Role of loperamide and placebo in management of irritable bowel syndrome (IBS)

Abstract
Symptom scores, stool data, and the transit of a standard, solid meal were measured in 28 patients with irritable bowel syndrome (IBS) during baseline conditions and after five weeks of treatment with placebo and loperamide, given as a flexible dosage regime in the form of a double-blind, cross-over trial. All patients had undergone a comprehensive series of diagnostic investigations and had failed to respond to dietary supplementation with coarse wheat bran (10–30 g daily). Loperamide treatment accelerated gastric emptying, compared with placebo (1.2±0.1 vs 1.5±0.1 hr; P<0.001) and delayed both small bowel (6.2±0.3 vs 4.3±0.3 hr P<0.001) and whole gut transit (56±5 vs 42±4 hr; P<0.01). Eighteen patients said they felt better taking loperamide compared with placebo and, at follow up, 15 of these patients remained satisfied with the effects of the drug. Most symptoms improved significantly on placebo compared with the baseline period, but three of these [diarrhea (P<0.01), urgency (P<0.01) and borborygmi (P<0.05)] showed a further significant improvement on loperamide. Improvement in diarrhea was not associated with any change in stool weight but was associated with reductions in stool frequency (P<0.001), passage of unformed stools (P<0.01), and incidence of urgency (P<0.001). Urgency was the only symptom that was significantly more common in the success group, compared with the group who did not feel better on loperamide.