July 24, 2002Despite side effects risk, FDA approves Zelnorm
The Food and Drug Administration has approved a controversial new treatment for irritable bowel syndrome (IBS) despite allegations that it has led to an alarming rate of side effects. The agency’s approval of Zelnorm comes just weeks after it reinstated another IBS drug, Lotronex, which was taken off the market two years ago because of its side effects.IBS is a condition which affects mostly women, causing abdominal pain and either constipation or diarrhea. Lotronex was designed to treat the diarrhea type, while Zelnorm is intended to treat the constipation type.
The FDA chose to approve Zelnorm despite its marginal effectiveness at relieving the symptoms of IBS. Studies of the drug showed that it was only 6% more successful at treating the condition than a sugar pill and only seems to work effectively for the first three months of treatment.
Zelnorm was close to approval in 2002 when concerns arose about a high number of patients who required gall bladder and other abdominal operations after using the drug. Clinical trials indicated that patients who took Zelnorm required surgery to correct abdominal problems five times as often as those who were given a placebo.
The consumer advocacy group Public Citizen says that apart from the increased risk of abdominal problems, the FDA should not have approved Zelnorm because of the number of ovarian cysts observed among patients. Research indicates that women taking Zelnorm had three times as many ovarian cysts as placebo patients.
Dr. Sidney Wolfe, director of Public Citizen, accused the FDA of downplaying the risk of Zelnorm side effects, just as it had downplayed the risk of Lotronex before its withdrawal. “It’s another serious, reckless mistake for the FDA,” says Dr. Wolfe.