Comparative evaluation of the anticholinergic agent glycopyrrolate as a preanesthetic agent
Short, C.E.; Miller, R.L.
Veterinary Medicine-Small Animal Clinician 73(10): 1269-1273
1978
ISSN/ISBN: 0042-4889 PMID: 252327 Document Number: 128581
Seven dogs were premedicated with atropine (44 mu g/kg i/m) or glycopyrrolate (11 mu g/kg i/m) 10 minutes before anaesthesia with thiamylal (22 mg/kg i/v) in a cross-over experiment. Salivation, heart and respiratory rates and blood pressure were monitored. The times taken for the return of reflexes, regaining righting reflexes and the ability to stand were noted. In a second experiment anaesthesia was induced with thiamylal and maintained with halothane and nitrous oxide in groups of 4 dogs. When anaesthetized, the dogs were injected with glycopyrrolate (5.5, 11 or 22 mu g/kg i/v) and observations were made as above. In a clinical trial 35 dogs and 5 cats were premedicated with glycopyrrolate (11 mu g/kg i/m) 10 minutes before anaesthesia. In dogs, anaesthesia was induced with thiamylal and maintained with methoxyflurane or halothane with or without nitrous oxide. Cats were anaesthetized with ketamine alone or with halothane and nitrous oxide. There was little difference between pretreatment with atropine and glycopyrrolate except that heart rate decreased in atropine-treated dogs. Glycopyrrolate in all three dose rates was effective in keeping heart and respiratory rates and blood pressure normal. Salivation and intestinal peristalsis were suppressed by the two higher dose rates but not completely by the 5.5 mu g/kg level. No adverse effects were seen in the clinical trials on 35 dogs and 5 cats. It was concluded that glycopyrrolate is a safe and effective premedication for dogs and cats.