Llamas (Lama glama) have become increasingly popular as companion animals and livestock in the United States during the last 20 years. Commercially, they are used as breeding animals and their fleece is used for fiber. Common husbandry procedures, such as removal of canine teeth and castration, may necessitate anesthesia, and such procedures are often performed in settings where access to inhalational anesthesia and monitoring equipment is not readily available.
The difficulties encountered with venipuncture in llamas have been reported.1,2 Venipuncture is further complicated by the lack of adequate restraint in many field settings; thus, protocols for anesthesia via IM injection are more appealing. Combinations of xylazine and ketamine are commonly used for induction of anesthesia in llamas, but this mixture is short acting.
Tiletamine, a noncompetitive N-methyl-D-aspartate antagonist,3 and zolazepam, a benzodiazepine, are commercially available as a 1:1 combination.a This drug combination is commonly used as part of the anesthetic management of domestic animals; however, there is limited information on the effect of TZ in New World camelids. When the combination of TZ (4.4 mg/kg, IM) was administered to llamasb and guanacos,4 adverse effects (eg, muscle tremors and rigidity, salivation, chewing, retching, vocalization, and stumbling) were detected during the recovery phase.4
Butorphanol, a synthetic opioid with partial agonist activity at μ-opioid receptors and agonist activity at κ-opioid receptors,5 is commonly used as a premedication prior to anesthesia in many domestic species.6-8 The effects of butorphanol in awake llamas are unpredictable and may result in sedation or excitment.6 Butorphanol resulted in significant antinociception, compared to baseline values, against thermal nociception in awake sheep for 60 minutes after administration9; however, it did not potentiate the anesthetic effects of TZ in goats.10
Acepromazine, a neuroleptic drug belonging to the phenothiazine group,11 is widely used in domestic animals either for sedation or as an anesthetic premedication.7,8,12,13 It has antagonistic properties at dopamine D2 receptors, in addition to actions at catecholamine, 5-hydroxytryptamine 2, and histamine receptors.14 Acepromazine improved the induction of anesthesia with TZ in horses15 and decreased the minimum alveolar concentration of volatile anesthetics in several species, including ruminants.13 To our knowledge, there is no report of the sedative and antinociceptive effects of acepromazine in llamas.
The purpose of the study reported here was to evaluate the sedative, antinociceptive, and physiologic effects of acepromazine and butorphanol during TZ anesthesia in llamas. A question of particular interest was whether butorphanol or acepromazine increased the duration of antinociception in TZ-treated llamas. Thus, the study was designed to test the null hypothesis that acepromazine and butorphanol, alone and in combination, have no effect in increasing the duration of TZinduced antinociception in llamas.
Tiletamine and zolazepam
Pulse-oximeter–estimated hemoglobin saturation
Diastolic arterial blood pressure
Mean arterial blood pressure
Telazol, Fort Dodge Animal Health, Madison, NJ.
Klein L, Tomasic M. Olson K. Evaluation of telazol in llamas (abstr), in Proceedings. Annu Meet Am Coll Vet Anesth 1989;23.
Acepromazine, 10 mg/mL, VEDCO Inc, St Joseph, Mo.
Butorphanol, Fort Dodge Animal Health, Madison, NJ.
Passport-XG, Datascope Corp, Paramus, NJ.
Nellcor N-20V pulse oximeter, Nellcor, Pleasanton, Calif.
Dinamap veterinary blood pressure monitor 8300, Critikon Inc, Tampa, Fla.
i-STAT portable clinical analyzer, Heska Corp, Fort Collins, Colo.
i-STAT-Precision-CG+4-07G02, Abbott Laboratories, Abbott Park, Ill.
Miltex, Lake Success, NY.
Fowler ME. Medicine and surgery of South American camelids. 2nd ed. Ames, Iowa: Iowa State University Press, 1998;69–88, 89–107, 353.
Chapman AG, Meldrum BS. Non-competitive N-methyl-D-aspartate antagonists protect against sound-induced seizures in DBA/2 mice. Eur J Pharmacol 1989;166:201–211.
Sarno RJ, Hunter RL, Franklin WL. Immobilization of guanacos by use of tiletamine/zolazepam. J Am Vet Med Assoc 1996;208:408–409.
