In this study we determined the effects of cisapride on the pyloric muscle in preterm infants. To perform a randomised, double blind, placebo controlled study, two groups each of 16 preterm newborns were given either cisapride (0.2 mg/kg every 8 h) or a placebo for at least 7 days. Infants were studied first on the day when treatment with cisapride or placebo was to be initiated (time 0), and then after 3 (time 1) and 7 days (time 2). In each group, the following parameters were studied by ultrasonography: cross-sectional diameter of the entire pylorus, muscle thickness, and length of the pyloric canal. Also, the mean daily total gastric aspirate volume was studied for the entire week of the study. At time 0, we observed no significant differences between the two groups with respect to diameter, muscle thickness and length of the pyloric muscle. At time 1 and time 2, both diameter and muscle thickness were significantly greater in the cisapride group than in the placebo group. Furthermore, the length of the pyloric canal was significantly greater in the cisapride group than in placebo group at time 2, though not so at time 1. For the entire week of the study, we found a significantly larger mean daily total gastric aspirate volume in the group of infants treated with cisapride compared to the placebo treated group.
Conclusion: Cisapride significantly affects all of the main measurements of the pyloric muscle and causes a significantly larger amount of daily total gastric aspirate volume. Its use to promote feeding intolerance in preterm newborns cannot be recommended.