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 antibiotic resistance.
"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 approval.
Rifaximin has been used in other countries for the prevention of diarrhea since 1987 and is currently approved for use in 17 countries worldwide.
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 weeks.
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 participants.
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.