title: Pharmacokinetics of intravenously administered caffeine in healthy alpacas (Lama pacos) and llamas (Lama glama).
abstract: OBJECTIVE
  To determine the pharmacokinetic disposition of IV administered caffeine in healthy Lama spp camelids.
  
  
  METHODS
  4 adult male alpacas and 4 adult female llamas.
  
  
  METHODS
  Caffeine (3 mg/kg) was administered as an IV bolus. Plasma caffeine concentrations were determined by use of high-performance liquid chromatography in 6 animals and by use of liquid chromatography-mass spectrometry in 2 llamas.
  
  
  RESULTS
  Median elimination half-life was 11 hours (range, 9.3 to 29.8 hours) in alpacas and 16 hours (range, 5.4 to 17 hours) in llamas. The volume of distribution at steady state was 0.60 L/kg (range, 0.45 to 0.93 L/kg) in alpacas and 0.75 L/kg (range, 0.68 to 1.15 L/kg) in llamas. Total plasma clearance was 44 mL/h/kg (range, 24 to 56 mL/h/kg) in alpacas and 42 mL/h/kg (range, 30 to 109 mL/h/kg) in llamas.
  
  
  CONCLUSIONS
  High-performance liquid chromatography and liquid chromatography-mass spectrometry were suitable methods for determination of plasma caffeine concentrations in alpacas and llamas. Plasma caffeine concentration-time curves were best described by a 2-compartment model. Elimination half-lives, plasma clearance, volume of distribution at steady state, and mean residence time were not significantly different between alpacas and llamas. Intravenous administration of caffeine at a dose of 3 mg/kg did not induce clinical signs of excitement.
authors.affiliation: Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lakritz
authors.forename: John R
authors.initials: JR
authors.lastname: Middleton
authors.forename: David E
authors.initials: DE
authors.lastname: Anderson
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Linden
authors.forename: Richard A
authors.initials: RA
authors.lastname: Sams
authors.forename: Ronald K
authors.initials: RK
authors.lastname: Tessman
authors.forename: Jeff W
authors.initials: JW
authors.lastname: Tyler
mesh_terms: D000818:Animals; D002110:Caffeine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D002161:Camelids, New World / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000662:veterinary; D005260:Female; D006207:Half-Life; D006262:Health; D007275:Injections, Intravenous; D008297:Male; D013045:Species Specificity
chemical_list: D002110:Caffeine