Of a group of 210 American students studying in Guadalajara, Mexico, just under 15 percent of students taking Rifaximin suffered from diarrhea, whereas nearly 58 percent of the students using placebos did. Researchers say the illness is unlikely to build up a resistance to this particular antibiotic, and that it was also effective for people genetically predisposed to diarrhea. One doctor, when asked about the medicine, said doctors don't usually like to prescribe antibiotics for preventative purposes. Salix Pharmaceuticals helped fund the study by the University of Texas Health Science Center in Houston.
A drug already used to treat that tourist nightmare --- traveler's diarrhea --- may also prevent it without causing the antibiotic resistance that can eventually make medicines ineffective, new research suggests.
The experiment involved 210 American students studying Spanish in Guadalajara, Mexico, during the summer of 2003.
Just under 15% of the students who took rifaximin for two weeks suffered from diarrhea, while nearly 54% of those who took placebos came down with the illness, which also includes nausea, vomiting and stomach pain.
Antibiotics have been used for years to treat traveler's diarrhea because it is caused by bacteria found in local food and water.
Last year, the Food and Drug Administration approved rifaximin as a treatment for the illness.
"People who get decked all the time (by traveler's diarrhea) tend not to travel," said lead author Herbert DuPont, of the University of Texas Health Science Center in Houston and chief of internal medicine at St. Luke's Episcopal Hospital.
Phyllis Kozarsky, a professor of medicine and infectious diseases at Emory School of Medicine in Atlanta, said doctors generally don't like to prescribe antibiotics as a preventive measure.
A future study will focus on Thailand, where the bacteria that can cause diarrhea is more invasive than that found in Mexico, Herbert said.
"We have every reason to think it'll work in Asia," he said.
While a germ can become resistant to an antibiotic that is overused, the researchers believe rifaximin has properties that make it unlikely to cause resistance.
Salix helped fund UT's study, and Herbert and some of his colleagues on the study have worked as consultants to the drug maker.