Complications with the use of carfentanil citrate and xylazine hydrochloride to immobilize domestic horses.
Abstract: Carfentanil citrate, the only opioid approved in the United States for immobilizing large exotic animals, increasingly has been used to chemically restrain exotic horses, such as Prezwalski's horses (Equus przewalskii) and wild horses (E caballus). Because carfentanil's duration of action is long and renarcotization may develop 2 to 24 hours after administration of antagonists, a study was designed to compare the physiologic effects of opioid antagonists, using domestic horses chemically restrained with xylazine hydrochloride and carfentanil. The study was terminated after the initial 3 horses developed severe tachycardia and hypertension, which resulted in the death of 1 horse from pulmonary edema. Although it was possible that the clinical findings in these horses may have resulted from use of an inadequate dosage of carfentanil or xylazine, or both, analysis of the results more likely indicated that domestic and exotic horses may respond differently to carfentanil, and domestic horses may not be a good model for use in studies of carfentanil.
Publication Date: 1995-03-15 PubMed ID: 7759336
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- Comparative Study
- Journal Article
Summary
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The study sought to compare the physiological effects of opioid antagonists on domestic horses sedated with xylazine hydrochloride and carfentanil, an opioid used for immobilizing large exotic animals. However, complications arose – severe tachycardia and hypertension – that resulted in the death of one horse and consequently brought the study to an early close.
Objective of the Study
- The research aimed to examine the effects of opioid antagonists on domestic horses that had been chemically restrained using xylazine hydrochloride and carfentanil citrate.
Use of Carfentanil Citrate
- Carfentanil citrate is currently the single approved opioid for immobilizing large exotic animals, such as wild horses and Prezwalski’s horses, in the United States.
- The application of this drug has been escalating due to its long duration of action and the potential development of renarcotization, which usually occurs 2 to 24 hours after administration of antagonists.
Problems with the Research
- The study had to be halted prematurely when the first three horses used for the experiment developed severe tachycardia (a heart rate that exceeds the normal resting rate) and hypertension (high blood pressure).
- One of these horses died due to pulmonary edema, a condition characterized by excess fluid in the lungs that can lead to respiratory failure.
Potential Causes of the Incident
- Although it was considered a possibility that the severe reactions could have resulted from an insufficient dosage of carfentanil or xylazine, it is more plausible that the results were indicative of varied responses to carfentanil between domestic and exotic horses.
- These results suggested that domestic horses may not be the best candidates for research studies involving carfentanil.
Cite This Article
APA
Shaw ML, Carpenter JW, Leith DE.
(1995).
Complications with the use of carfentanil citrate and xylazine hydrochloride to immobilize domestic horses.
J Am Vet Med Assoc, 206(6), 833-836.
Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA.
MeSH Terms
- Analgesics, Opioid / adverse effects
- Analgesics, Opioid / antagonists & inhibitors
- Animals
- Animals, Domestic
- Fentanyl / adverse effects
- Fentanyl / analogs & derivatives
- Fentanyl / antagonists & inhibitors
- Horse Diseases / chemically induced
- Horses / physiology
- Hypertension / chemically induced
- Hypertension / veterinary
- Immobilization
- Naloxone / pharmacology
- Naltrexone / pharmacology
- Pulmonary Edema / chemically induced
- Pulmonary Edema / veterinary
- Tachycardia / chemically induced
- Tachycardia / veterinary
- Xylazine / adverse effects
Citations
This article has been cited 3 times.- Leen JLS, Juurlink DN. Carfentanil: a narrative review of its pharmacology and public health concerns. Can J Anaesth 2019 Apr;66(4):414-421.
- Izwan A, Snelling EP, Seymour RS, Meyer LCR, Fuller A, Haw A, Mitchell D, Farrell AP, Costello MA, Maloney SK. Ameliorating the adverse cardiorespiratory effects of chemical immobilization by inducing general anaesthesia in sheep and goats: implications for physiological studies of large wild mammals. J Comp Physiol B 2018 Nov;188(6):991-1003.
- Meyer LC, Hetem RS, Mitchell D, Fuller A. Hypoxia following etorphine administration in goats (Capra hircus) results more from pulmonary hypertension than from hypoventilation. BMC Vet Res 2015 Feb 3;11:18.
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