Fluoxetine in functional constipation with somatic symptom disorder ‒ Efficacy and safety from a propensity...

functional constipation (FC) is often accompanied by somatic symptom disorder (SSD), especially in refractory conditions. In such patients, constipation manifestations often appear to reflect heightened somatic symptoms rather than bowel dysfunction such as excessive preoccupation to defecation. Therefore, we conducted a cohort study to evaluate the efficacy and safety of fluoxetine in patients with FC and comorbid SSD.

the cohort study involved 316 FC patients with somatic symptoms. Among them, 161 patients received fluoxetine, while 155 were treated with polyethylene glycol (PEG). Using propensity scores, patients were matched into 77 pairs for comparative analysis. The primary outcome was the proportion who achieved ≥ 3 completely spontaneous bowel movements (CSBMs) per week at six-months. Secondary outcomes included the assessment of bowel symptom, mental scale, and treatment satisfaction. Safety was evaluated by adverse events.

at six months, 40.26 % of the fluoxetine group achieved the primary endpoint compared to 22.08 % in the PEG group (p = 0.009). Significant improvements were noted in secondary outcomes, including frequency of CSBMs, bowel symptom severity, GAD-9 score, and patient satisfaction. Key factors contributing to treatment effectiveness included baseline GAD-9 scores > 9 (OR = 5.01; p < 0.01). Adverse events occurred in 16 cases (9.9 %) of the fluoxetine group, with most being mild life-affecting.

fluoxetine appears to be a safe and effective therapeutic option over a six-month period for patients with FC and SSD, exerting dual benefits in alleviating both constipation and associated psychological symptoms.