ERYTHROMYCIN ACCELERATES SOLID EMPTYING AT THE EXPENSE OF GASTRIC SIEVING

Erythromycin accelerates gastric emptying by inducing antral contractions similar to phase III of interdigestive MMC. These powerful contractions are capable of forcing coin-sized indigestibles out of the stomach. In contrast fed motility is associated with submaximal contractions that fragment (trituration) and propel solids while retaining large (>0.5 mm) pieces for further size reduction (gastric sieving). In this study, using dogs with duodenal fistulas, we tested the hypothesis that erythromycin-induced acceleration of gastric emptying resulted in the passage of inadequately triturated (>0.5 min) chunks of solids into the duodenum. We found that gastric emptying was accelerated by erythromycin (vs 0.15 M NaCl control, P < 0.05). However, the percentage of chyme collected in the >0.5-mm fraction was much greater (P < 0.01) in the erythromycin-treated experiments (63 +/- 9%) than the controls (7 +/- 1%). Correspondingly, while a fine gruel was passed during controls, under erythromycin infusion, most of the solids were emptied as large chunks virtually unchanged from the swallowed pieces. We conclude that erythromycin accelerates gastric emptying at the expense of gastric sieving.