Effects of xylazine hydrochloride during isoflurane-induced anesthesia in horses

Eugene Steffey, Peter J Pascoe, Michael J. Woliner, Edwin R. Berryman

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


Objective - To quantitate dose- and time-related anesthetic-sparing effects of xylazine hydrochloride (XYL) during isoflurane-induced anesthesia in horses and to characterize selected physiologic responses of anesthetized horses to administration of XYL. Animals - 6 healthy adult horses. Procedure - Horses were anesthetized 2 times to determine the minimum alveolar concentration (MAC) of isoflurane in O2 and to characterize the anesthetic-sparing effect (MAC reduction) after IV administration of XYL (0.5 and 1 mg/kg of body weight, random order). Selected measures of cardiopulmonary function, blood glucose concentrations, and urinary output also were measured during the anesthetic studies. Results - Isoflurane MAC (mean ± SEM) was reduced by 24.8 ± 0.5 and 34.2 ± 1.9% at 42 ± 7 and 67 ± 10 minutes, respectively, after administration of XYL at 0.5 and 1 mg/kg. Amount of MAC reduction by XYL was dose- and time-dependent. Overall, cardiovascular and respiratory values varied little among treatments. Administration of XYL increased blood glucose concentration; the magnitude of change was dose- and time-dependent. Urine volume increased but not significantly. Conclusions and Clinical Relevance - Administration of XYL reduced the anesthetic requirement for isoflurane in horses. The magnitude of the decrease is dose- and time-dependent. Administration of XYL increases blood glucose concentration in anesthetized horses in a dose-related manner.

Original languageEnglish (US)
Pages (from-to)1225-1231
Number of pages7
JournalAmerican Journal of Veterinary Research
Issue number10
StatePublished - Oct 2000

ASJC Scopus subject areas

  • veterinary(all)


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