A randomised double-blind placebo-controlled trial of lidamidine HCL in irritable bowel syndrome.

BACKGROUND

We have previously shown electro-mechanical recto-anal alterations in irritable bowel syndrome patients (Awad R. Neurogastroenterol Motil 1993; 5; 265-271). To assess whether the alpha 2-agonist lidamidine HCL is able to modify these physiological alterations and alleviate clinical symptoms, 50 patients with irritable bowel syndrome were studied in a random, double blind, placebo-controlled trial.

METHODS

Lidamidine HCL (4 mg) or placebo was taken orally t.i.d. with food. Fasting and post-prandial electrical and mechanical activities of rectum and internal anal sphincter were recorded before and at the end of treatment. Recto-anal sensitivity was also tested.

RESULTS

After treatment, post-prandial duration of spontaneous recto-anal inhibitory reflex diminished in the lidamidine group (18.9 +/- 1 vs. 15.1 +/- 1.3 sec; p < 0.05). Amplitude of induced rectoanal inhibitory reflex decreased after lidamidine (24.6 +/- 2.9 vs 17.3 +/- 3 mmHg; p = 0.02). Rectal electrical activity showed no changes during basal and post-prandial periods in any group. Rectal painful sensation decreased after treatment with lidamidine (54.8 +/- 5.4 vs 43.6 +/- 3.5 ml; p < 0.05) as well as with placebo (p < 0.05). Abdominal distension and frequency, severity and duration of pain diminished in both groups (p < 0.05).

CONCLUSION

Lidamidine decreased the augmented mechanical response to food, reduced rectal sensitivity, and relieved symptoms. These facts suggest that in spite of the strong placebo response obtained, lidamidine HCL can become a useful alternative for treatment of patients with irritable bowel syndrome.