Two new treatments for irritable bowel syndrome (IBS) have been approved by the US Food and Drug Administration.

Salix' Xifaxan and Actavis' Viberzi were given the green light to treat adults with IBS with diarrhoea (IBS-D).

Julie Beitz, director of the FDA’s Office of Drug Evaluation III, said: “For some people, IBS can be quite disabling, and no one medication works for all patients suffering from this gastrointestinal disorder.

“The approval of two new therapies underscores the FDA’s commitment to providing additional treatment options for IBS patients and their doctors.”

Viberzi, which contains a new active ingredient, is taken orally twice daily with food and works by activating receptors in the nervous system that can lessen bowel contractions.

Its approval came on the back of two double-blind, placebo-controlled clinical trials involving nearly 2,500 patients that found patients receiving Viberzi was more effective in simultaneously reducing abdominal pain and improving stool consistency than placebo over 26 weeks of treatment.

Meanwhile, Xifaxan can be taken orally three times a day for 14 days, for the treatment of abdominal pain and diarrhoea in patients with IBS-D. Patients who experience a recurrence of symptoms can be retreated with a 14-day treatment course, up to two times.

IBS, which affects 10 to 15% of adults in the US, has a number of symptoms, including pain or discomfort in the abdomen and changes in bowel movement patterns. IBS-D is characterised mainly by loose or watery stools at least 25% of the time.