Prokinetic effects of erythromycin on the ileum, cecum, and pelvic flexureof horses during the postoperative period

Objective-To evaluate the effect of erythromycin on motility of the ileum, cecum, and pelvic flexure of horses during the postoperative and post-recov ery periods. Animals-8 healthy adult horses. Procedure-Horses were anesthetized and bipolar electrodes were implanted in smooth muscle of the ileum, cecum, and pelvic flexure. Approximately 4, 16 , and 24 hours (postoperative recording sessions) and at least 8 days (post -recovery recording session) after surgery, myoelectric activity was record ed before and after administration of erythromycin (0.5 mg/kg). Results-Following erythromycin administration, myoelectric activity was inc reased in the ileum during all postoperative recording sessions but not dur ing the post-recovery recording session. Myoelectric activity was increased in the cecum following erythromycin administration only during the post-re covery recording session. Myoelectric activity was increased in the pelvic flexure following erythromycin administration during all recording sessions . During several recording sessions, there were short periods during which myoelectric activity was significantly decreased following erythromycin adm inistration. Conclusions and Clinical Relevance-Results suggest that erythromycin has an effect on myoelectric activity of the ileum, cecum, and pelvic flexure in horses; however, prokinetic effects of erythromycin administered during the postoperative period were not always the same as effects obtained when the drug was administered after horses had recovered from the effects of surgi cal implantation of recording devices. Therefore, caution must be exercised when extrapolating results of prokinetic studies in healthy animals to ani mals with abnormal gastrointestinal tract motility.