IBS Treatment Updated

Summarized by Robert W. Griffith, MD
June 14, 2007

Summary

The British Society of Gastroenterology has issued guidelines for diagnosing and treating irritable bowel syndrome (IBS). Here's a digest of the main recommendations.

Introduction

New drugs introduced in the last 10 years for both types of irritable bowel syndrome (IBS) have run into side-effect problems. Tegaserod (Zelnorm^®), which is effective in constipation-type IBS, has recently been withdrawn in the USA, at the request of the FDA: the authorities were concerned about a slight increase in the number of heart attacks, strokes and severe cardiac chest pain (angina) in patients taking the drug, compared with those taking placebo. In 2000, alosetron (Lotronex^®) was withdrawn, after studies linked it to an increased risk of severe constipation and ischemic colitis; it has been re-introduced, with strong warnings about possible side effects.

A review of current thinking on treatment is clearly in order. The British Society of Gastroenterology has issued guidelines for diagnosing and treating IBS, which have been published in the medical journal Gut. Here's a digest of the main recommendations.

Diagnosis of IBS

IBS can be classified according to the predominant bowel habit - diarrhea or constipation. In the diarrhea type, few investigations are needed to make the diagnosis; a careful history will usually suffice (abdominal pain relieved by defecation, looser stool, and change in frequency). Patients who have IBS with constipation can have sensitive intestines that are far less tolerant, leading to pain and a great deal of discomfort from even minor constipation. Self-treatment may cause diarrhea, causing confusion about the type of IBS, so that here, too, a careful history is important.

Features that may help the diagnosis include frequent doctor visits for medically unexplained symptoms and a history of anxiety or depression. Somatization - the conversion of anxiety into physical symptoms - is common with IBS.

Certain symptoms are called "alarm symptoms" and warrant further investigation, such as a full white blood cell count, an erythrocyte sedimentation rate, and celiac serology to exclude celiac disease. They include:

• Age over 50
• Symptom duration less than 6 months
• Male sex
• Weight loss
• Symptoms at night
• Family history of colon cancer
• Rectal bleeding
• Anemia
• Recent antibiotic use

After the diagnosis (definite or tentative) has been conveyed, the patient should be given the opportunity to discuss their fears; for instance, the belief that their symptoms reflect more serious disease.

Treatment

Because IBS is such a diverse disease, no single treatment benefits more than 20% of patients. This means the focus of management should be to target specific treatments to those who will benefit.

Dietary management should start with a detailed dietary history, followed by moderation of excessive consumption of any one component. For instance, if lactose, wheat, and/or insoluble fiber intake seems to be above average, trial exclusion of one or all of these may be beneficial.

Psychological therapy should be in the forefront if anxiety, depression, or panic attacks are prominent features. Relaxation therapy, cognitive behavioral therapy¹ and psychodynamic interpersonal therapy² can all help some patients cope with their disease, and hypnotherapy has been shown to be effective in difficult cases.

Medications

In general, the effectiveness of drugs in IBS is somewhat disappointing, compared with their clear-cut benefits in other diseases. The following medications have shown greater benefits than placebo for different symptoms:

Pain is improved by antispasmodics, such as such as dicyclomine (Bentyl^®), hyoscyamine (Levsin^®), and belladonna/phenobarbital (Donnatal^®).

Constipation-predominant IBS can be improved by taking soluble fiber supplements (e.g. Metamucil^®), but bran and insoluble fiber may worsen symptoms. Drugs of the 5HT-4 agonist class³ improve constipation and bloating, but the withdrawal of tegaserod (Zelnorm) sets a high hurdle for developers of new candidates, as the increase in side effects was so small that impossibly large clinical trials would be required.

Diarrhea-predominant IBS responds to 5HT-3 antagonists, but here again rare side effects (e.g. colitis) with alosetron (Lotronex) casts a shadow on this class of drugs for use in IBS. Loperamide (Imodium^®) may reduce urgency of defecation and frequency, but increase discomfort and pain.

Tricyclic antidepressant drugs improve pain and help with psychological symptoms; selective serotonin inhibitors (SSRIs), which are also antidepressants, improve global symptoms in many cases.

Conclusions

IBS is a common disorder and has an important negative impact on quality-of-life and social functioning in many patients. However, it is not known to be linked to the development of serious disease or to affect mortality.

Treatment is largely unsatisfactory, as there is no good way to determine which patients will respond to specific therapies. The British review concludes that more research is needed in this direction.

Source

• Spiller R, et al. Guidelines for the management of Irritable Bowel Syndrome. Gut.2007; 0: gut.2007.119446v1

Footnotes
1. Cognitive behavior therapy combines two very effective kinds of psychotherapy. Cognitive therapy shows you how certain thinking patterns are causing your symptoms, by giving you a distorted picture of what's going on, and making you anxious, depressed or angry. Behavior therapy helps you weaken the connections between troublesome situations and your habitual reactions to them, such as fear, depression, or anger.
2. Psychodynamic interpersonal therapy emphasizes the ways in which a person's current relationships and social context cause or maintain symptoms, rather than exploring the deep-seated sources of the symptoms. Its goals are rapid symptom reduction and improved social adjustment.
3. Serotonin or 5-hydroxytryptamine (5-HT), acting particularly through the 5-HT3 and 5-HT4 receptors, plays a significant role in the control of gastrointestinal motility, sensation and secretion.

Related Links
Treating IBS by Hypnosis?
Yogurt's Effects on Intestinal Conditions
A Psychologist has Irritable Bowel Syndrome - Part 1: Understanding the Problem

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.