The effects of xylazine, detomidine, acepromazine and butorphanol on equine solid phase gastric emptying rate
Article first published online: 5 JAN 2010
2002 EVJ Ltd
Equine Veterinary Journal
Volume 34, Issue 5, pages 486–492, July 2002
How to Cite
SUTTON, D. G. M., PRESTON, T., CHRISTLEY, R. M., COHEN, N. D., LOVE, S. and ROUSSEL, A. J. (2002), The effects of xylazine, detomidine, acepromazine and butorphanol on equine solid phase gastric emptying rate. Equine Veterinary Journal, 34: 486–492. doi: 10.2746/042516402776117818
- Issue published online: 5 JAN 2010
- Article first published online: 5 JAN 2010
- Received for publication: 2.4.02; Accepted: 6.6.02
- gastric emptying;
- 13C-octanoic acid;
- breath test
The aim of this study was to measure the effects of specific commonly used sedative protocols on equine solid phase gastric emptying rate, using the 13C-octanoic acid breath test (13C-OABT). The gastric emptying of a standard 13C-labelled test meal was measured once weekly in 8 mature horses over two 4 week treatment periods. Each horse acted as its own control. In treatment Period 1, saline (2 ml i.v.), xylazine (0.5 mg/kg i.v.), detomidine (0.01 mg/kg i.v.) or detomidine/butorphanol combination (0.01/0.02 mg/kg i.v.) was administered in randomised order after ingestion of the test meal. During treatment Period 2, test meal consumption was followed by saline, xylazine (1.0 mg/kg i.v.), or detomidine (0.03 mg/kg i.v.) administration, or preceded by acepromazine (0.05 mg/kg i.m.) in randomised order. The 13C:12C ratio of sequential expiratory breath samples was determined by isotope ratio mass spectrometry, and used to measure the gastric half-emptying time, t1/2, and duration of the lag phase, tlag, for each of the 64 tests.
In treatment Period 1, detomidine/butorphanol prolonged both t1/2 and tlag with respect to xylazine 0.5 mg/kg and the saline control (P<0.05). In Period 2, detomidine 0.03 mg/kg delayed each parameter with respect to saline, acepromazine and xylazine 1.0 mg/kg (P<0.001). Xylazine 1.0 mg/kg also lengthened tlag relative to the saline control (P = 0.0004), but did not cause a significant change in t1/2. Comparison of treatment periods showed that the inhibitory effect of detomidine on gastric emptying rate was dose related (P<0.05). These findings may have clinical significance for case selection when these agents are used for purposes of sedation and/or analgesia.