THE EFFECTS OF ATROPINE AND GLYCOPYRROLATE ON HEART-RATES IN CONSCIOUS MATURE GOATS

The effects of intravenously administered atropine (0.2 mg/kg) and gly copyrrolate (0.01 mg/kg) on heart rate were studied in 10 conscious ma ture goats. In a drug cross-over fashion, either atropine, glycopyrrol ate, or 0.9% saline solution was administered using the same volume (0 .05 mL/kg). Atropine and glycopyrrolate caused a significant increase in heart rate (P <.05), whereas saline solution (0.09%) did not. The m ean percent changes in heart rate from baseline were similar for atrop ine and glycopyrrolate up to 14 minutes after administration. Thereaft er, glycopyrrolate had a significantly greater mean change in heart ra te than atropine, ie, up to 29 minutes (P <.05). Within the atropine g roup, the mean percentage changes in heart rate became significantly l ower compared with the initial increase (1 minute) starting at II minu tes. For the glycopyrrolate group, the mean percent changes became sig nificantly lower starting at 27 minutes. Glycopyrrolate and atropine h ad a mean percentage change in heart rate of greater than 1.0%, up to 31 and 22 minutes, respectively. At the doses used, glycopyrrolate had longer duration of action than atropine but the magnitude of increase was similar. (C) Copyright 1995 by The American College of Veterinary Surgeons