Optimizing ear-based vagus nerve stimulation for hard-to-treat constipation
A Prospective, Randomized, Controlled Trial Investigating Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Intervention Strategies and Neurophysiological Mechanisms in Patients With Refractory Constipation
This trial will test whether gentle electrical stimulation of the ear (taVNS) twice daily for 20 days helps adults with refractory constipation have more complete spontaneous bowel movements and reduces laxative use.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 100 (estimated) |
| Sex | All |
| Sponsor | Xijing Hospital of Digestive Diseases Academic / other |
| Locations | 1 site (Xi'an) |
| Trial ID | NCT07344402 on ClinicalTrials.gov |
What this trial studies
This randomized, double-blind interventional study compares active transcutaneous auricular vagus nerve stimulation (taVNS) to a sham procedure in adults with refractory functional constipation. Participants are assigned to active or sham taVNS for 20 days, receiving two 30-minute sessions per day at 30 Hz and 200 μs pulse width delivered to the left cymba conchae. The main outcome is change in complete spontaneous bowel movements per week from baseline to post-treatment, with additional tracking of rescue laxative use and adverse events. Participants keep a daily bowel diary and safety and tolerability are monitored throughout the study.
Who should consider this trial
Good fit: Adults aged 18–80 who meet Rome IV criteria for functional constipation, have ≤2 complete spontaneous bowel movements per week during screening, and have had at least 3 months of prior therapy with inadequate response are the intended participants.
Not a fit: Patients whose constipation is explained by organic or secondary causes or who meet protocol exclusion criteria are unlikely to benefit from this taVNS approach.
Why it matters
Potential benefit: If successful, taVNS could provide a non-drug option that increases complete spontaneous bowel movements and reduces the need for rescue laxatives in adults with refractory constipation.
How similar studies have performed: Small pilot studies and animal data suggest vagus nerve stimulation can affect gut motility, but clinical evidence for taVNS in refractory constipation is limited and mixed.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria (Revised) Diagnosis of Functional Constipation (FC): Meets Rome IV criteria for functional constipation. Low CSBM frequency during screening: During the 2-week screening/run-in period, has ≤2 complete spontaneous bowel movements (CSBMs) per week, based on daily diary. Inadequate response to prior therapy: History of ≥3 months of prior constipation treatment (e.g., laxatives and/or prokinetic agents) with inadequate response (persistent constipation symptoms and/or persistently low CSBM frequency) as documented by medical history and/or records. Age: 18 to 80 years. Ability to comply: Able and willing to comply with study procedures (including stimulation sessions and diary completion). No concurrent clinical trial participation: Not participating in another interventional clinical trial during the study period. Informed consent: Provides written informed consent. Exclusion Criteria (Revised) Organic/secondary causes of constipation: Evidence or history of gastrointestinal organic disease (e.g., inflammatory bowel disease, colorectal tumor, congenital megacolon) or other conditions likely to cause secondary constipation, including endocrine/metabolic disorders (e.g., uncontrolled hypothyroidism, uncontrolled diabetes) or neurological disorders (e.g., Parkinson's disease, spinal cord disorders). Medications causing constipation (unless stable): Current use of medications known to cause constipation (e.g., opioids, anticholinergics) that cannot be discontinued or kept stable during the study, in the investigator's judgment. Opioid use disorder or chronic opioid use: History of substance abuse or chronic opioid use that may affect bowel function. Severe psychiatric conditions or safety risk: Current severe psychiatric disorder requiring urgent intervention, or risk of self-harm/suicide as assessed by a qualified clinician. Contraindications to taVNS or ear stimulation: Significant ear disease or skin lesions/infection at the stimulation site, or other contraindications to the study device/procedure. Implanted electronic medical devices: Presence of implanted electrical devices (e.g., pacemaker, implantable cardioverter-defibrillator) or other conditions where electrical stimulation is contraindicated. Pregnancy or lactation: Pregnant or breastfeeding women. Serious comorbidities that may interfere: Severe or unstable medical conditions that could interfere with participation or outcome assessment (e.g., significant cardiovascular disease/arrhythmia, coagulation disorders or regular anticoagulant therapy, severe hepatic/renal impairment, organ failure). Cognitive/communication impairment: Cognitive impairment, aphasia, or other conditions preventing valid consent or reliable diary completion. Investigator discretion: Any condition that, in the investigator's opinion, makes the participant unsuitable for the study.
Where this trial is running
Xi'an
- Xijing Hospital — Xi'an, China (Recruiting)
Study contacts
- Study coordinator: Zhifeng Zhao, Ph.D
- Email: zhaozhifeng@outlook.com
- Phone: +8613519171072
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.