The mechanisms responsible for the efficacy of cisapride in gastroesophageal reflux disease remain unclear. The current study was designed to test the hypothesis that cisapride decreases esophageal acid exposure by augmenting esophageal motility and improving acid clearance.
Eighteen patients with reflux esophagitis underwent combined 24-h ambulatory esophageal manometry/pH-metry at baseline and then again after 2 wk of cisapride therapy (10 mg q.i.d.).
Esophageal acid exposure was significantly decreased during cisapride therapy (total percentage of time pH was < 4: 8.3 +/- 2.0% at baseline vs 3.8 +/- 0.6% on cisapride). This was not associated with significant changes in contraction amplitude or duration, peristaltic velocity, or the proportion of peristaltic contractions. The number of reflux episodes per hour was unchanged by cisapride therapy; however, cisapride significantly decreased the number of prolonged duration reflux episodes as well as the duration of the longest reflux episode. Although the relative proportion of peristaltic versus nonperistaltic contractions occurring during reflux episodes was unchanged by cisapride therapy, there was a significant increase in the mean number of contractions per minute (both peristaltic and nonperistaltic combined) occurring during reflux episodes.
These data suggest that cisapride decreases esophageal acid exposure by improving esophageal clearance and that this occurs because of an increase in the number of esophageal contractions rather than by augmenting contraction amplitude or duration or the proportion of peristaltic sequences.