Objective—To determine analgesic efficacy and adverse effects of preemptive administration of meloxicam or butorphanol in cats undergoing onychectomy or onychectomy and neutering.
Design—Randomized controlled study.
Animals—64 female and 74 male cats that were 4 to 192 months old and weighed 1.09 to 7.05 kg (2.4 to 15.5 lb).
Procedure—Cats received meloxicam (0.3 mg/kg [0.14 mg/lb], SC) or butorphanol (0.4 mg/kg [0.18 mg/lb], SC) 15 minutes after premedication and prior to anesthesia. A single blinded observer measured physiologic variables, assigned analgesia and lameness
scores, and withdrew blood samples for each cat at baseline and throughout the 24 hours after surgery. Rescue analgesia (butorphanol, 0.4 mg/kg, IV or SC) or administration of acepromazine (0.025 to 0.05 mg/kg [0.011 to 0.023 mg/lb], IV) was allowed.
Results—Meloxicam-treated cats were less lame and had lower pain scores. Cortisol concentration was higher at extubation and lower at 1, 5, and 12 hours in the meloxicam-treated cats. Fewer meloxicam-treated cats required rescue analgesia at 3, 5, 12, and 24 hours after extubation. General impression scores were excellent or good in 75% of meloxicam-treated cats and 44% of
butorphanol-treated cats. There was no treatment effect on buccal bleeding time; PCV and BUN concentration decreased in both groups, and glucose concentration decreased in meloxicam-treated cats.
Conclusions and Clinical Relevance—Preoperative administration of meloxicam improved analgesia for 24 hours without clinically relevant adverse effects in cats that underwent onychectomy or onychectomy and neutering and provided safe, extended analgesia,
compared with butorphanol. (J Am Vet Med Assoc 2005;226:913–919)
Objective—To evaluate disposition of butorphanol
after IV and IM administration, effects on physiologic
variables, and analgesic efficacy after IM administration
Design—Nonrandomized crossover study.
Animals—6 healthy adult male llamas.
Procedure—Butorphanol (0.1 mg/kg [0.045 mg/lb] of
body weight) was administered IM first and IV 1
month later. Blood samples were collected intermittently
for 24 hours after administration. Plasma butorphanol
versus time curves were subjected to pharmacokinetic
analysis. Two months later, butorphanol
(0.1 mg/kg) was administered IM, and physiologic
variables and analgesia were assessed.
Results—Extrapolated peak plasma concentrations
after IV and IM administration were 94.8 ± 53.1 and
34.3 ± 11.6 ng/ml, respectively. Volume of distribution
at steady state after IV administration was 0.822 ±
0.329 L/kg per minute and systemic clearance was
0.050 ± 0.014 L/kg per minute. Slope of the elimination
phase was significantly different, and elimination
half-life was significantly shorter after IV (15.9 ± 9.1
minutes) versus IM (66.8 ± 13.5 minutes) administration.
Bioavailability was 110 ± 49% after IM administration.
Heart rate decreased and rectal temperature
increased. Somatic analgesia was increased for various
periods. Two llamas became transiently sedated,
and 2 became transiently excited after butorphanol
Conclusions and Clinical Relevance—Although IV
administration of butorphanol results in a short halflife
that may limit its analgesic usefulness, the elimination
half-life of butorphanol administered IM is likely
to be clinically useful. The relationship among plasma
butorphanol concentration, time, and analgesia
differed with the somatic analgesia model; clinically
useful analgesia may occur at lower plasma concentrations
than those reported here. (J Am Vet Med
Objective—To evaluate efficacy and safety of using
transdermal fentanyl patches (TFP) for analgesia in
cats undergoing onychectomy.
Design—Randomized controlled clinical trial.
Animals—45 client-owned cats weighing ≥ 2.7 kg
(5.9 lb) undergoing onychectomy, onychectomy and
ovariohysterectomy, or onychectomy and castration.
Procedure—Cats were randomly assigned to be
treated with a TFP (25 µg/h) or butorphanol; TFP were
applied a minimum of 4 hours before surgery (approx
8 hours prior to extubation). Rectal temperature, heart
rate, respiratory rate, force applied by the forelimbs,
and serum fentanyl concentration were measured,
and temperament, recovery, degree of sedation,
severity of pain, severity of lameness, and appetite
were scored before and periodically for up to 40 hours
Results—Cats treated with a TFP had better recovery
scores at 2 of 4 evaluation times, lower sedation
scores at 2 of 8 evaluation times, and lower pain
scores at 6 of 8 evaluation times, compared with cats
treated with butorphanol. Use of a pressure-sensitive
mat to evaluate force applied by the forelimbs did not
reveal any differences between groups but did reveal
a significant difference between preoperative and
postoperative values. Mean ± SD serum fentanyl concentrations
were 1.56 ± 1.08, 4.85 ± 2.38, 4.87 ± 1.56,
and 4.35 ± 2.97 ng/ml approximately 8, 24, 32, and 48
hours, respectively, after TFP placement.
Conclusion and Clinical Relevance—Results suggest
that use of a TFP (25 µg/h) for postoperative analgesia
in cats undergoing onychectomy with or without
surgical sterilization is safe and effective. (J Am
Vet Med Assoc 2000;217:1013–1020)