Influence of simethicone and alverine on stress-induced alterations of colonic permeability and sensitivity in rats: beneficial effect of their association.

Objectives: Alverine, an antispasmodic agent for the treatment of irritable bowel syndrome (IBS), may be combined with simethicone, a protective agent of the mucosa. Stress is a major factor triggering abdominal pain in IBS and causing hypersensitivity to colonic distension in animals through an increased colonic permeability. The antinociceptive effects of alverine and simethicone, separately or in association, were evaluated on stress-induced colonic hypersensitivity to distension in rats. The influence of simethicone on altered permeability was also tested.

Methods: Groups of 8-10 female adult Wistar rats (200-250 g) housed individually were used. Gut paracellular permeability was evaluated after 2 h of partial restraint stress using oral gavage with ⁵¹Cr-EDTA and 24 h of urine collection. The number of abdominal cramps during colonic distension was evaluated in animals equipped with electrodes on their abdominal striated muscles.

Key Findings: At 200 mg/kg p.o. twice a day, but not at lower doses, simethicone reduced stress-induced increase of colonic permeability and hypersensitivity to distension. Administered alone at 10 mg/kg p.o., alverine also reduced stress-induced hypersensitivity to distension; lower doses were inactive. However, alverine administered at an inactive dose with simethicone suppressed stress-induced hypersensitivity to distension.

Conclusions: We conclude that both simethicone and alverine have visceral antinociceptive effects by two different mechanisms and that simethicone exerts a potentiating effect on the antinociceptive action of alverine.