Zelnorm Deemed Safe for IBS Constipation
Watchdog Group Still Worried, but GI Docs Happy
WebMD News Archive
"There is nothing in these data to support the idea that
this [ovarian cyst] is a signal that such problems happen with increased
frequency in [people who take] Zelnorm," Tougas tells WebMD.
The data show nothing because the study was poorly designed,
counters pharmacologist Elizabeth Barbehenn, PhD. Barbehenn is a former FDA
scientist who now serves as a research analyst for Public Citizen.
"It's a big joke," Barbehenn tells WebMD. "There
was no control group, so you could say anything you want. Half the people
dropped out before the study ended. And there was no protocol for whether the
drug caused problems. They let the investigators just decide whether they
thought adverse events were related to the drug."
Private practice gastroenterologist and Johns Hopkins clinical
instructor James Novick, MD, headed a major clinical trial of Zelnorm. He says
ovarian cysts simply aren't a real problem for people taking Zelnorm.
"As far as I understand, the ovarian cyst concern holds no
water whatsoever," Novick tells WebMD. "The most common side effect was
headache -- 3% more in [Zelnorm] patients than in placebo patients. Then 5% of
patients get what they consider to be diarrhea, mostly in the first couple of
weeks of treatment. Best of all, there is no interaction with other drugs, not
even SSRI antidepressants. That doesn't seem to happen, which is a real
Novick notes that the only other concern with Zelnorm was that
several patients taking the drug needed gallbladder surgery.
Initially there was a scare the drug might be causing
gallstones symptoms -- that was the data that led the FDA to slow approval, he
says. "That was far more troubling than the ovarian cyst worry. But now it
appears the drug has no effect on the gallbladder. The FDA had a look at the
data before approving the drug, and they were happy enough."
Doctors who treat IBS patients are optimistic but cautious
about using Zelnorm, says gastroenterologist Eri Ehrenpreis, MD, director of
the gastroenterology fellowship training program at the University of
"For the GI doc on the street, the impression has been
positive," Ehrenpreis tells WebMD. "Everybody is a bit gun-shy about
using serotonin-manipulating drugs. Remember, with Lotronex we learned of the
danger only six months after approval. But I think this is a safe drug. If you
look at these studies on IBS patients, these are really very intensively
conducted trials. There are hundreds and hundreds and hundreds of patients who