The aim of this study was to titrate the optimal dose of
carprofen for single dose usage, for alleviating
postoperative pain, under a double-blind and randomised protocol, using both negative and positive controls. Renal tolerance was assessed by screening plasma
urea and
creatinine. Pre- and postoperative assessment of
pain and sedation was made using a dynamic and interactive visual analogue scoring system in 60 cats undergoing ovariohysterectomy. The cats were randomly assigned to one of six groups: (1)
carprofen at 1.0 mg/kg subcutaneously (sc); (2)
carprofen at 2.0 mg/kg sc; (3)
carprofen at 4.0 mg/kg sc; (4)
pethidine at 5.0 mg/kg intramuscularly (im), (5)
pethidine at 10.0 mg/kg im: and (6) no
analgesics (injection of saline). All
injections were given postoperatively on tracheal extubation and administered in a double-blind manner. Assessments were made up to 20 hours post extubation. Prior to induction and at 20 hours post extubation, blood samples were taken for laboratory analysis of the
urea and
creatinine content to check for any adverse effect on renal function. Cats given
pethidine did not appear more sedated than the groups receiving
carprofen or saline. Cats receiving
carprofen were in less
pain postoperatively overall, with 4.0 mg/kg being the most effective dose rate (significantly better than the other doses of
carprofen at four and eight hours post extubation). The highest dose of
pethidine provided significantly better
analgesia than the highest dose of
carprofen up to two hours post extubation, but from two to 20 hours post extubation
carprofen at 4.0 mg/kg provided significantly better
analgesia than the
pethidine. None of the
analgesic regimens appeared to affect renal function adversely, as measured by
urea and
creatinine levels.