More Upsetting News About Irritable Bowel Treatment
"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
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.
Still, Carter cautions physicians and patients to take the time
to determine whether Lotronex truly is the appropriate treatment. Clinical
studies have shown Lotronex greatly benefits women, with about 75% reporting a
significant improvement in their symptoms over 12 months, but the drug is not
indicated for any men or for women whose predominate IBS symptom is
constipation, he tells WebMD.
"It is not the mandate of a pharmaceutical company to tell
a physician how to practice medicine. Quite frankly, no one can do that,"
he says. But while the company is reluctant to question the clinical judgement
of physicians, the recent reports do demonstrate that the drug is being
prescribed inappropriately to some patients, including patients with a history
of severe intestinal disease, he tells WebMD.
To address this particular issue, the company is launching an
advertising campaign aimed at consumers to help them determine whether Lotronex
is appropriate for them. Despite Glaxo's actions, the controversy surrounding
Lotronex is unlikely to die anytime soon.
Because IBS is a difficult condition to diagnose, it is
possible that a number of the patients prescribed Lotronex do not even have the
condition, Public Citizen says. "We don't think it should have been
approved in the first place," Larry Sasich, PharmD, MPH, the group's lead
researcher, noted in a recent interview with WebMD.
About 70-80% of patients prescribed Lotronex potentially are
being exposed to the risk of ischemic colitis without enjoying any medical
benefit, FDA officials also noted previously. This figure comes from clinical
trials, which indicate that about 80% of the people who participated in the
trials either failed to improve or improved due to other reasons, said Florence
Houn, MD, director of the FDA's office responsible for intestinal drugs.