NCT07850960Not yet recruitingPhase 4
Effect of Omeprazole on Gut Microbiota in Adults With Obesity and GERD
Effect of Proton Pump Inhibitors on Gut Microbiota Composition in Adults With Obesity and Gastroesophageal Reflux Disease
Source: ClinicalTrials.gov · Last updated 1 Oct 2026
Brief summary (registry, in English)
This randomized, open-label, parallel-group study will evaluate the effect of short-term omeprazole therapy on gut and oral microbiota in adults aged 50-65 years with obesity and symptomatic gastroesophageal reflux disease. Participants will be randomized 1:1 to receive omeprazole 20 mg once daily for 14 days plus standard non-pharmacological recommendations for gastroesophageal reflux disease, or standard non-pharmacological recommendations alone. Clinical and laboratory assessments will be performed at baseline and after 14 days. Stool and saliva samples will be collected to assess gut and oral microbiota, and blood samples will be collected for laboratory biomarkers.
- Status (registry)
- Not yet recruiting
- Phase (registry)
- Phase 4
- Study type
- Interventional
- Enrollment
- 26 (estimated)
- First submitted
- 24 Sept 2026
- Start date
- 25 Sept 2026
- Primary completion date
- 25 Dec 2026
- Lead sponsor
- Federal State Budgetary Scientific Institution
- Diseases
- Obesity
- NCT number
- NCT07850960
What you commit to
- Study type: Interventional · Phase 4
- Planned participants: 26
- From 25 Sept 2026 to the primary completion date, 25 Dec 2026
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Severe or exacerbated GERD, or GERD requiring acid-suppressive therapy or additional diagnostic evaluation.
- Use of proton pump inhibitors or histamine H2-receptor antagonists within 8 weeks prior to enrollment.
- Use of systemic antibiotics within 3 months prior to enrollment.
- Use of probiotic or synbiotic supplements within 8 weeks prior to enrollment.
Other illness
- Inflammatory bowel disease, celiac disease, or other severe chronic gastrointestinal disorders that may substantially affect the gut microbiota.
- History of bariatric surgery or other major gastrointestinal surgery.
- Acute infectious or inflammatory disease at enrollment.
- History of myocardial infarction or stroke.
- Type 2 diabetes mellitus.
- Chronic heart failure, New York Heart Association functional class III-IV.
- Chronic kidney disease with estimated glomerular filtration rate \<30 mL/min/1.73 m².
- Alcohol dependence or other substance use disorder.
- Severe psychiatric disorder or cognitive impairment that may interfere with providing informed consent or adherence to the study protocol.
- Known hypersensitivity or contraindications to omeprazole.
Who the study is looking for
- Age 50 to 65 years, inclusive.
- Obesity, defined as body mass index (BMI) ≥30 kg/m².
- Symptomatic gastroesophageal reflux disease with mild or moderate typical symptoms, including heartburn and/or regurgitation.
- For female participants, postmenopausal status, defined as absence of menstruation for at least 12 months without another apparent cause of amenorrhea.
- Written informed consent to participate in the study.
Age in the registry: 50 years to 65 years · Sex: All · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Federal Research Centre of Nutrition, Biotechnology and Food Safety Coordinator of this site? Confirm its status | Moscow | Russia | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.