Comparison of sedative and cardiorespiratory effects of medetomidine and medetomidine-butorphanol combination in dogs.
OBJECTIVE
Sedative, cardiorespiratory, and analgesic effects of intramuscular administration of medetomidine (40 micrograms/kg of body weight)-glycopyrrolate (0.01 mg/kg) and medetomidine (10 micrograms/kg)-butorphanol (0.2 mg/kg)-glycopyrrolate (0.01 mg/kg) combinations were compared. Additional evaluations were done on reversal of medetomidine, using atipamezole (200 micrograms/kg. IV), after 90 minutes of medetomidine-induced sedation.


METHODS
Crossover study, with each dog receiving each drug combination at 1-week intervals.


METHODS
Six 2-year-old English hound-type dogs.


METHODS
Arterial blood pressure, ECG, respiratory rate, tidal volume, minute volume, arterial blood gas tensions, and serum biochemical variables were measured before, during, and after sedation. Analgesia was evaluated by needle prick on the skin and tail clamp.


RESULTS
Heart rate decreased significantly from 100 beats/min to < 40 beats/min within 3 minutes of injection of medetomidine and medetomidine and butorphanol (MB). Mean arterial blood pressure in both groups were maintained above 100 mm of Hg throughout the recording period. There was no significant difference between medetomidine and MB in respiratory rate, tidal volume, and minute ventilation. Hypoxemia (PaO2 < 60 mm of Hg) was observed at 10 and 20 minutes in 2 dogs given MB. Atipamezole administration in the dogs given medetomidine significantly increased PaO2, and returned the values to baseline. Needle prick analgesia duration was longer in the medetomidine (80 +/- 7.7 minutes) than MB (56.0 +/- 19.2 minutes) group. Tail pinch analgesia was variable in both groups. Duration of lateral recumbency was longer after medetomidine (90 +/- 0 minutes) than MB (73.5 +/- 19.0 minutes).


CONCLUSIONS
Medetomidine and MB were effective combination for mildly invasive procedures.


CONCLUSIONS
MB induced a shorter period of analgesia and recumbency than did medetomidine.
Ko
J C
JC
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0136, USA.
Bailey
J E
JE
Pablo
L S
LS
Heaton-Jones
T G
TG
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001639:Bicarbonates / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002077:Butorphanol / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000097:blood; D018592:Cross-Over Studies; D004285:Dogs; D004347:Drug Interactions; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006454:Hemoglobins / Q000378:metabolism; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D020926:Medetomidine; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism; D010313:Partial Pressure; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors
D000701:Analgesics, Opioid; D001639:Bicarbonates; D006454:Hemoglobins; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D010108:Oxyhemoglobins; D002245:Carbon Dioxide; D020926:Medetomidine; D002077:Butorphanol; D010100:Oxygen