Antidepressant amitriptyline shown to alleviate symptoms of irritable bowel syndrome

May 1 2008

Researchers at Mattel Children's Hospital UCLA have found that low-dose antidepressant therapy can significantly improve the overall quality of life for adolescents suffering from irritable bowel syndrome (IBS).

The syndrome affects 6 percent of middle school students and 14 percent of high school kids in the United States.

The study, published in the May issue of the peer-reviewed Journal of Pediatrics, is the first of its kind to look at the effects of amitriptyline, a tricyclic antidepressant, in the pediatric IBS population, researchers said.

The research was conducted between 2002 and 2005 and involved 33 newly diagnosed IBS patients, including 24 girls, between the ages of 12 and 18.

Irritable bowel syndrome causes discomfort in the abdomen, along with diarrhea, constipation or both. Currently, there is no cure, and treatments only lessen the symptoms.

"While research has shown that amitriptyline is effective for adults with IBS, only peppermint oil has been studied in children with this disorder in a double-blind, placebo-controlled fashion," said Dr. Ron J. Bahar, assistant clinical professor of pediatric gastroenterology at Mattel Children's Hospital UCLA and lead author of the study. "Our results show that amitriptyline significantly improves overall quality-of-life measurements in adolescents and should be a therapeutic option for these patients. We were actually surprised to reach our conclusion with a relatively small number of subjects."

The 13-week study consisted of three phases: two weeks of enrollment and symptom scoring, eight weeks of therapy with amitriptyline or a placebo, and three weeks of post-medication "washout" and symptom scoring.

Patients were randomized in a double-blinded fashion to receive the antidepressant or a placebo and were surveyed at two, six, 10 and 13 weeks using a symptom checklist, a pain-rating scale, a pain intensity and frequency scale, and an IBS quality-of-life questionnaire.

The results showed that patients receiving amitriptyline were more likely to experience:

• An improvement in overall quality of life at six, 10 and 13 weeks.
• A reduction in IBS-associated diarrhea at six and 10 weeks.
• A reduction in pain near the belly button at 10 weeks.
• A reduction in pain in the right lower quadrant of the abdomen at six, 10 and 13 weeks.

Bahar said that more than half of eligible patients, or their parents or guardians, refused to enroll in the study because they were uncomfortable with using an antidepressant medication of any kind, citing negative reports in the media about their side effects and the Food and Drug Administration's formal 2004 "black box" warnings regarding the increased potential for suicide in children using antidepressants.

"However, the dose of AMI (amitriptyline) used in this study, as well as IBS treatment for adults, is far less than the dose to treat depression," Bahar said. "At these low levels, it could be considered a remedy to treat neuropathic pain associated with chronic pain symptoms, rather than an antidepressant or psychotropic medication."

The next stage of research will look at the long-term follow-up of these patients to determine who will continue to stay well on the medication, whose symptoms resolve spontaneously and what other medications can be used as an alternative to amitriptyline for adolescents with IBS.

The research was funded by James L. Brooks and the Diane Brooks Medical Research Foundation of the California Community Foundation, and by the pharmaceutical company AstraZeneca.

Other study authors included Dr. Brynie S. Collins, Dr. Barry Steinmetz and Dr. Marvin Ament.

Mattel Children's Hospital UCLA, one of the highest-rated children's hospitals in Southern California, is a vital component of UCLA Medical Center, which is ranked by U.S. News & World Report as the third best hospital in nation and best in the western United States. Mattel Children's Hospital offers a full spectrum of primary and specialized medical care for infants, children and adolescents. The hospital's mission is to provide state-of-the-art treatment for children in a compassionate atmosphere, as well as to improve the understanding and treatment of pediatric diseases. For more information, visit www.uclahealth.org/mattel.