An evaluation of the use of cisapride in horses with chronic grass sickness (equine dysautonomia)

A clinical trial was carried out to determine the effect of cisapride on rateof passage of digesta and clinical parameters in horses with chronic grass sickness. Sixteen horses were given intramuscular cisapride (0.1 mg kg⁻¹ three times daily) (group I), and 15 received oral cisapride (0.8 mg kg⁻¹ three times daily) (group O). A liquid-phase marker (cobalt-EDTA) and a solid-phase marker (polystyrene pellets) were given by stomach tube at the beginning of each of three consecutive 7 day periods, i.e., before, during and after cisapride therapy. Seven horses in each group completed the rate of passage trial; the remainder provided clinical data only. The rate of passage was found to be significantly faster after cisapride therapy than before. Comparison with data from 20 normal animals showed a trend towards normal rates of passage after therapy. In cases that died during the trial, the caecum and large colon were the main sites of pellet retention. Dry matter intake was significantly higher after therapy than before in group O and dry matter output was higher after treatment than before in both groups. Gut auscultation score increased in both groups in the periods during and after cisapride administration but heart rate was unaffected. Diarrhoea and colic occurred in each group but its occurrence was not associated with cisapride therapy. The results suggest that by increasing gut motility, cisapride is of benefit in the management of selected cases of chronic grass sickness.