SSRIs and Constipation

Mechanism and Effects

• SSRIs generally increase gastrointestinal motility through increased serotonin concentration at nerve endings, which would theoretically prevent rather than cause constipation 1

Clinical Guidelines and Recommendations

• The American Gastroenterological Association guidelines note that TCAs cause constipation as an adverse effect due to their anticholinergic properties, but this is not mentioned as a concern with SSRIs 2, 3
• When treating IBS-C patients, secondary amine TCAs are preferred over tertiary amine TCAs due to lower anticholinergic effects, but SSRIs are not recommended at all for IBS regardless of subtype 3