Rifaximin seems to break the vicious cycle of relapse in some patients.
Clostridium difficile–associated diarrhea (CDAD) recurs after initial therapy in up to 50% of patients, and an unlucky few suffer multiple relapses. Treatments including prolonged antibiotic courses, antibiotic combinations, probiotic regimens, and even infusions of "healthy" stool to recolonize the gut have been effective in some patients. Researchers now report promising preliminary data on a simpler alternative.
Eight patients who had experienced four to eight episodes of CDAD within the previous year were treated with a 2-week "chaser" course of the oral nonabsorbable rifampin analog rifaximin, immediately after completing a course of vancomycin for relapsed CDAD. All patients were asymptomatic when beginning rifaximin and remained asymptomatic for a mean of 233 days after treatment (in contrast to a mean of 10 days after treatment for previous episodes). Repeat toxin assays were negative in six patients who were tested after symptoms resolved. One patient had a relapse 10 days after finishing rifaximin and received a second course, with apparent resolution of disease after 9 months. In this patient, a stool culture performed before the first rifaximin course yielded C. difficile sensitive to rifaximin, while after the second course, high-level rifaximin resistance had developed.
Comment: Rifaximin is FDA-approved for the treatment of traveler's diarrhea. It has good in vitro activity against C. difficile and minimal activity against many of the aerobic bacterial components of healthy stool — an excellent combination for treating CDAD. The "chaser" approach used here warrants further study, although the apparent ease of inducing drug resistance — always likely when rifampin is used alone — may turn out to be a substantial problem.
— Abigail Zuger, MD
Published in Journal Watch General Medicine March 1, 2007
Citation(s):
Johnson S et al. Interruption of recurrent Clostridium difficile–associated diarrhea episodes by serial therapy with vancomycin and rifaximin. Clin Infect Dis 2007 Mar 15; 44:846-8.