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New hope for those with irritable bowel syndrome

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By Rhonda Rowland
CNN Medical Unit

ATLANTA, Georgia (CNN) -- The first effective medication for women with a type of irritable bowel syndrome (IBS) could be on the market soon. The drug, called Zelnorm, improves a number of symptoms and is safe according to researchers attending the Digestive Disease Week conference in Atlanta.

"When taken twice a day we saw relief of abdominal pain and discomfort, bloating and constipation," said Dr. Martin Lefkowitz with Novartis Pharma, the drug's maker.

Zelnorm is a new type of medication that activates or stimulates the serotonin 4 receptor.


"The drug increases movement, so it helps those with irritable bowel syndrome characterized by constipation," said Dr. Christine Frissora, who reviewed the safety and efficacy data on Zelnorm at the Weill Medical College of Cornell University. "If you don't give the drug to the right patient, it could make their condition worse."

It's estimated that 15 million Americans suffer from IBS. In some cases the symptoms are so debilitating that patients are unable to work, socialize and in some cases are afraid or embarrassed to leave their homes. One-third of the cases are characterized by constipation, another third by diarrhea and the other third suffer from both. Zelnorm is designed to help those with IBS characterized by constipation.

"Physicians need to be careful in how they use the drug and avoid giving it to inappropriate patients," said Lefkowitz. "We did safety studies in the other group of patients and they haven't run into trouble. But we don't recommend the drug in this group."

Dr. Christine Frissora participated in a study of Zelnorm at the Weill Medical College of Cornell University  

The study followed 1,500 women for 3 months. The most common side effect of the drug is diarrhea, which caused some women to discontinue using it. Other side effects include headache, nausea and abdominal pain.

"I will be using this drug in women aged 20 to 65 who have IBS with abdominal pain, bloating and constipation," said Frissora, "because this is the age group and gender in which Zelnorm has been proven to be safe and effective in thousands of patients."

Another IBS drug, called Lotronex, was pulled from the market earlier this year after reports of deaths, hospitalizations and surgeries.

"Lotronex is for a completely different group of patients," said Frissora, "those with IBS characterized by diarrhea."

Lotronex blocks the serotonin 3 receptor so it's mechanism of action is the complete opposite of Zelnorm's.

"It's a different mechanism, for a different patient," said Frissora. "If I could get my colleagues to understand this, we would be able to maximize the safety and efficacy of Zelnorm and maximize patients' ability to function."

Some doctors say some of the severe side effects seen with Lotronex may have been caused when it was prescribed inappropriately.

"There's a concept at the FDA, with physicians and drug companies that one dose fits all. It just isn't the case. Lotronex is a prime example," said Dr. Michael Wolfe, who's served on FDA advisory committees and is chief of gastroenterology at Boston University School of Medicine. "This is the new frontier in drug therapy. We're using drugs to treat the enteric nervous system. Therefore, there was always the possibility that we're over- or under- treating. In this case I think we may have been over-treating a lot of people."

Dr. Michael Wolfe, a gastroenterologist who has served on FDA advisory committees, says prescribing Zelnorm appropriately is key to its effectiveness  

It's expected that the U.S. Food and Drug Administration will approve Zelnorm for use in women only.

"There were not enough men in our studies to draw conclusions," said Lefkowitz, "but separate studies are planned. However, we have not seen any safety problems in men."

Zelnorm is known generically as tegaserod and will be marketed as Zelmac in countries other than the United States. An advisory committee to the FDA recommended approval, so formal approval could come within weeks.

"I think it has a place," said Wolfe. "In fact the patients I see with IBS -- people with constipation is what I see much more than diarrhea -- so I think this drug will have a very, very important place. How well it works will ultimately be seen in post marketing surveillance studies. There were no safety issues that I saw with this drug."

"To my knowledge this is the only drug effective in treating bloating," said Frissora "Do you know how many women suffer from this? This is very exciting. These women can now live and eat like normal people."



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