Antibiotic May Prevent Traveler's Diarrhea
One Pill per Day May Keep Montezuma's Revenge Away
Editor's note: On May 26, 2004, the FDA approved the
antibiotic rifaximin, brand name Xifaxan, for the treatment of traveler's
May 19, 2004 -- A new antibiotic may safely prevent traveler's
diarrhea without promoting antibiotic resistance, according to a new study.
Researchers say that taking an antibiotic to prevent traveler's
diarrhea has been discouraged in the past because it could encourage the
development of bacteria that are resistant to the antibiotic. This is an
emerging problem that is making a growing number of antibiotics ineffective
against common bacterial infections.
But new research suggests an experimental antibiotic called
rifaximin that stays in the gut and is not readily absorbed by the rest of the
body may be effective in preventing traveler's diarrhea without encouraging
"The characteristics of rifaximin -- it is non-systemic
since it stays in the intestine after taking it by mouth and has been shown to
be 'gut-selective' in clinical trials -- make it an ideal drug for prevention
of diarrhea in international travelers," says researcher Herbert L. DuPont,
MD, chief of internal medicine at St. Luke's Episcopal Hospital in Houston, in
a news release. "It's particularly practical in that it was effective in
preventing illness with as little as one dose a day."
Researchers say traveler's diarrhea, also known as Montezuma's
revenge, affects up to 60% of international travelers and is particularly
common among foreign visitors to Mexico, Latin America, Africa, and southern
Asia. The illness often causes short-term diarrhea and stomach pain but can
also lead to long-lasting diarrhea or irritable bowel syndrome.
Stopping Diarrhea Before It Starts
The antibiotic rifaximin is under consideration for approval by
the FDA and is expected to be marketed under the commercial name Xifaxan after
Rifaximin has been used in other countries for the prevention
of diarrhea since 1987 and is currently approved for use in 17 countries
In the study, presented this week at a meeting of digestive
disease experts, researchers compared the effects of preventive treatment with
the drug vs. placebo in a group of about 200 U.S. college students who traveled
to Guadalajara, Mexico.
The participants were randomly selected to receive 200 mg of
rifaximin once a day, twice a day, or three times a day or a placebo for two
The students were evaluated daily for diarrhea for three weeks
and for side effects for five weeks.
The study showed that 82% of the students that took any of the
three dosage levels of the antibiotic remained free of diarrhea compared with
42% of the placebo group. Among those that did not develop diarrhea, rifaximin
also prevented the occurrence of moderate and severe abdominal pain, cramps,
and excessive gas-related symptoms.
The drug was also safe and well tolerated by the
Researchers say the results suggest that rifaximin could become
an important form of diarrhea prevention for international travelers and also
provide protection against food-borne bioterrorism.