Currently there are only two drugs FDA approved for irritable bowel syndrome, designed to improve the mechanics of the intestines, and only for women.

Soon, a third medicine may be approved for this disorder affecting one in five Americans. This drug works a different way, and will be for women and men.

“Everything I ate would upset my stomach,” says Bonnie Yaney of Brookville, Pa. The bloating and discomfort of irritable bowel syndrome, or IBS, and the need to always be by a bathroom made shopping and other ordinary activities impossible for her. “You couldn’t go out to eat because you, there were things there that you couldn’t eat.”

She tried the standard treatments, but some didn’t work, or made things worse. “I was nauseated, I was lightheaded,” she describes.

Because the first-line treatments weren’t successful, she was offered a drug FDA approved for traveler’s diarrhea — an antibiotic, rifaximin, brand name Xifaxan.

“When you have this, you are willing to try anything!” she says.

The drug is thought to restore a healthy balance of microbes in the digestive tract.

“We have about 8 billion bacteria that live in our intestine,” says Dr. Paul Lebovitz, a gastroenterologist at Allegheny General Hospital. “That bacteria probably has some role in that interaction with the nervous system of the intestine.”

“It very much helped the mobility, the bloating, and stuff like that,” says Bonnie.

This is what’s called an “off-label” use. It’s in the final phases of research as a treatment for IBS.

“The problem now is because it doesn’t have the indication for irritable bowel syndrome, many of the payors, the insurers, don’t pay for it. So patients have to pay out of pocket for it, or we have support samples,” says Dr. Lebovitz.

With insurance, bonnie pays $75 for a 90-day supply, which she says she extends over six months. “I just have to wait and see how my symptoms are going and then I take it when I need it.” It would otherwise cost $1,800.

Some patients will get it for two weeks, and have really long term response to it, which would be great. But other patients have to stay on it forever, they feel.

Ironically, one of the risks of this antibiotic is an intestinal bacterial infection called C. diff. “It seems to be rare with this antibiotic, but it is an antibiotic and we see that with all antibiotics,” says Dr. Lebovitz.

“I’ll stay on it as long as I can, until it no longer helps me. I’d like to stay on it,” says Bonnie.

Dr. Lebovitz says the drug will go before the FDA soon. Based on studies to date, he expects it will get approved for the treatment of IBS.