center
        • Contact:
        • Principal Investigator:
          • Eberechukwu Ibe
    • Oregon
      • Gresham, Oregon, United States, 97030
        • Recruiting
        • Cyn3rgy Research Corporation
        • Contact:
        • Principal Investigator:
          • Frank Calgano
    • Texas
      • Prosper, Texas, United States, 75078
        • Recruiting
        • Little Stars Pediatrics / Tattva Trials
        • Contact:
        • Principal Investigator:
          • Pragadeeswari Dhanasekaran
      • Rosharon, Texas, United States, 77583
        • Recruiting
        • LinQ Research
        • Contact:
        • Principal Investigator:
          • Frederick Ogwara
    • Virginia
      • Richmond, Virginia, United States, 23233
        • Recruiting
        • Tekton Research
        • Contact:
        • Principal Investigator:
          • David Gosselin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

4.1 Inclusion Criteria

A participant will be eligible for inclusion in this study if all of the following criteria are met:

  1. Parent/legally authorized representative and participant, as applicable, have provided written informed consent/assent, are able to understand, and agree to comply with, all study procedures and requirements.
  2. Participant is between 6 to 11 years of age (inclusive)
  3. Participant weighs at least 15 kg (33 lbs) at Screening
  4. Participant is able to swallow pills

  5. Participant has diarrhea of suspected bacterial etiology defined by:

    1. At least 3 unformed stools in the last 24 hours prior to Screening
    2. Illness for less than 96 hours at Screening
    3. Clinical presentation consistent with acute infectious diarrhea of suspected bacterial etiology
  6. The participant agrees to use a highly effective method of contraception (if applicable) and to have urine pregnancy tests. Applies to females of childbearing potential (defined as postmenarche). Participants must practice at least 1 of the following medically acceptable methods of birth control throughout the study:

Applicable to:

All Post-Menarche Female Particpants:

  • Highly effective hormonal contraception methods such as oral, implantable, injectable, vaginal ring, or transdermal contraception for a minimum of 1 full cycle (based on the participant's usual menstrual cycle period) before study drug administration.
  • Total abstinence from sexual intercourse since the last menses before screening and agrees to total abstinence from screening until at least 30 days after last study drug administration.
  • Intrauterine device.

All Males Participants:

  • Condoms with spermicide.
  • Total abstinence from sexual intercourse from screening visit until at least 30 days after last study drug administration.

4.2 Exclusion Criteria

A participant will not be eligible for inclusion in this study if any of the following criteria are met:

  1. Participant has a history of chronic diarrhea (defined as loose or watery stools persisting for at last 4 consecutive weeks) within 12 months prior to onset of current acute illness.
  2. Participant is unable to eat or drink.
  3. Participant has clinical features suggestive of invasive or severe bacterial diarrhea requiring alternative therapy (e.g., frank blood in stool, mucoid diarrhea with systemic symptoms such as high fever, severe abdominal cramping or tenderness, or signs of sepsis).
  4. Participant has taken >2 doses of anti-diarrheal therapies in the 24 hours prior to randomization.
  5. Participant has taken any oral antimicrobial drug within 14 days of randomization.
  6. Participant has a clinically significant or unstable medical condition, in the opinion of the Investigator, (including, but not limited to, evidence of severe dehydration noted by tachycardia, abnormal blood pressure, or decreased skin turgor) at the Screening visit.
  7. Participant has a known hypersensitivity or allergy to Xifaxan®, rifampin, rifamycin-derived antibiotics, or any of the components of the rifaximin (Xifaxan®) formulations used in this study.
  8. Participant is pregnant or lactating or plans to become pregnant during the study.
  9. Participant has had a previous history of malignancy.
  10. Participant has a history of tuberculosis infection and/or has received treatment for tuberculosis infection.
  11. Participant has any concurrent illness, disability or circumstance that may affect the interpretation of clinical data, could cause noncompliance with treatment or visits or otherwise contraindicates participation in this study in the opinion of the Investigator.
  12. Participant has had significant blood loss within the 30 days prior to the Screening visit which prevents the collection of the blood volume required for this study.
  13. Participant has participated in an investigational drug or device study within the 30 days prior to randomization.
  14. Participant is an immediate household family member of study site personnel directly involved in the conduct of this study.
  15. Participant is taking a medication that is prohibited per Section 4.5 (Prohibited Therapy).

