Assessment and Treatment of Constipation in Patients with IBS

Polyethylene glycol is safe, has been found to improve bowel function, and is relatively cheap, making it one of the most effective treatments for occasional constipation in patients with irritable bowel syndrome (IBS), said Anthony J. Lembo, MD, associate professor of medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston.

Lembo reviewed the current state of IBS diagnosis and treatment at “Clinical Practice Skills in a Changing World,” during a presentation at the 2014 American Gastroenterological Association Clinical Congress of Gastroenterology and Hepatology in Miami Beach, FL, on Jan 17.

Lembo said he uses polyethylene glycol along with fiber supplements in patients with constipation-predominant IBS. However, he said he tends to use the treatment with patients who do not have much abdominal pain, as polyethylene glycol has not been shown to be particularly effective for treating that symptom.

In addition to polyethylene glycol, other common treatments involved with IBS include antispasmodics, lubiprostone, and rifaximin, along with increased fiber intake and/or fiber supplements.

Lembo also mentioned several studies that have examined the use of probiotic Align, Activia yogurt, and alosetron hydrochloride to address IBS symptoms. “Alosetron hydrochloride is not used often, but the data are good for severe IBS,” he explained. Peppermint oil is another possible treatment for IBS, although it has been difficult to target an exact dosage, he said.

Tracking the Roots of IBS

IBS is more prevalent in Western Europe and in patients who are middle aged, Lembo said. Depression, migraine, and anxiety are common co-morbidities. IBS is usually caused by changes in diet, an illness, or stress. Moderate and advanced cases are associated with quality of life impairment, more work-related absenteeism, and the possible need for consultation with a psychiatrist or psychologist to help manage anxiety or depression.

Clinicians should be on the lookout for “alarm features” of IBS, including onset in a patient who is age 50 or older and has gastrointestinal bleeding or nocturnal diarrhea. “IBS patients without alarm features are infrequently found to have organic disease,” Lembo said.

Gastroenterologists should coach patients with mild IBS to consider lifestyle changes and reassure them that they can manage their symptoms.

Diet can also play a role in controlling IBS symptoms, although studies have not conclusively shown just exactly how much diet can make a difference. However, a 2014 study in Gastroenterology from Halmos et al. reported that a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet improved IBS symptoms in 30 patients compared with controls who ate a typically Australian diet. The FODMAP patients had fewer gastrointestinal symptoms and greater stool consistency.

“This is the best study to date that shows a low FODMAP diet improves IBS symptoms,” he said.

Lembo also briefly addressed the role of gluten in IBS, stating that some studies have found evidence supporting the use of a gluten-free diet to help alleviate IBS symptoms.