Effect of meloxicam and butorphanol on minimum alveolar concentration of isoflurane in rabbits.
OBJECTIVE
To determine the effects of meloxicam and butorphanol on minimum alveolar concentration of isoflurane (MAC(ISO)) in rabbits.


METHODS
10 healthy young adult female rabbits.


METHODS
Rabbits were anesthetized with isoflurane on 3 occasions in a blinded, randomized complete block design to determine the MAC(ISO) associated with administration of meloxicam (0, 0.3, or 1.5 mg/kg, PO) and butorphanol (0.4 mg/kg, IV). The MAC(ISO) was determined by use of a paw clamp technique as the end-tidal concentration of isoflurane halfway between the values that allowed or inhibited purposeful movement. Rectal temperature, end-tidal CO2 concentration, heart rate, oxygen saturation, and arterial blood pressure were measured to evaluate cardiopulmonary function.


RESULTS
Mean +/- SE MAC(ISO) in saline (0.9% NaCl) solution-treated rabbits was 2.49 +/- 0.07% and was not significantly different from that associated with administration of meloxicam at 0.3 mg/kg (2.56 +/- 0.07%) or 1.5 mg/kg (2.66 +/- 0.07%). Butorphanol significantly reduced the MAC(ISO) to 2.30 +/- 0.07% when administered with saline solution alone, 2.27 +/- 0.07% when administered with 0.3 mg of meloxicam/kg, and 2.33 +/- 0.07% when administered with 1.5 mg of meloxicam/kg. The percentage reduction in MAC(ISO) was significantly greater for rabbits that received butorphanol and meloxicam at either dose, compared with butorphanol and saline solution.


CONCLUSIONS
Results indicated that meloxicam does not have a direct isoflurane-sparing effect and does not interfere with the anesthetic-sparing effect of butorphanol in rabbits.
Turner
Patricia V
PV
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
Kerr
Carolyn L
CL
Healy
Amanda J
AJ
Taylor
W Michael
WM
D018712:Analgesics, Non-Narcotic / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002077:Butorphanol / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007530:Isoflurane / Q000493:pharmacokinetics*; D000077239:Meloxicam; D011817:Rabbits; D013843:Thiazines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D013843:Thiazines; D013844:Thiazoles; D007530:Isoflurane; D002077:Butorphanol; D000077239:Meloxicam