Antimicrobial therapy for travelers' diarrhea

Three clinical trials were carried out to examine the efficacy of various antimicrobial agents in the treatment of travelers' diarrhea among students from the United States in Mexico. Thirty-seven subjects received twice daily for five days 160 mg of trimethoprim (TMP) and 800 mg of sulfamethoxazole (SMZ), 38 received 200 mg of TMP, and 35 received a placebo. Another group of students were given 100 mg of furazolidone (47 students) or ampicillin (47 students) four times a day for five days. In the third study, 500 mg of bicozamycin (72 students) or a placebo (68 students) was given four times a day for three days. Most students who received TMP-SMZ (78%), TMP (84%), or bicozamycin (85%) had recovered by 48 hr after initiation of treatment, as compared with 14% and 47% in the corresponding placebo groups and 55% in the furazolidone group. The agents had a positive effect for all etiologic categories, including diarrhea due to enterotoxigenic Escherichia coli and Shigella strains and illness without any established etiologic agents. Treatment failures were unusual with TMP-SMZ, TMP, and bicozamycin therapy (5% vs. 39% for the placebo-treated students). The drugs were well tolerated. The use of TMP-SMZ or TMP alone in the empiric treatment of moderate to severe travelers' diarrhea is advocated.