What Is the Role of Tricyclic Antidepressants in the Treatment of IBS?

Tricyclic antidepressants (TCAs), like the early antipsychotics, were developed from antihistamines with the aim to sedate disturbed psychiatric patients. They were first synthesized in the 1950s and derive their name from the three-amine ring structure that is common to this class of drugs. They have a variety of pharmacological actions, including serotonin and norepinephrine-reuptake inhibition as well as muscarinic, histaminic, and a1 adrenergic blockade. 1 TCAs have been shown to improve depressive symptoms in randomized controlled trials (RCTs), but the precise mechanisms by which they achieve this are unclear, which perhaps is not surprising given the diverse pharmacological actions of these drugs.