The Newest IBS Medicines

By Jane Farrell

Irritable bowel syndrome (IBS) is an often misunderstood and underdiagnosed condition that affects about 15.3 million people in the United States.

No one remedy works for all patients, so there’s a great medical need to develop new therapies for IBS, Andrew Mulberg, M.D., a gastroenterologist with the Food and Drug Administration (FDA), said in one of the agency’s “Consumer Update” articles.

“There’s a lot of new research about the role of carbohydrates, and specifically a nutrient called polyols, in triggering irritable bowel syndrome in some patients,” Mulberg said in the Consumer Update. “In addition, doctors, scientists and researchers are more closely examining the role of diet in IBS causes and treatments.”

IBS affects the large intestine (colon) but doesn’t cause inflammation or permanent damage to the gastrointestinal system. Symptoms include; diarrhea; constipation; abdominal pain, bloating or cramping; gas; and mucus in stool.

According to the FDA, the symptoms can be intermittent, and can change. Sometimes the pain can be severe, and extreme cases of diarrhea can cause dehydration and even an electrolyte imbalance.

IBS is both widespread and elusive: it’s estimated that it affects up to 20 percent of Americans, and there’s no known cause or cure. Many people may not even know they have the disorder.

“There are many conditions that have a female or male predominance, but we don’t understand why women have a higher prevalence of IBS,” said Mulberg, deputy director of FDA’s Division of Gastroenterology and Inborn Errors Products (DGIEP). There’s also a greater risk of developing IBS if there is a family history of the condition.

Additionally, Mulberg said, depression and anxiety may also play a part. “Some people suffer from depression and IBS. The question is what’s primary or secondary – what came first?” he says. “Either way, antidepressants are not a cure for IBS.”

Treatments that may be effective include changes in diet and exercise. (Food triggers include spicy dishes, caffeine, alcohol and milk products.) Other remedies include either drugs for constipation or for diarrhea.

“IBS is not like other chronic conditions, such as hypertension, which is constant. IBS is a variable condition. Even without treatment, the problem might go away in some patients. But the symptoms might return after a few months,” says Ruyi He, M.D., an internist and medical team leader with DGIEP.

Most recently, FDA approved a new remedy, Linzess (linaclotide) to treat some adults who suffer from IBS with constipation. The drug has also been approved for “chronic idiopathic constipation” – persistent constipation that doesn’t respond to standard treatment. In addition, FDA has approved Amitiza (lubiprostone) for IBS with constipation and one drug for IBS with diarrhea, Lotronex (alosetron). But Ruyi He cautions that “drugs are a last option Patients should try diet and lifestyle changes, especially exercise, before resorting to medication.”

For more information, visit www.fda.gov.