Irritable bowel syndrome (IBS) is an extremely common cause of consultation, and at present is diagnosed on the basis of symptoms and a few simple exclusion tests. Exclusion diets can be successful, but many patients have already attempted and failed such treatments before consulting. Anxiety and somatization may be an important driver of consultation. Patients' concerns should be understood and addressed. Those with prominent
psychiatric disease may benefit from psychotherapy.
Hypnotherapy benefits symptoms in those without psychologic disturbance, but its availability is limited.
Antidepressants are effective in improving both mood and IBS symptoms globally, and the evidence is particularly good for
tricyclic antidepressants. Although
antispasmodics are currently the most commonly prescribed drugs, most responses (75%) are due to the placebo effect and not specific to the
drug.
Bulk laxatives such as
ispaghula can increase stool frequency and help
pain, but bloating may be aggravated.
Loperamide is effective treatment for urgency and loose stools, but less effective for bloating and
pain. 5-HT(3) antagonists such as
alosetron improve urgency, stool consistency, and
pain in
diarrhea-predominant-IBS. The 5-HT(4) agonist
tegaserod shows modest benefit in
constipation-predominant IBS, improving stool frequency, consistency, and bloating as well as global improvement. There are many new drugs, such as
cholecystokinin, neurokinin, and
corticotropin receptor antagonists, in development.