Influence of medetomidine on stress-related neurohormonal and metabolic effects caused by butorphanol, fentanyl, and ketamine administration in dogs.
OBJECTIVE
To examine stress-related neurohormonal and metabolic effects of butorphanol, fentanyl, and ketamine administration alone and in combination with medetomidine in dogs.


METHODS
10 Beagles.


METHODS
5 dogs received either butorphanol (0.1 mg/kg), fentanyl (0.01 mg/kg), or ketamine (10 mg/kg) IM in a crossover design. Another 5 dogs received either medetomidine (0.02 mg/kg) and butorphanol (0.1 mg/kg), medetomidine and fentanyl (0.01 mg/kg), medetomidine and ketamine (10 mg/kg), or medetomidine and saline (0.9% NaCI) solution (0.1 mL/kg) in a similar design. Blood samples were obtained for 6 hours following the treatments. Norepinephrine, epinephrine, cortisol, glucose, insulin, and nonesterified fatty acid concentrations were determined in plasma.


RESULTS
Administration of butorphanol, fentanyl, and ketamine caused neurohormonal and metabolic changes similar to stress, including increased plasma epinephrine, cortisol, and glucose concentrations. The hyperglycemic effect of butorphanol was not significant. Ketamine caused increased norepinephrine concentration. Epinephrine concentration was correlated with glucose concentration in the butorphanol and fentanyl groups but not in the ketamine groups, suggesting an important difference between the mechanisms of the hyperglycemic effects of these drugs. Medetomidine prevented most of these effects except for hyperglycemia. Plasma glucose concentrations were lower in the combined sedation groups than in the medetomidine-saline solution group.


CONCLUSIONS
Opioids or ketamine used alone may cause changes in stress-related biochemical variables in plasma. Medetomidine prevented or blunted these changes. Combined sedation provided better hormonal and metabolic stability than either component alone. We recommend using medetomidine-butorphanol or medetomidine-ketamine combinations for sedation or anesthesia of systemically healthy dogs.
Ambrisko
Tamas D
TD
Department of Veterinary Internal Medicine, Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori 680-8553, Japan.
Hikasa
Yoshiaki
Y
Sato
Kota
K
D000698:Analgesia / Q000379:methods / Q000662:veterinary*; D000704:Analysis of Variance; D000818:Animals; D019540:Area Under Curve; D001786:Blood Glucose; D002077:Butorphanol / Q000009:adverse effects*; D018592:Cross-Over Studies; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D004338:Drug Combinations; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005283:Fentanyl / Q000009:adverse effects*; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007649:Ketamine / Q000009:adverse effects*; D008297:Male; D020926:Medetomidine / Q000627:therapeutic use*; D009638:Norepinephrine / Q000097:blood; D013312:Stress, Physiological / Q000139:chemically induced / Q000188:drug therapy / Q000662:veterinary*
D001786:Blood Glucose; D004338:Drug Combinations; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D007649:Ketamine; D020926:Medetomidine; D002077:Butorphanol; D005283:Fentanyl; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine