Cardiovascular and haemodynamic effects of intramuscular doses of xylazine in conscious sheep.
OBJECTIVE
To determine if a commonly used analgesic dose of xylazine has detrimental cardiovascular or haemodynamic effects in sheep.


METHODS
A physiological study following intramuscular administration of xylazine.


METHODS
Xylazine (50 micrograms/kg) was injected intramuscularly into six healthy Merino ewes. For 60 min heart rate, mean arterial blood pressure and cardiac output were recorded; arterial blood samples for the measurement of blood gas tensions were also collected.


RESULTS
There were no significant changes in heart rate, mean arterial blood pressure, cardiac output or arterial carbon dioxide tension. A slight degree of arterial hypoxaemia was noted with a 10% reduction in arterial oxygen tension values at 30 min.


CONCLUSIONS
The minimal changes to cardiovascular and respiratory values in this study verify the safety of previously suggested analgesic dosing regimens for sheep. Previously reported hypoxaemic effects in sheep as a result of intravenous xylazine administration appear to be reduced as a result of intramuscular administration.
Grant
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Department of Anaesthesia and Intensive Care, University of Adelaide, Adelaide, South Australia 5005.
Upton
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RN
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D007273:Injections, Intramuscular / Q000662:veterinary; D012119:Respiration / Q000187:drug effects; D012756:Sheep / Q000502:physiology*; D014991:Xylazine / Q000008:administration & dosage / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000700:Analgesics; D014991:Xylazine