Antidepressants in the treatment of irritable bowel syndrome and visceral pain syndromes

Irritable bowel syndrome (IBS) is characterized by abdominal pain associated with disordered defecation, which may include urgency and altered stool frequency. Visceral pain syndromes, including IBS, may be effectively treated by a variety of therapies that modulate the interactions between the central and enteric nervous systems. Clinical observations and preliminary data suggest that antidepressants may be efficacious for the treatment of these syndromes. The tricyclic antidepressants (TCAs) have been utilized most extensively in this area, but there is a need for more rigorous efficacy data. Serotonin, an important neurotransmitter in both the central and enteric nervous systems, modifies both motility and sensation in the gut. Recognition of the importance of serotonin in digestive motility and sensation has sparked interest in the use of agents that modify serotonergic transmission in visceral pain syndromes. Pharmacological therapeutics that modulate the biological amines (serotonin, norepinephrine, dopamine and catecholamines) both peripherally and within the central nervous system may offer more effective therapies for these disorders. The selective serotonin reuptake inhibitors are commonly used in clinical practice, but more rigorous, controlled studies are needed to determine their effects beyond the treatment of psychiatric co-morbidity. The newer generation antidepressants may provide additional insight into the pathophysiology of the brain-gut interactions and their relationship to functional bowel disorders, providing new therapeutic interventions.