The following therapies are prohibited from Screening through Day 5:

  • Anti-diarrheal medications, including:

    • Anti-motility agents (eg, loperamide, diphenoxylate, codeine, and paregoric).
    • Absorbent agents (eg, cholestryramine).
    • Anti-secretory agents (eg, bismuth subsalicylate, octreotide, and vapreotide).
  • Probiotics
  • Any antimicrobial agents with an expected activity against enteric bacterial pathogens
  • A P-glycoprotein (P-gp) inhibitor
  • Warfarin

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Rifaximin 200 mg + ORT
rifaximin 200 mg tablets orally three times daily for 3 days plus oral rehydration therapy (ORT) administered per investigator standard of care
Other: Oral Rehydration Therapy (ORT)
Participants receive oral rehydration solution according to the investigator's standard of care. This is administered either alone (for the ORT-alone arm) or in combination with rifaximin (for the rifaximin + ORT arm). Participants or caregivers complete a daily diary documenting stool frequency, stool consistency, and related symptoms.
Drug: Rifaximin 200 mg Tablet
Participants receive rifaximin 200 mg tablets orally three times daily (TID) for 3 days in combination with oral rehydration therapy (ORT). Blood samples for pharmacokinetic analysis are collected on Day 1 and Day 3 at pre-dose, 1 hour post-dose, and 6 to 8 hours post-dose.
Active Comparator: ORT Alone
ORT administered per investigator standard of care without rifaximin.
Other: Oral Rehydration Therapy (ORT)
Participants receive oral rehydration solution according to the investigator's standard of care. This is administered either alone (for the ORT-alone arm) or in combination with rifaximin (for the rifaximin + ORT arm). Participants or caregivers complete a daily diary documenting stool frequency, stool consistency, and related symptoms.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Peak Plasma Concentration (Cmax) of Rifaximin
Time Frame: Days 1 and 3
Cmax levels following rifaximin 200 mg + ORT
Days 1 and 3
Time to Maximum Plasma Concentration (Tmax) of Rifaximin
Time Frame: Days 1 and 3
Tmax for rifaximin following rifaximin 200 mg + ORT
Days 1 and 3
Area Under the Plasma Concentration-Time Curve From Time 0 to Last Quantifiable Concentration (AUC0-last) for Rifaximin
Time Frame: Days 1 and 3
Area under the concentration-time curve to last measurable concentration
Days 1 and 3
Area Under the Plasma Concentration-Time Curve Over the Dosing Interval (AUC0-τ) for Rifaximin
Time Frame: Days 1 and 3
Area under the concentration-time curve over the dosing interval
Days 1 and 3
Proportion of participants with Clinical Cure
Time Frame: Up to Day 5 (End of Treatment)

Proportion of participants achieving clinical cure, defined as either:

  1. No unformed stools within a 48-hour period with no fever (with or without other clinical symptoms such as abdominal cramps or pain, excess gas/flatulence, nausea, vomiting, urgency, tenesmus); or
  2. No watery stools and no more than two soft stools within a 24-hour period with no fever and no other clinical symptoms except for mild excess gas/flatulence.
Up to Day 5 (End of Treatment)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to Last Unformed Stool (TLUS)
Time Frame: Up to Day 5 (End of Treatment)
Time in hours from the first dose of study treatment to the last unformed stool, after which clinical cure is declared, based on subject/caregiver diary entries.
Up to Day 5 (End of Treatment)
Incidence of Treatment-Emergent Adverse Events (AEs)
Time Frame: Day 1-30
Number and percentage of participants with AEs and SAEs
Day 1-30
Change From Baseline in Clinical Laboratory Parameters
Time Frame: Day 1-30
Changes in hematology, chemistry, and urinalysis values
Day 1-30
Change From Baseline in Vital Signs
Time Frame: Day 1-30
Change in temperature, blood pressure, and pulse
Day 1-30

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Detection of Bacterial Pathogens in stool samples
Time Frame: Screening (Day -2 to Day 1)
Identification of bacterial pathogen(s) isolated from stool samples of enrolled participants.
Screening (Day -2 to Day 1)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bausch Health Americas, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 11, 2026

Primary Completion (Estimated)

April 20, 2027

Study Completion (Estimated)

July 31, 2027

Study Registration Dates

First Submitted

December 2, 2025

First Submitted That Met QC Criteria

December 10, 2025

First Posted (Actual)

December 16, 2025

Study Record Updates

Last Update Posted (Actual)

August 13, 2026

Last Update Submitted That Met QC Criteria

August 12, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RFPK1991

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The sponsor does not intend to share individual participant-level data from this study. Summary results will be posted in accordance with applicable regulations.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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