LEUVEN, Belgium, Jan. 14 (UPI) -- Researchers in Belgium identified the cause of pain in patients with irritable bowel syndrome and reduced or ended it with a drug used to treat hay fever.

In addition to having extremely sensitive bowels, IBS patients have a significantly increased perception of pain, but the cause wasn't known. Researchers at the University of Leuven identified higher levels of histamine in the gut causing a pain receptor to be hypersensitive, allowing them to test a drug blocking the receptor in IBS patients -- which significantly reduced levels of pain the patients reported.


IBS affects between 25 and 45 million people in the United States, and between 9 and 23 percent of populations globally, according to the International Foundation for Functional Gastrointestinal Disorders.

"Treatment is currently limited to normalising the defecation pattern [of patients]," researchers at the University of Leuven said in a press release. "It cannot reduce or end the abdominal pain experienced by IBS patients. The results of this study may help change that."

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In the first part of the study, published in the journal Gastroenterology, researchers observed that increased levels of histamine in the gut interferes with the histamine 1 receptor on nerves that contain the pain receptor TRPV1 using biopsies from 9 IBS patients and 15 healthy people.

The researchers then recruited 55 IBS patients, randomly giving them ebastine, a drug used in hay fever medication that blocks the histamine 1 receptor, or a placebo for 12 weeks.

In addition to confirming with biopsies from the patients that the drug had reduced histamine in their guts, the researchers found 46 percent of patients taking ebastine had significant relief from pain, compared to 13 percent of patients who received a placebo reporting less pain.

A follow-up study will test the drug's effects in 200 patients with IBS, researchers said.