The maker of Lotronex, a popular drug for women with irritable bowel syndrome, pulled it off the market Tuesday amid reports of potentially fatal side effects. About 300,000 patients have taken the drug since Glaxo Wellcome began selling it March 15, according to the company. The drug was approved only for women for whom diarrhea is the main symptom of irritable bowel syndrome (IBS), a chronic problem characterized by abdominal pain, diarrhea or constipation. It is the seventh drug in about three years to be taken off the market.
By Nov. 10, the Food and Drug Administration had received reports of at least three deaths that appeared to be linked to the drug, says Victor Raczkowski, deputy director of the FDA drug evaluation office that reviewed Lotronex.
The deaths occurred in women who had developed ischemic colitis - an inflammation of the large bowel from a lack of blood flow -- or severe constipation after taking Lotronex, Raczkowski says. By Nov. 10, he says, the FDA had received reports of 49 cases of ischemic colitis and 21 cases of severe constipation in Lotronex users.
After reviewing the case reports, the FDA advisory committee that had approved Lotronex urged the agency to require a patient-friendly "medication guide" explaining potential risks. In early September, Lotronex became the first drug to carry such a guide. Glaxo Wellcome also revised Lotronex labeling for health professionals to reflect the risks and mailed out letters to alert doctors of the change.
But many of the serious side effects occurred in women who were taking the drug appropriately, Raczkowski says, leading the FDA to continue discussions with the manufacturer about how to manage risks.
The agency suggested restricting Lotronex's use to women with the most severe diarrhea, Raczkowski says. But Richard Kent, chief medical officer at Glaxo Wellcome, says that some of the FDA's proposed restrictions were "non-doable."
That left the company with no choice but to pull Lotronex off the market, Kent says. "We view this as a fairly sad day for women who suffer with IBS," he says. "These women are going to have to go back to old, unproven therapies that hadn't worked in the past."
But consumer advocate Sidney Wolfe, director of Public Citizen's Health Research Group, notes that clinical trials of Lotronex showed it to be barely more effective than a sugar pill.
"The drug doesn't have any unique advantage that really overcomes the deaths and injuries it is causing," says Wolfe, whose group had asked the FDA to ban Lotronex. "This drug should never have been approved."
Wolfe, a longtime critic of the FDA, charges that the agency "bends over backward" to allow drugs to remain on the market.