Loperamide oxide in acute diarrhoea: a double-blind, placebo-controlled trial. The Dutch Diarrhoea Trialists Group

Loperamide is an established treatment of acute diarrhoea with only rare adverse reactions. The pro-drug loperamide oxide is converted to loperamide by anaerobic bacteria in the lower alimentary tract. With the use of loperamide oxide, it was expected to obtain similar antidiarrhoeal efficacy as with loperamide, but with a lower dose and a lower plasma concentration. The incidence of adverse reactions might be reduced with the use of loperamide oxide.

Loperamide oxide (0.5 and 1 mg capsules) was compared with placebo in a double-blind treatment of acute diarrhoea of 242 patients. Relief of diarrhoea was significantly more rapid for either dose of loperamide oxide than for placebo. Both the investigators' and the patients' global assessment of the treatment significantly favoured the loperamide oxide 1 mg capsule, but not 0.5 mg, over placebo. Adverse experiences were less frequent in the drug-treated than in the placebo-treated group.

These results suggest that loperamide oxide 1 mg produces effective relief of diarrhoeal symptoms.