Clinical Research Directory
Browse clinical research sites, groups, and studies.
Evaluation of Fluoxetine for Refractory Constipation With Somatic Symptom Disorder Features
Sponsor: Zhifeng Zhao, PhD
Summary
This single-center, randomized, double-blind, placebo-controlled trial evaluates the efficacy and safety of fluoxetine (40 mg/day) versus placebo in 194 adults with refractory chronic constipation exhibiting Somatic Symptom Disorder (SSD) features diagnosed by SCID-5. After a 2-week screening period, participants are randomized 1:1 to fluoxetine or matching placebo for 12 weeks. The primary endpoint is the proportion of CSBM responders, defined as an increase of ≥1 CSBM per week from baseline in ≥50% of treatment weeks (Weeks 5-12). Key secondary endpoints include weekly SBM/CSBM frequency, Bristol Stool Form Scale, straining score, bloating severity, Patient Global Impression of Change (PGIC, 7-point), and changes in validated PRO scales (SSD-12, PHQ-15, PHQ-9, GAD-7, PAC-QOL, KESS). Mechanistic assessments include resting-state fMRI and high-resolution anorectal manometry (HRAM). Safety is monitored through adverse events, thyroid/liver/renal function tests, and ECG.
Official title: Randomized, Double-Blind, Placebo-Controlled, Single Center Trial to Evaluate the Efficacy and Safety of Fluoxetine in Patients With Refractory Constipation Exhibiting Somatic Symptom Disorder Features
Key Details
Gender
All
Age Range
18 Years - 70 Years
Study Type
INTERVENTIONAL
Enrollment
194
Start Date
2026-09-01
Completion Date
2027-09-30
Last Updated
2026-09-02
Healthy Volunteers
No
Interventions
Fluoxetine
Participants receive fluoxetine orally after breakfast, starting at 20 mg/day (1 capsule) for the first 7 days. From Day 8, the dose increases to the target of 40 mg/day (2 capsules), maintained through Week 12. If a participant cannot tolerate the 40 mg dose, the dose may be reduced back to 20 mg/day; if 20 mg remains intolerable, the study drug is discontinued and the participant enters safety follow-up. Rescue medications: For participants in both groups who have no bowel movement for 3 consecutive days or experience intolerable symptoms, a two-tier rescue protocol is available: (1) first line: polyethylene glycol 13.7 g orally; (2) second line: glycerin enema if no response to PEG after 24-48 hours. Rescue medication use must be recorded in the bowel movement diary and eCRF (date, time, dose). Rescue medications are distributed at each 4-week visit. Any bowel movement occurring within 24 hours after rescue medication use is classified as non-spontaneous (non-SBM) and excluded from
Placebo
Participants in the Placebo Control Group receive placebo tablets that are identical in appearance, taste, and packaging to the fluoxetine tablets. They take one placebo tablet orally once daily after breakfast for 12 weeks, following the same schedule as the treatment group to maintain blinding. Rescue medications: For participants in both groups who have no bowel movement for 3 consecutive days or experience intolerable symptoms, a two-tier rescue protocol is available: (1) first line: polyethylene glycol 13.7 g orally; (2) second line: glycerin enema if no response to PEG after 24-48 hours. Rescue medication use must be recorded in the bowel movement diary and eCRF (date, time, dose). Rescue medications are distributed at each 4-week visit. Any bowel movement occurring within 24 hours after rescue medication use is classified as non-spontaneous (non-SBM) and excluded from the CSBM/SBM endpoint calculation.