Cyclic Gastrointestinal Symptoms Induced by Selective Serotonin Reuptake Inhibitors: A Case Report of Menstruation-related Adverse Effects.

BACKGROUND

Gastrointestinal adverse effects are common with selective serotonin reuptake inhibitors (SSRIs), yet menstruation‑specific cyclic gastrointestinal symptoms have not been described.

OBJECTIVE

This report describes, to the best of our knowledge, the first documented case of menstruation-specific exacerbation of cyclic gastrointestinal symptoms associated with SSRI treatment and proposes a pragmatic management approach.

CASE SUMMARY: A 20‑year‑old woman with generalized anxiety disorder developed nausea, vomiting, diarrhea, and dizziness limited to menstrual periods after initiating escitalopram 10 mg/d; gastrointestinal symptoms persisted following a switch to paroxetine 20 mg/d. A comprehensive gynecologic work‑up (pelvic examination, hormonal assessment, and ultrasonography) was unremarkable. The Naranjo Adverse Drug Reaction Probability Scale scored 7, indicating a "probable" menstruation-specific adverse reaction. Reducing paroxetine to 10 mg/d resolved gastrointestinal symptoms, but anxiety symptoms recurred; titration to 15 mg/d achieved psychiatric remission without gastrointestinal symptom recurrence. After 6 months of stability, paroxetine was tapered off without recurrence of either gastrointestinal or anxiety symptoms.

KEY FINDINGS: This case demonstrates a menstruation‑modulated SSRI adverse effect mediated by a possible interaction between serotonergic signaling and cyclical sex steroid fluctuations.

IMPLICATIONS: An interdisciplinary, stepwise strategy (ruling out gynecologic disease, considering dose optimization, and monitoring menstruation‑linked symptoms) may help balance efficacy with tolerability in reproductive‑age patients. Prospective studies should evaluate SSRI-hormone interactions and menstrual-aware adverse effect monitoring.