Antibiotic tackles E. coli; exercise plan may lessen jet lag

Some news on two common ailments, traveler’s diarrhea and jet lag:

A new remedy for traveler’s diarrhea, approved in May by the Food and Drug Administration, is expected on shelves this month.

The antibiotic, brand name Xifaxan (generic rifaximin), is taken orally and stays in the gastrointestinal tract rather than being absorbed in the blood stream. It may have fewer side effects than other antibiotics.

“I think it will become the standard of care,” said Dr. Herbert DuPont, chief of internal medicine and medical director of travel medicine at St. Luke’s Episcopal Hospital in Houston. He conducted clinical trials of the drug but says he has no financial ties to Salix Pharmaceuticals, the manufacturer.

In clinical trials, the new drug was generally well tolerated, but side effects of flatulence, headache and abdominal pain were reported. The FDA approved Xifaxan for treatment of traveler’s diarrhea caused by Escherichia coli in patients 12 and older. The typical dose is three 200-milligram tablets a day, said DuPont, who plans to advise people going to areas where traveler’s diarrhea is common to pack the drug and take it if symptoms strike.

Other doctors say they may not switch to Xifaxan. “The positive thing is, it’s not absorbed [systemically],” said Dr. Brian Terry, a Pasadena physician specializing in travel medicine. The downside, he said, is that the drug is approved only for traveler’s diarrhea caused by E. coli, and travelers usually have no idea which pathogen is to blame for their ailment.

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A body-clock workout

Working out once you reach your destination may help reduce jet lag, according to a study published in June in the American Journal of Physiology -- Regulatory Integrative and Comparative Physiology.

“We were trying to assess whether physical activity, in this case moderate exercise, would be able to help you shift your internal clock system to deal with the effects of jet lag,” said Kenneth P. Wright Jr., assistant professor in the department of integrative physiology at the University of Colorado, Boulder, and a coauthor with Harvard Medical School researchers.

Wright and his team evaluated 18 fit men in the lab, simulating jet lag similar to what would be experienced after traveling to a destination with a time difference of about nine hours.

Half of the men did three 45-minute rounds on a stationary bicycle; the other half didn’t exercise.

The researchers collected blood samples to analyze levels of the hormone melatonin, which vary by time of day and can affect sleep cycles.

The body clocks of men who exercised moved 3 1/2 hours closer to the new time zone, while the body clocks of their non-exercising counterparts moved only 1 1/2 hours closer to the new time zone, Wright says.

“Exercise can help reset the clock by providing an ‘arousing signal,’ ” Wright said, adding that the study doesn’t suggest exercise will replace a long-standing recommendation: Once at your destination, expose yourself to natural light to help reset your internal clock.

For westbound travel, he suggests exercising at your destination about two hours after you would normally have gone to bed at home.

If you usually go to bed at midnight in Los Angeles and are traveling to Honolulu, exercise at 2 a.m. L.A. time, which is 11 p.m. in Honolulu.

The study didn’t examine the effects of eastbound travel.

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Healthy Traveler appears every other week. Kathleen Doheny can be reached at kathleendoheny@earthlink.net.