EFFECT OF ERYTHROMYCIN LACTOBIONATE ON MYOELECTRIC ACTIVITY OF ILEUM,CECUM, AND RIGHT VENTRAL COLON, AND CECAL EMPTYING OF RADIOLABELED MARKERS IN CLINICALLY NORMAL PONIES

Objective-To determine the effect of erythromycin lactobionate (ERY) o n ileocecocolic myoelectric activity and passage of radiolabeled marke rs from the cecum. Animals-6 healthy adult ponies. Procedure-After a 1 2-hour nonfeeding period, 370 MBq of technetium 99m-labeled sulfur col loid in egg albumen and 37 MBq of indium 111-labeled diethyitriaminepe ntaacetic acid in 60 mi of water were administered directly into the c ecal apex. The following drug concentrations were tested: ERY, 0.01,0. 10, 1.0, and 10.0 mg/kg of body weight; ERY, 0.10 mg/kg bolus; and sal ine (0.9% NaCl) solution, 10 ml. All treatments with the exception of the 0.10-mg/kg bolus and saline solution, were infusions administered IV during a 60-minute period in a randomized complete block design. Ea ch treatment was administered 2 times/pony. Dual-phase scintigraphic i mages were obtained, and the best-fit function was determined for each study, using data from the right side. Myoelectric data were collecte d before and after each treatment and analyzed for spike burst rate, r elative activity, and burst duration. Results-The time to 50% emptying (t(50)) after ERY administration was dose dependent, and all treatmen ts, with the exception of the 0.01-mg/kg infusion, resulted in a signi ficantly shorter t(50) than that observed after saline administration (230.2 +/- 17.12 minutes). The shortest t(50) was observed after the 1 .0 mg/kg dosage of ERY (76.9 +/- 22.0 minutes). Although not significa ntly different, the t(50) and beta were shorter (108.6 +/- 25.9 minute s) and steeper after a bolus dose of 0.10 mg/kg of ERY than after infu sion at the same dosage (131.1 +/- 18.7 minutes). Conclusions and Clin ical Relevance-ERY may be a useful prokinetic for prevention or treatm ent of cecal motility dysfunction. The ability of ERY to evoke a simil ar response during the early postanesthetic or postoperative period re mains to be determined.