Abstract
Objective
To evaluate the effects of medetomidine and its antagonism with atipamezole in goats.
Study design
Prospective randomized crossover study with 1 week between treatments.
Animals
Six healthy 3-year-old neutered goats (three male and three female) weighing 39.1–90.9
kg (60.0 ± 18 kg, mean ± SD).
Methods
Goats were given medetomidine (20 μg kg−1, IV) followed, 25 minutes later, by either atipamezole (100 μg kg−1, IV) or saline. Heart and respiratory rate, rectal temperature, indirect blood pressure,
and mechanical threshold were measured, and sedation and posture were scored and blood
samples obtained to measure epinephrine, norepinephrine, free fatty acids, glucose,
and cortisol concentrations at baseline (immediately before medetomidine), 5 and 25
minutes after medetomidine administration, and at 5, 30, 60, and 120 minutes after
the administration of antagonist or saline. Parametric and nonparametric tests were
used to evaluate data; p < 0.05 was considered significant.
Results
Medetomidine decreased body temperature, heart rate, and respiratory rate and increased
mean arterial blood pressure, cortisol, and glucose. Recumbency occurred 89 ± 50 seconds
after medetomidine administration. All goats were standing 86 ± 24 seconds after atipamezole
administration whereas all goats administered saline were sedate and recumbent at
2 hours. Tolerance to compression of the withers and metacarpus increased with medetomidine.
From 5 to 120 minutes after saline or atipamezole administration, there were differences
in body temperature, glucose, and cortisol but none in heart rate or blood pressure.
Three of the six goats receiving saline developed bloat; five of six urinated. After
atipamezole, four of six goats developed piloerection and all goats were agitated
and vocalized.
Conclusion
At the doses used, atipamezole antagonized the effects of medetomidine on recumbency,
sedation, mechanical threshold, and the increase in glucose. Atipamezole increased
the rate of return of cortisol toward baseline, and prevented further decline in rectal
body temperature.
Clinical relevance
Atipamezole may be used to antagonize some, but not all effects of medetomidine.
Keywords
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References
- Alpha-2 adrenoceptor agonists in human anaesthesiology and intensive care.in: Proceedings of the Seventh World Congress of Veterinary Anaesthesia. Berne, Switzerland2000: 13-16
- Chemical capture of free-ranging cattle: immobilization with xylazine or medetomidine, and reversal with atipamezole.Vet Res Commun. 1993; 17: 469-477
- Perioperative stress response in the dog: effect of pre-emptive administration of medetomidine.Vet Surg. 2000; 29: 85-91
- Cardiopulmonary effects of medetomidine in sheep and ponies.Res Vet Sci. 1996; 60: 267-271
- Characterization of the cardiovascular pharmacology of medetomidine in the horse and sheep.Res Vet Sci. 1998; 65: 149-154
- The effect of detomidine and its antagonism with tolazoline on stress-related hormones, metabolites, physiologic responses, and behavior in awake ponies.Vet Surg. 1997; 26: 69-77
- Stress-related hormonal and metabolic responses to restraint, with and without butorphanol administration, in pre-conditioned goats.Lab Anim Sci. 1998; 48: 387-390
- Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration.J Am Vet Med Assoc. 2001; 219: 1263-1267
- The comparative hypoxaemic effect of four α adrenoceptor agonists (xylazine, romifidne, detomidine and medetomidine) in sheep.J Vet Pharmacol Ther. 1997; 20: 446-471
- Cardiopulmonary effects of the α2-adrenoceptor agonists medetomidine and ST-91 in anesthetized sheep.J Pharmacol Exp Ther. 1999; 289: 712-720
- Alterations in components of the melatonin synthetic pathway by acute insulin stress in the rat and Syrian hamster.Brain Res. 1985; 338: 25-32
- Assessing pain by studying neuroendocrine responses.in: Duncan IJH Maloney V Assessing Pain in Farm Animals. Commission of European Communities, Luxembourg1986: 39-48
- Effects of Rompun on acid-base equilibrium and arterial O2 pressure in cattle.Vet Med Rev. 1971; 2/3: 163-169
- The pharmacokinetics and hemodynamic effects of intravenous and intramuscular dexmedetomidine hydrochloride in adult human volunteers.Anesthesiology. 1993; 78: 813-820
- Intravenous clonidine produces hypoxemia by a peripheral alpha2 adrenergic mechanism.J Pharmacol Exp Ther. 1988; 244: 247-252
- Influence of general anesthesia (thiopental sodium) on progesterone and cortisol levels in pregnant goat serum.Arch Exp Vet Med. 1990; 44: 621-625
- Measurement of total and organ-specific norepinephrine kinetics in humans.Am J Physiol. 1984; 247: E21-E28
- Saunders, Philadelphia, PA1991: 812 Textbook of Medical Physiology. 8th edn.
- Balliere Tindall, London, England1991: 60 Principles of Sedation, Analgesia and Premedication. Veterinary Anaesthesia. 9th edn.
