title: Comparison of the diuretic effects of medetomidine hydrochloride and xylazine hydrochloride in healthy cats.
abstract: OBJECTIVE
  To investigate dose-related diuretic effects of medetomidine hydrochloride and xylazine hydrochloride in healthy cats.
  
  
  METHODS
  5 sexually intact cats (4 males and 1 female).
  
  
  METHODS
  The 5 cats received each of 11 treatments. Cats were treated by IM administration of saline (0.9% NaCl) solution (control treatment), medetomidine hydrochloride (20, 40, 80, 160, and 320 μg/kg), and xylazine hydrochloride (0.5, 1, 2, 4, and 8 mg/kg). Urine and blood samples were collected 9 times during a 24-hour period. Variables measured were urine volume, pH, and specific gravity; plasma arginine vasopressin (AVP) concentration; and creatinine and electrolyte concentrations as well as osmolality in both urine and plasma.
  
  
  RESULTS
  Both medetomidine and xylazine increased urine production for up to 5 hours after injection. Xylazine had a dose-dependent diuretic effect, but medetomidine did not. Urine specific gravity and osmolality decreased in a dose-dependent manner for both drugs. Free-water clearance increased for up to 5 hours after injection, whereas glomerular filtration rate, osmolar clearance, plasma osmolality, and electrolyte concentrations did not change significantly. Area under the curve for AVP concentrations decreased in a dose-dependent manner for medetomidine but not for xylazine; however, this was not related to diuresis.
  
  
  CONCLUSIONS
  Both medetomidine and xylazine induced profound diuresis in cats by decreasing reabsorption of water in the kidneys. The diuretic effect of medetomidine, including the change in AVP concentration, differed from that of xylazine. Care must be used when administering these drugs to cats with urinary tract obstruction, hypovolemia, or dehydration.
authors.affiliation: Department of Veterinary Medicine, Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori 680-8553, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Murahata
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hikasa
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage*; D000818:Animals; D019540:Area Under Curve; D001127:Arginine Vasopressin / Q000097:blood*; D001774:Blood Chemical Analysis / Q000662:veterinary; D002415:Cats / Q000378:metabolism*; D004231:Diuresis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage*; D016482:Urinalysis / Q000662:veterinary; D014991:Xylazine / Q000008:administration & dosage*
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D001127:Arginine Vasopressin; D014991:Xylazine; D020926:Medetomidine