Lymphocytic Microscopic Colitis Associated with Paroxetine: A Psychiatric Nursing Case Report

To describe a case of biopsy-confirmed lymphocytic microscopic colitis (MC) temporally associated with paroxetine (Paxil) therapy and to highlight psychiatric nursing implications for monitoring serotonergic adverse effects across the brain-gut interface.

This case report was developed using clinical history, diagnostic findings, treatment course, and relevant literature on selective serotonin reuptake inhibitors, MC, and serotonergic signaling in gastrointestinal function.

A 27-year-old male with generalized anxiety disorder, panic disorder, agoraphobia, and irritable bowel syndrome developed chronic watery diarrhea, abdominal pain, bowel urgency, and one episode of fecal incontinence while receiving paroxetine, which had previously produced sustained psychiatric remission. Differential considerations included an irritable bowel syndrome flare, infectious diarrhea, inflammatory bowel disease, medication-associated diarrhea, and medication-associated microscopic colitis. Colonoscopy with biopsy confirmed lymphocytic MC. Paroxetine was discontinued, and the patient was treated with budesonide (Entocort EC) and adjunctive gastrointestinal therapies, leading to resolution of gastrointestinal symptoms. After recurrence of anxiety and panic symptoms and poor tolerability or inadequate response to alternative psychotropic medications, paroxetine extended-release was cautiously reintroduced with interdisciplinary monitoring. Gastrointestinal symptoms did not recur during the 1-year follow-up period.

This case illustrates the importance of psychiatric nursing vigilance for persistent gastrointestinal symptoms in patients receiving serotonergic antidepressants. Recognition of possible medication-associated MC may support timely referral, interdisciplinary collaboration, and individualized psychopharmacologic decision-making.