- Neuroendocrine markers of stress.Anesth Prog. 1990; 37: 99-105
- Antagonism of xylazine or medetomidine sedation in goats with yohimbine, tolazoline, atipamezole, and saline.Vet Surg. 1999; 28: 133
- Effects of tolazoline and yohimbine on xylazine-induced central nervous system depression, bradycardia, and tachypnea in sheep.J Am Vet Med Assoc. 1987; 190: 423-426
- Acute effects of medetomidine, a selective α2-adrenoceptor agonist, on anterior pituitary hormone and cortisol secretion in man.Acta Endocrinol. 1988; 119: 11-15
- Effects of dexmedetomidine, a selective α2-adrenoceptor agonist, on hemodynamic control mechanisms.Clin Pharmacol Ther. 1989; 46: 33-46
- Medetomidine premedication in dental surgery – a double-blind cross-over study with a new α2-adrenoceptor agonist.Acta Anaesthesiol Scand. 1990; 34: 171-175
- Quantification of equine hoof lameness using an electronic hoof tester.in: Proceedings of the 6th International Conference of Racing Analysts and Veterinarians. Hong Kong, China1988: 325-329
- Comparison of medetomidine and dexmedetomidine as premedication in isoflurane anaesthesia for orthopaedic surgery in domestic sheep.J Vet Med. 2001; 48: 231-241
- Pharmacokinetics and sedative effects of intramuscular medetomidine in sheep.J Vet Pharmacol Ther. 2003; 26: 271-276
- Stress in sheep resulting from management practices.Proc N Z Soc Anim Prod. 1970; 30: 65-76
- Antagonism of xylazine sedation by 4-aminopyridine and yohimbine in cattle.Am J Vet Res. 1982; 43: 2165-2169
- Effects of atipamezole and yohimbine on medetomidine-induced central nervous system depression and cardiorespiratory changes in lambs.Am J Vet Res. 1995; 56: 629-632
- Effect of chronic growth hormone treatment on responses to epinephrine and thyrotropin–releasing hormone in lactating cows.J Dairy Sci. 1986; 69: 44-51
- Medetomidine sedation in sheep.J Vet Med. 1993; 40: 328-331
- Reversal of medetomidine sedation in sheep by atipamezole and yohimbine.Vet Human Toxicol. 1995; 37: 97-99
- Analgesic, behavioral and cardiopulmonary effects of epidurally injected medetomidine (Domitor®) in goats.J Vet Med A. 2000; 47: 65-72
- Effects of aspirin on xylazine-induced hypoxaemia in sheep.Res Vet Sci. 1990; 48: 388-398
- Effect of free fatty acids on the heart.Nature. 1970; 227: 1055-1056
- Some physiological changes in pregnant sheep and goats before, during and after surgical insertion of uterine catheters.Res Vet Sci. 1975; 19: 102-104
- Detomidine reduces the plasma catecholamine but not cortisol concentrations in horses.J Vet Med Ser A. 1991; 38: 153-156
- Sympatho-adrenal activity and the clinical sedative effect of detomidine in horses.Equine Pharm Suppl. 1992; 11: 66-68
- Influence of medetomidine on acid-base balance and urine excretion in goats.Acta Vet Scand. 1994; 35: 283-288
- A pharmacokinetic study including some relevant clinical effects of medetomidine and atipamezole in lactating dairy cows.J Vet Pharmacol Ther. 1999; 22: 368-373
- Medetomidine and atipamezole in sheep: disposition and clinical effects.J Vet Pharmacol Ther. 2000; 23: 401-404
- The effects of medetomidine and its reversal with atipamezole on plasma glucose, cortisol and noradrenaline in cattle and sheep.J Vet Pharmacol Ther. 2000; 23: 379-387
- Suspected tolazoline toxicosis in a llama.J Am Vet Med Assoc. 2000; 216: 227-229
- Anesthetic agents and ancillary drugs.in: Reibold TW Geiser DR Goble DO Large Animal Anesthesia. 2nd edn. Iowa State University Press, Ames, IA, USA1995: 11-64
- Plasma concentrations of cortisol, testosterone, glucose, and blood gases in male goats during anaesthesia with pentobarbitone sodium.Br Vet J. 1990; 146: 36-42
- Pentobarbitone inhibits the stress response to transport in male goats.Br Vet J. 1991; 147: 42-48
- Effects of xylazine on the stress response to transport in male goats.Br Vet J. 1992; 148: 119-148
- Cardiovascular actions of medetomidine and their reversal by atipamezole.Acta Vet Scand (Suppl). 1989; 85: 39-47
- Pharmacological effects of medetomidine in humans.Acta Vet Scand. 1989; 85: 145-147
- Reversal of the sedative and sympatholytic effects of dexmedetomidine with a specific alpha2-adrenoceptor antagonist atipamezole. A pharmacologic and kinetic study in healthy volunteers.Anesthesiology. 1998; 89: 574-584
- Equine stress response to anaesthesia.Br J Anaesth. 1989; 63: 702-709
- The stress response to anaesthesia in ponies: barbiturate anaesthesia.Equine Vet J. 1990; 22: 307-312
- Anesthetic reversal agents.in: American College of Veterinary Surgeons 1993 Veterinary Symposium. 1993: 419-421 (San Francisco, CA, USA)
- Sedative effects of medetomidine and its reversal by atipamezole in llamas.J Am Vet Med Assoc. 1997; 211: 1562-1565
- Influence if idazoxan on the respiratory blood gas changes induced by alpha2-adrenoceptor agonist drugs in conscious sheep.Vet Rec. 1987; 121: 105-107
- The effect of xylazine on body temperature of cattle.Aust Vet J. 1979; 55: 442-443
Article info
Publication history
Accepted:
October 29,
2003
Received:
April 2,
2003
Identification
Copyright
© 2005 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Inc. All rights reserved.