The American Gastroenterological Association have published a new guideline on drugs for irritable bowel syndrome. The aim of the document is to make it easier for patients and their doctors to select the right drugs for the right symptoms.

Pharmacist with pills measuring out medication prescriptionShare on Pinterest
The AGA say their new guideline offers an evidence-based approach to help IBS patients and their doctors navigate the wealth of drug information.

Irritable bowel syndrome (IBS) is a disorder in how the gastrointestinal (GI) tract works; it is a cluster of symptoms rather than a disease. While IBS symptoms can occur frequently, they do not damage the GI tract.

The cause of IBS is unknown. Symptoms can include cramp, gassiness, bloating, changes in bowel habits, constipation and diarrhea. At times, IBS can make patients feel a need to move the bowels, but then they find they are unable to.

IBS does not lead to more serious diseases, such as cancer or inflammatory bowel disease. For most people, the symptoms are mild and annoying, but there are cases where they can be disabling.

According to the target="_blank" rel="noopener">American Gastroenterological Association (AGA), IBS affects up to 15% of the general adult population, and most patients struggle to achieve the correct drug therapy for their particular symptoms.

The AGA say their new guideline - published in the journal Gastroenterology - offers an evidence-based approach to help these patients and their doctors navigate the wealth of drug information.

Dr. Shahnaz Sultan - an assistant professor of medicine at the University of Florida College of Medicine and the Department of Veteran Affairs Medical Center of the North Florida/South Georgia Veterans Health System - comments on the new guideline that she co-authored:

"Because no IBS therapy is uniformly effective, many patients describe a history of a variety of treatments alone or in combination. This guideline will help patients and physicians navigate the drug options. It's also important to consider other clinically relevant information, such as a patient's values and preferences, when making treatment decisions."

In compiling the new guideline, Dr. Sultan and colleagues followed the Institute of Medicine's Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. This helped them sift through the large number of published IBS studies and pick out the ones in which the quality of data and balance between risks and benefits clearly supported the use of the particular drugs they examined.

Two classes of recommendation: strong and conditional

Using the GRADE system, the authors put the recommendations into two classes: strong recommendations and conditional (or weak) recommendations. These have different implications for patients, clinicians and policy makers, as follows:

Strong recommendations are those where patients would most likely not need formal help to decide whether the recommended course of action fits in with their values and preferences. Most patients would want the recommended course of action and only a small minority would not.

For clinicians, the implication of a strong recommendation is that most patients should receive the recommended treatment, and following the recommendation in line with the guidance could be used as a standard for assessing quality or performance. Most patients would be unlikely to need help in deciding whether the recommendation fits their values and preferences.

For policymakers, a strong recommendation means the recommendation can form the basis of policy in most situations.

Conditional (or weak) recommendations are those where most people would want the recommended course of action but many would not. Patients would most likely need formal decision aids to help them decide whether the recommended treatment is consistent with their values and preferences.

For clinicians, the implication of a conditional recommendation is that they will likely need to examine the evidence to help patients make up their minds as to whether the recommended course of action fits in with their values or preferences.

For policymakers, a conditional recommendation is one that requires considerable debate with stakeholders in order to formulate policy.

New recommendations by IBS type

For IBS with constipation (IBS-C)

For patients with IBS-C (constipation), the AGA guideline recommends linaclotide over no drug treatment, and it grades it as a strong recommendation supported by high-quality evidence.

The AGA suggest using lubiprostone over no drug treatment in patients with IBS-C, but they class this as a conditional recommendation based on moderate-quality evidence.

The AGA suggest using laxatives over no drug treatment in patients with IBS-C, but they class this as a conditional recommendation based on low-quality evidence.

For IBS with diarrhea (IBS-D)

For patients with IBS-D (diarrhea), the AGA guideline has no strong recommendations.

The guideline suggests using rifaximin over no drug treatment in patients with IBS-D, and it classes this as a conditional recommendation supported by moderate-quality evidence.

To improve global symptoms in patients with IBS-D, the guideline suggests using alosetron over no drug treatment and classes this as a conditional recommendation supported by moderate-quality evidence.

The guideline also suggests using loperamide over no drug treatment in patients with IBS-D, but it classes this as a conditional recommendation supported by very low-quality evidence.

The use of antidepressants and antispasmodics for IBS

The AGA guideline suggests using tricyclic antidepressants over no drug treatment in patients with IBS and classes this recommendation as conditional, supported by low-quality evidence.

The guideline recommends against using selective serotonin reuptake inhibitors for patients with IBS, and it classes this as a conditional recommendation supported by low-quality evidence.

The guideline suggests using antispasmodics (over no drug treatment) in patients with IBS, and classes this as a conditional recommendation supported by low-quality evidence.

The authors note that in most cases, in the wealth of literature they surveyed, they found the quality of the data and the balance of risks and benefits for a particular therapy did not overwhelmingly support the use of particular drugs.

They found no studies that compared the effectiveness of commonly used drugs, and neither did they find any studies that compared combinations of commonly used drugs.

Within the stated limitations, the AGA believe the new guideline represents a rigorous, evidence-based summary of the extensive literature on the use of drugs to treat IBS.

In March, Medical News Today learned of another report in the journal Gastroenterology, where an international team of researchers suggested there may be a genetic basis for some cases of IBS.