EFFECT OF BETHANECHOL OR ERYTHROMYCIN ON GASTRIC-EMPTYING IN HOUSES

Objective-To investigate the prokinetic effect of bethanechol and eryt hromycin in the upper gastrointestinal tract of healthy horses by meas uring the gastric emptying (GE) rate of a radioactive meal. Animals-4 healthy adult horses. Procedure-After food was withheld for 12 hours, horses were given 370 MBq of Tc-99m-labeled sulfur colloid incorporate d into egg albumen and 37 MBq of (111)ln-labeled diethyltriaminepentaa cetic acid in 120 mi of water via nasogastric intubation. Intravenousl y administered treatments were 0.9% NaCl solution, erythromycin (0.1 o r 1.0 mg/kg of body weight), or bethanechol (0.25 mg/kg). All drugs we re given in 10 mi of 0.9% NaCl solution. Dual-phase scintigraphic imag es were obtained by use of a gamma camera. The best-fit function was d etermined for each study, and the resultant curves were then analyzed by use of least squares nonlinear regression. Two variables, time to 5 0% emptying of the stomach (T-50) and slope of the emptying curve, wer e derived from the calculated power exponential equation. Conclusions- Treatment had a significant (P < 0.05) overall effect on T-50 of solid -phase GE. The T-50 of bethanechol (30.09 +/- 10.01 minutes), erythrom ycin at 0.1 mg/kg (59.08 +/- 10.01 minutes), and erythromycin at 1 mg/ kg (60.50 +/- 10.01 minutes) were significantly shorter than T-50 afte r saline administration (89.97 +/- 10.01 minutes). There was a trend ( P = 0.09) for the slope of solid-phase GE of bethanechol and erythromy cin (0.1 mg/kg; P = 0.37) to be steeper than that of saline solution. For liquid-phase GE, the T-50 and the slope of bethanechol differed si gnificantly (P less than or equal to 0.05) from those for saline solut ion. Clinical Relevance-Bethanechol and erythromycin significantly inc reased solid-phase GE in healthy horses and may have value for use as prokinetic agents in certain gastrointestinal tract diseases.