Antinociceptive properties of tiletamine-zolazepam improved by addition of xylazine or butorphanol.
A combination of tiletamine HCl and zolazepam HCl is frequently used as an anesthetic, but little is known about the antinociceptive properties of tiletamine-zolazepam. The antinociceptive properties of tiletamine-zolazepam alone or combined with xylazine or butorphanol were determined in the adult male rate using the tail-flick test. Changes in tail-flick latency were determined at 15, 45, and 75 min after IP drug administration of sterile water, sodium pentobarbital, morphine, tiletamine-zolazepam, xylazine, butorphanol, and tiletamine-zolazepam plus xylazine or butorphanol. Tail-flick latency approximated 100% maximum possible effect (MPE) at 15-75 min postinjection in morphine-treated rats. Tiletamine-zolazepam, xylazine, and butorphanol alone, at any dose utilized, produced less than 50% MPE. However, the combination of tiletamine-zolazepam with butorphanol or xylazine increased tail-flick latency approximately three times greater than tiletamine-zolazepam alone. These results demonstrate that: a) consonant with earlier findings, analgesia and anesthesia are independent states; b) tiletamine-zolazepam is not an effective combination with respect to analgesia; but c) in concert with appropriate drugs, it can exhibit potent antinociceptive properties.
Wilson
R P
RP
Department of Comparative Medicine, College of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
Zagon
I S
IS
Larach
D R
DR
Lang
C M
CM
D000700:Analgesics / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D002077:Butorphanol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D008297:Male; D009619:Nociceptors / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects; D012890:Sleep / Q000187:drug effects; D013992:Tiletamine / Q000494:pharmacology*; D014991:Xylazine / Q000494:pharmacology*; D015041:Zolazepam / Q000494:pharmacology*
D000700:Analgesics; D014991:Xylazine; D013992:Tiletamine; D015041:Zolazepam; D002077:Butorphanol