Efficacy of massive dose oral gentamicin therapy in nonbloody persistent diarrhea with associated malnutrition

Overgrowth of aerobic and anaerobic bacteria in the upper small intestine is a common finding in persistent diarrhea. We hypothesized that a large dose of broad spectrum, nonabsorbable oral antibiotic would hasten recovery from persistent diarrhea by eradicating aerobic bacterial overgrowth. Sixty-eight patients were randomly assigned to treatment with either oral gentamicin (n = 33) or placebo (n = 35) for a period of 6 days. The two groups were comparable in their clinical features, stool weights, duodenal and fecal microflora, during an initial 24 h observation period before randomization. The proportion of patients recovering within 6 days post-treatment was similar in the antibiotic (45.2%) and placebo (50%) groups. The stool weights in the two groups during 24-72, 72-120, and 120-168 h of the study did not differ significantly. The percent mean weight gain (g) at 168 h post-treatment in the antibiotic (1.0 +/- 5.1) and placebo (1.4 +/- 5.3) groups also did not differ significantly (p = 0.8). A similar proportion of antibiotic- (61.3%) and placebo- (60.7%) treated patients had started to gain weight by the last day of the study. We conclude that oral gentamicin was no more effective than placebo in reducing purge rates, in achieving earlier recovery from diarrhea, and in promoting the earlier onset of weight gain in this study.