Evaluation of oral cisapride and metoclopramide in diabetic autonomic neuropathy: an eight-week double-blind crossover study.

Nineteen diabetic patients with autonomic neuropathy were enrolled in a double-blind crossover study of cisapride, metoclopramide and placebo. Symptoms were evaluated from diary cards and from assessments undertaken at the end of each eight week treatment period. Measurements of oesophageal transit, gastric emptying and whole gut transit were made before treatment began and at the end of each treatment period. Three patients dropped out early in the study, and the results from 16 patients were analysed. The severity of autonomic neuropathy, judged from cardiovascular reflex tests, correlated with delayed oesophageal transit and prolonged gastric emptying, but abnormal oesophageal transit and gastric emptying were often unrelated to the presence of upper gastrointestinal symptoms. Neither cisapride nor metoclopramide had a statistically significant effect on oesophageal transit, gastric emptying or whole-gut transit, nor was any significant effect on symptoms identified, although a trend towards reduced nausea and vomiting with metoclopramide and reduced epigastric fullness and diarrhoea with cisapride was suggested. Upper gastrointestinal symptoms correlate poorly with objective abnormalities of gastrointestinal motor function in diabetes. In consequence, the symptomatic benefit to be expected from correction of these motor abnormalities remains uncertain.