RIFAXIMIN - A NONABSORBED ANTIMICROBIAL IN THE THERAPY OF TRAVELERS DIARRHEA

Background/Aims: Bacterial enteropathogens, the major cause of travele rs' diarrhea, are customarily treated with antibacterial drugs. Rifaxi min, a nonabsorbed antimicrobial was examined as treatment for travele rs' diarrhea. Methods: A randomized, prospective, double-blind clinica l trial was carried out in 72 US adults in Mexico. Patients with acute diarrhea received one of three doses of rifaximin (200, 400 and 600 m g t.i.d.) or trimethoprim/sulfamethoxazole (TMP/SMX, 160 mg/800 mg b.i .d.) for 5 days, Results were compared with data from 2 placebo-treate d historical control populations. Results: The shortest duration of tr eated diarrhea was seen in the group receiving 200 mg rifaximin t.i.d (NS). Clinical failure to respond to treatment occurred in 6 of 55 (11 %) rifaximin-treated subjects versus 5 of 17 (29%) of TMP/SMX-treated subjects (NS). Sixteen of twenty (80%) of the enteropathogens isolated from the rifaximin-treated subjects and 7 of 7 (100%) from the TMP/SM X group were eradicated by treatment (NS). Sixteen of twenty-four (67% ) enteropathogens identified were susceptible to TMP and all 24 were i nhibited by less than or equal to 50 mu g/ml of rifaximin. Rifaximin r educed the number of unformed stools passed during the first 24 h of t reatment when compared with 2 control placebo groups (3.3 versus 5.1; p = 0.008 and 0.0001) and led to a reduced duration of post-enrollment diarrhea (mean values of 43.1 versus 68.1 and 81.9 h; p = 0.001), con clusions: Rifaximin shortened the duration of travelers' diarrhea comp ared with TMP/SMX and 2 earlier studied placebo-treated groups. A poor ly absorbed drug if effective in treating bacterial diarrhea has pharm acologic and safety advantages over the existing drugs.