Dose-related thermal antinociceptive effects of intravenous hydromorphone in cats.
OBJECTIVE
To describe the dose-related thermal antinociceptive effects of intravenous (i.v.) hydromorphone in cats.


METHODS
Randomized, blinded, crossover design.


METHODS
Seven adult cats (3.5-7.4 kg), two spayed females, and five neutered males.


METHODS
Hydromorphone (0.025, 0.05, or 0.1 mg kg(-1)) was administered i.v.. Skin temperature and thermal threshold were measured before and at selected time points to 720 minutes post-administration. Statistical analysis of mean thermal threshold and skin temperatures over time for each dose and between doses was by way of a split-plot model and post hoc Bonferroni t-tests. p < 0.05 was considered significant.


RESULTS
A significant difference from baseline for mean thermal threshold was identified for the 0.05 mg kg(-1) dose (5-80 minutes, peak thermal threshold 46.9 +/- 6.2 degrees C) and 0.1 mg kg(-1) dose (5-200 minutes, peak thermal threshold 54.9 +/-0.2 degrees C). The thermal threshold was significantly greater after the 0.1 mg kg(-1) dose from 5 to 200 minutes compared to the 0.025 mg kg(-1) and 0.5 mg kg(-1) doses. The thermal threshold was significantly greater from 35 to 80 minutes for the 0.05 mg kg(-1) dose when compared with the 0.025 mg kg(-1) dose. Skin temperature was significantly increased from 35 to 140 minutes following the 0.1 mg kg(-1) dose.


CONCLUSIONS
A dose-related antinociceptive effect was demonstrated for i.v. hydromorphone in cats.


CONCLUSIONS
Hydromorphone at doses less than 0.1 mg kg(-1) has a modest antinociceptive effect and a short duration of action. At a dose of 0.1 mg kg(-1) i.v., onset of analgesia is rapid with a clinically useful duration of effect, but is associated with a rise in skin temperature.
Wegner
Kirsten
K
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA.
Robertson
Sheilah A
SA
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D004091:Hydromorphone / Q000008:administration & dosage / Q000494:pharmacology*; D007262:Infusions, Intravenous / Q000662:veterinary; D008297:Male; D010146:Pain / Q000517:prevention & control / Q000662:veterinary*; D012684:Sensory Thresholds / Q000187:drug effects*; D012881:Skin Temperature / Q000187:drug effects*
D000701:Analgesics, Opioid; D004091:Hydromorphone