Rifamycin Approved for Travelers' Diarrhea Caused by Noninvasive E coli

The US Food and Drug Administration (FDA) approved the broad spectrum, semi-synthetic, orally administered, minimally absorbed antibiotic rifamycin (Aemcolo, Cosmo Technologies, Ltd) for the treatment of adult patients with travelers’ diarrhea caused by noninvasive strains of Escherichia coli not complicated by fever or blood in the stool.

As the most common travel-related illness, travelers' diarrhea—defined as 3 or more unformed stools in 24 hours—affects about 10% to 40% of individuals who travel each year. Most commonly caused by bacteria found in water, individuals at highest risk are those who travel to most of Asia as well as the Middle East, Africa, Mexico, and Central and South America, according to the FDA.

Rifamycin's effectiveness was shown in a randomized, placebo-controlled clinical trial during which the drug significantly reduced symptoms of travelers’ diarrhea in adults afflicted with the condition in Guatemala and Mexico. The safety of the antibiotic was revealed in 2 controlled clinical trials which evaluated rifamycin in a total of 619 adults with travelers' diarrhea compared with placebo.

Common adverse reactions included headache and constipation.

The antibiotic was not shown to be effective in patients with diarrhea complicated by fever and/or bloody stool or diarrhea due to pathogens other than noninvasive strains of E coli, according to the FDA. Therefore, it is not recommended for use in such patients. Furthermore, patients with a known hypersensitivity to rifamycin, any of the other rifamycin class antimicrobial agents (such as rifaximin), or any of the components in rifamycin should not take the medication.

"Travelers' diarrhea affects millions of people each year and having treatment options for this condition can help reduce symptoms of the condition," Edward Cox, MD, MPH, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research said in a statement.