Objectives: To determine the efficacy of antimicrobial treatment in non-dysenteric persistent diarrhoea in a community setting.
Methods: In this double-blind field trial, 156 children aged 4-36 months with persistent diarrhoea not associated with Giardia lamblia infestation seeking treatment in a community outpatient clinic, were randomized to receive a combination of nalidixic acid and metronidazole, metronidazole alone, or placebo for 7 days.
Results: In comparison with placebo, metronidazole treatment did not result in a significant reduction in the mean post-enrollment diarrhoeal duration and stool frequency, increase in the proportion of patients recovered by days 3, 5 and 7 of treatment, and increase in weight gain at days 7 and 14. Comparing the combination of nalidixic acid and metronidazole with metronidazole alone, 17.5% more children treated with the combination recovered by day 3 of treatment (p = 0.08) and the mean stool frequency ascertained on day 7 for the previous 24 h was 26.8% less in them (p = 0.05). The weight gains at days 7 and 14 were similar in the two groups.
Conclusions: These findings indicate that metronidazole offers no therapeutic benefit in persistent diarrhoea not associated with Giardia lamblia and nalidixic acid has only a modest clinical benefit, which is not substantial enough to warrant its routine use.