Cardiovascular effects of N-butylscopolammonium bromide and xylazine in horses
Article first published online: 25 JUL 2011
© 2011 EVJ Ltd
Equine Veterinary Journal
Special Issue: Equine Colic. Guest Editors: T.S. Mair and C.J. Proudman. Publication of this supplement was supported by The Horse Trust
Volume 43, Issue Supplement s39, pages 117–122, August 2011
How to Cite
MORTON, A. J., VARNEY, C. R., EKIRI, A. B. and GROSCHE, A. (2011), Cardiovascular effects of N-butylscopolammonium bromide and xylazine in horses. Equine Veterinary Journal, 43: 117–122. doi: 10.1111/j.2042-3306.2011.00400.x
- Issue published online: 25 JUL 2011
- Article first published online: 25 JUL 2011
- [Paper received for publication 10.01.11; Accepted 16.03.11]
- N-butylscopolammonium bromide;
- heart rate
Reasons for performing study: N-butylscopolammonium bromide (NBB) and xylazine are commonly used medications for the treatment of spasmodic colic and other forms of abdominal pain in horses. Both NBB and xylazine exert significant effects on the cardiovascular system and other vital systems of horses.
Objective: To evaluate the effects of i.v. administration of NBB, xylazine, and the combination of NBB and xylazine on heart rate, other commonly measured physiological parameters, cardiac rhythm and blood pressure.
Methods: Six mature horses of mixed breed were used. In a random cross-over design, each horse was given 0.3 mg/kg bwt of NBB i.v., 0.25 mg/kg bwt xylazine i.v., and a combination of 0.3 mg/kg bwt NBB and 0.25 mg/kg bwt xylazine. Heart rate, physiological parameters, cardiac rhythm and indirect blood pressure were recorded at timed intervals before and 60 min following administration.
Results: Heart rate and blood pressure were significantly elevated immediately following administration of NBB or NBB with xylazine. Administration of NBB with xylazine resulted in significantly greater initial and peak blood pressure values than with NBB alone. Administration of xylazine resulted in a decrease in heart rate, with an initial increase in blood pressure followed by a decrease in blood pressure. Sinus tachycardia was seen with NBB, and NBB and xylazine administration. First and second degree atrioventricular block was identified with xylazine administration. Ventricular tachycardia was identified in one horse following NBB and xylazine administration.
Conclusions: Results of this study suggest that the effects of administration of NBB alone or in combination with xylazine to horses with colic, especially to those with systemic cardiovascular compromise, should be considered carefully to assess condition and predict prognosis accurately, and to avoid potential adverse effects.