title: Physiologic and antinociceptive effects following intramuscular administration of xylazine hydrochloride in combination with tiletamine-zolazepam in llamas.
abstract: OBJECTIVE
  To evaluate antinociceptive and selected effects associated with IM administration of xylazine hydrochloride in combination with tiletamine-zolazepam in llamas.
  
  
  METHODS
  8 adult male llamas. Procedures-Each llama received tiletamine-zolazepam (2 mg/kg) combined with either xylazine (0.1, 0.2, or 0.4 mg/kg) or saline (0.9% NaCl) solution IM (treatments designated as TZ-Xy0.1, TZ-Xy0.2, TZ-Xy0.4, and TZ-Sal, respectively) at 1-week intervals. Selected cardiorespiratory variables were assessed during lateral recumbency and anesthesia, and recovery characteristics were recorded. Duration of antinociception was evaluated by clamping a claw every 5 minutes.
  
  
  RESULTS
  Interval between treatment administration and lateral recumbency for TZ-Xy0.4 was shorter than that for TZ-Xy0.1 or TZ-Sal. Mean ± SEM duration of antinociception was longer for TZ-Xy0.4 (51.3 ± 7. 0 minutes), compared with findings for TZ-Xy0.2 (31.9 ± 6.0 minutes), TZ-Xy0.1 (8.1 ± 4.0 minutes), and TZ-Sal (0.6 ± 0.6 minutes). Interval between treatment administration and standing was longer for TZ-Xy0.4 (112 ± 9 minutes) than it was for TZ-Xy0.2 (77 ± 9 minutes) or TZ-Sal (68 ± 9 minutes). Mean heart and respiratory rates during the first 30 minutes for TZ-Sal exceeded values for the other treatments. Administration of TZ-Xy0.2 and TZ-Xy0.4 resulted in Pao2 < 60 mm Hg at 5 minutes after llamas attained lateral recumbency, and values differed from TZ-Sal findings at 5, 10, and 15 minutes; Paco2 was greater for TZ-Xy0.2 and TZ-Xy0.4 than for TZ-Sal at 5, 10, 15, and 20 minutes.
  
  
  CONCLUSIONS
  Xylazine (0.2 and 0.4 mg/kg) increased the duration of antinociception in llamas anesthetized with tiletamine-zolazepam.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA. mrsed@utk.edu
authors.forename: Reza
authors.initials: R
authors.lastname: Seddighi
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Elliot
authors.forename: Brian K
authors.initials: BK
authors.lastname: Whitlock
authors.forename: Christine M
authors.initials: CM
authors.lastname: Egger
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Doherty
mesh_terms: D000818:Animals; D002161:Camelids, New World; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D006339:Heart Rate / Q000187:drug effects; D007273:Injections, Intramuscular; D008297:Male; D010146:Pain / Q000517:prevention & control / Q000662:veterinary*; D012119:Respiration / Q000187:drug effects; D013992:Tiletamine / Q000008:administration & dosage / Q000494:pharmacology*; D014991:Xylazine / Q000008:administration & dosage / Q000494:pharmacology*; D015041:Zolazepam / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D004338:Drug Combinations; C006131:tiletamine, zolazepam drug combination; D014991:Xylazine; D013992:Tiletamine; D015041:Zolazepam