More Upsetting News About Irritable Bowel Treatment
Following the expert panel review, the FDA did require that an easy-to-read pamphlet explaining the risk of ischemic colitis, as well as the risk of severe constipation, be distributed to all patients taking the drug. The unprecedented move was ordered in August, when the FDA was aware of about 33 severe cases of both ischemic colitis and severe constipation. The FDA now has received 21 reports of severe constipation.
While it is fair to say the additional reports have prompted the FDA to re-evaluate the drug's benefits and risks, it is still too early to say that Lotronex is responsible for the reported side effects or deaths or that the new reports really reflect any increased risk to patients, an agency spokesperson concedes. Speaking on condition of anonymity, he tells WebMD that the federal agency expected to receive additional reports of ischemic colitis after ordering the consumer pamphlet be distributed because of all the media hype surrounding the issue.
"We are now trying to learn as much as we can about each of these events," he tells WebMD, adding that some of the recent reports refer to events that happened prior to September, when the consumer pamphlet was released.
For its part, Glaxo Wellcome maintains that the risk of ischemic colitis is minimal and probably not associated with Lotronex. When asked whether there is a possible association, Eric Carter, MD, PhD, director of Glaxo Wellcome's U.S. gastrointestinal drug division, says that after extensive animal and human studies of the drug, the researchers there could not find a mechanism to explain the reports of ischemic colitis.
The majority of events have been temporary and reversible, with less than half of the patients requiring hospitalization, Carter notes. This type of ischemic colitis also has been associated with a number of other medications, including oral contraceptives, he notes.
The reports, Carter adds, may simply reflect the true incidence of ischemic colitis in the U.S. Currently, the estimated incidence is about three out of every 10,000 people, but the temporary ischemic colitis reported in association with Lotronex use "probably occurs more frequently [in the general public] than is recognized," he tells WebMD.