Carroll GL, Boothe DM, Hartsfield SM, et al. Pharmacokinetics and pharmacodynamics of butorphanol in llamas after intravenous and intramuscular administration. J Am Vet Med Assoc 2001;219:1263–1267.
Bufalari A, Miller SM, Short CE, et al. The use of propofol for induction of anesthesia in dogs premedicated with acepromazine, butorphanol and acepromazine-butorphanol. N Z Vet J 1997;45:129–134.
Sano T, Nishimura R, Mochizuki M, et al. Effects of midazolambutorphanol, acepromazine-butorphanol and medetomidine on an induction dose of propofol and their compatibility in dogs. J Vet Med Sci 2003;65:1141–1143.
Waterman AE, Livingston A, Amin A. Analgesic activity and respiratory effects of butorphanol in sheep. Res Vet Sci 1991;51:19–23.
Carroll GL, Hartsfield SM, Hambleton R. Anesthetic effects of tiletamine-zolazepam, alone or in combination with butorphanol, in goats. J Am Vet Med Assoc 1997;211:593–597.
Barnhart MD, Hubbell JAE, Muir WW. Evaluation of the analgesic properties of acepromazine maleate, oxymorphone, medetomidine and a combination of acepromazine-oxymorphone. Vet Anaesth Analg 2000;27:89–96.
Doherty TJ, Geiser DR, Rohrbach BW. Effect of acepromazine and butorphanol on halothane minimum alveolar concentration in ponies. Equine Vet J 1997;29:374–376.
Doherty TJ, Rohrbach BW, Geiser DR. Effect of acepromazine and butorphanol on isoflurane minimum alveolar concentration in goats. J Vet Pharmacol Ther 2002;25:65–67.
Marntell S, Nyman G. Effects of additional premedication on romifidine and ketamine anaesthesia in horses. Acta Vet Scand 1996;37:315–325.
Brown SA. Pharmacokinetics: disposition and fate of drugs in the body. In: Adams HR, ed. Veterinary pharmacology and therapeutics. 8th ed. Ames, Iowa: Iowa State University Press, 2001;15–56.
Corletto F, Raisis AA, Brearley JC. Comparison of morphine and butorphanol as pre-anaesthetic agents in combination with romifidine for field castration in ponies. Vet Anaesth Analg 2005;32:16–22.
Gross ME. Tranquilizers, A2-adrenergic agonist, and related agents. In: Adams HR, ed. Veterinary pharmacology and therapeutics. 8th ed. Ames, Iowa: Iowa State University Press, 2001;299–342.
Wilson RP, Zagon IS, Larach DR, et al. Antinociceptive properties of tiletamine-zolazepam improved by addition of xylazine or butorphanol. Pharmacol Biochem Behav 1992;43:1129–1133.
Ghelardini C, Galeotti N, Uslenghi C, et al. Prochlorperazine induces central antinociception mediated by the muscarinic system. Pharmacol Res 2004;50:351–358.
Kyles AE, Waterman AE, Livingston A, et al. Antinociceptive effects of combining low doses of neuroleptic drugs and fentanyl in sheep. Am J Vet Res 1993;54:1483–1488.
Popovic NA, Mullane JF, Yhap EO. Effects of acetylpromazine maleate on certain cardiorespiratory responses in dogs. Am J Vet Res 1972;33:1819–1824.
Howard BW, Lagutchik MS, Januszkiewicz AJ, et al. The cardiovascular response of sheep to tiletamine-zolazepam and butorphanol tartrate anesthesia. Vet Surg 1990;19:461–467.
Lin HC, Baird AN, Pugh DG, et al. Effects of carbon dioxide insufflation combined with changes in body position on blood gas and acid-base status in anesthetized llamas (Llama glama). Vet Surg 1997;26:444–450.
Banchero N, Grover RF. Effect of different levels of simulated altitude on O2 transport in llama and sheep. Am J Physiol 1972;222:1239–1245.
Reynafarje C, Faura J, Villavicencio D, et al. Oxygen transport of hemoglobin in high-altitude animals (Camelidae). J Appl Physiol 1975;38:806–810.
Scoring system used to evaluate sedation in llamas following IM administration of acepromazine, butorphanol, or both drugs in combination or saline (0.9% NaCl) solution.