Comparison of carprofen and butorphanol as post-surgical analgesics in cats

Post‐operative pain management by a single subcutaneous (SC) injection of carprofen has been found to be effective in cats and dogs. This clinical study compared the analgesic properties of injectable carprofen and butorphanol in 71 healthy cats (0.5–5 years, mean weight 3.24 ± 0.61 kg) undergoing ovariohysterectomy. Cats were randomly assigned to three groups: Group C received carprofen 4 mg kg^?1 SC at intubation and sterile saline 0.08 mL kg^?1 SC at extubation; Group B received sterile saline 0.08 mL kg^?1 SC at intubation and butorphanol 0.4 mg kg^?1 SC at extubation; Group S received sterile saline 0.08 mL kg^?1 SC at intubation and extubation. All cats were pre‐medicated with atropine (0.04 mg kg^?1 SC), acepromazine (0.02 mg kg^?1 SC), ketamine (5 mg kg^?1 SC), and induced IV with ketamine (5 mg kg^?1) and diazepam (0.25 mg kg^?1). Serum biochemistry values were taken at 24 and 48 hours post‐surgically and compared to a pre‐surgical baseline. Behavioral data were collected by a blinded investigator prior to surgery (baseline) and 1, 2, 3, 4, 8, 12, 16, 20, and 24 hours post‐surgery; the data were compiled into composite pain scores on a scale from 0 to 21 and complemented by visual analogue scores (VAS). Scoring was based on changes in behavior, posture, vocalization, and response to interactive stimulation. Cats with pain scores >12 were considered to be moderately painful, received meperidine (4 mg kg^?1 IM), and were excluded from further statistical analyses. Sixty of 71 cats completed the study. Anesthetic time was 88.5 ± 21.8 minutes (mean ± SD). Meperidine was given to one cat in C, three in B, and five in S. There were no significant differences in biochemistry values. There were no significant differences in pain scores between C and B at any time period; B and C pain scores were significantly lower than S at 1, 2, 12, 16, and 20 hours post‐operatively, and C lower than S at 3 and 8 hours post‐surgery. Pain scores decreased over the 24‐hour study in all groups; the greatest decrease in each group was between 4 and 8 hours post‐operatively. In this study, carprofen provided post‐surgical analgesia comparable to butorphanol.     

A comparison of four methods of analgesia in cats following ovariohysterectomy

OBJECTIVE: To evaluate the effectiveness of preoperative administration of oral carprofen, subcutaneous ketoprofen, and local nerve block with bupivacaine in preventing postoperative pain-associated behavior in cats after ovariohysterectomy. ANIMALS: Fifty-two female intact cats. Materials and methods Cats received butorphanol (0.44 mg kg(-1) IM), carprofen (2.2 mg kg(-1) PO), ketoprofen (2.2 mg kg(-1) SQ), or bupivacaine infiltration block (1.1 mg kg(-1) SQ) before surgery. Cortisol and drug concentrations and visual analog scale (VAS) and interactive visual analog scale (IVAS) pain-associated behavior scores were measured 2 hours before and 0, 1, 2, 4, 8, 12, and 24 hours after ovariohysterectomy. RESULTS: Cats receiving butorphanol had significantly increased IVAS scores 2 hours after surgery compared with baseline measurements. Cats receiving carprofen, ketoprofen, and bupivacaine had significant increases from baseline in VAS and IVAS scores 1 and 2 hours after surgery. VAS and IVAS scores for cats receiving bupivacaine were significantly greater 1 and 2 hours after surgery than for cats that received butorphanol. Cats receiving carprofen had significant increases in cortisol 1 hour after surgery and significant decreases 24 hours after surgery compared with baseline measurements. CONCLUSIONS AND CLINICAL RELEVANCE: Preoperative carprofen and ketoprofen have effects on pain-associated behavior similar to butorphanol in cats undergoing ovariohysterectomy. Cats receiving bupivacaine blocks may require additional analgesics immediately after surgery.     

A comparison between pre-operative carprofen and a long-acting sufentanil formulation for analgesia after ovariohysterectomy in dogs

OBJECTIVE: To assess the analgesic efficacy and adverse effects of a novel, long-acting sufentanil preparation in dogs undergoing ovariohysterectomy (OHE). STUDY DESIGN: Blinded, positively controlled, randomized field trial with four parallel treatment groups. ANIMALS: Eighty client owned dogs undergoing elective OHE randomly allocated into four treatment groups (each n = 20). MATERIALS AND METHODS: Three groups received intramuscular (IM) sufentanil (at 10, 15 and 25 microg kg(-1), respectively) and the control group received subcutaneous (SC) carprofen 4 mg kg(-1) SC plus acepromazine 0.05 mg kg(-1) IM as pre-anaesthetic medication. OHE was performed under thiopental/halothane anaesthesia. Visual Analogue Scale (VAS) scores for pain and sedation were awarded and mechanical nociceptive thresholds were measured at the wound and hock before surgery and up to 24 hours after tracheal extubation. Serum cortisol was measured before surgery, during surgery and up to 24 hours after tracheal extubation. Animals with inadequate post-operative analgesia were given rescue medication. RESULTS: In the carprofen group, VAS pain scores were significantly higher, wound tenderness was greater and requirement for rescue analgesia was more than in the sufentanil-treated groups. Sufentanil produced dose dependent analgesia and sedation. All treatment groups showed similar patterns of change for cortisol concentrations. Use of the sufentanil preparation was associated with a relatively high incidence of adverse events. CONCLUSIONS: The long-acting preparation of sufentanil provided excellent post-operative analgesia that was significantly better than that provided by carprofen. However, use of this formulation, in the anaesthetic technique used in the study, resulted in a relatively high incidence of adverse effects. CLINICAL RELEVANCE: Full mu (MOP) opioid agonists provide significantly better post-operative analgesia than nonsteroidal anti-inflammatory drugs after moderately painful surgery. However, the widely recognized adverse effects of opioids may preclude the use of these agents.     

Evaluation of intraperitoneal and incisional lidocaine or bupivacaine for analgesia following ovariohysterectomy in the dog

Objective To determine if intraperitoneal (IP) and incisional (SC) lidocaine or bupivacaine provide analgesia following ovariohysterectomy (OHE). Study Design Prospective, randomized, controlled, blinded clinical trial. Animals Thirty dogs presenting to the Veterinary Teaching Hospital for elective OHE. Methods Dogs were pre‐medicated with acepromazine and butorphanol, induced with thiopental and maintained with isoflurane. They were randomly assigned to three groups: 10 received 8.8 mg kg^?1 2% lidocaine with epinephrine IP (LID); 10 received 4.4 mg kg^?1 0.75% bupivacaine IP (BUP); and 10 received 0.9% saline IP (SAL) upon completion of OHE. All IP doses were standardized to 0.88 mL kg^?1 with saline. An additional 2 mL of undiluted solution was placed SC prior to incisional closure. Dogs were scored at 0.5, 1, 2, 3, 6, 8 and 18 hours post‐extubation by one observer. Dogs were evaluated using a visual analogue scale (VAS) for pain and sedation, and a composite pain scale (CPS) that included physiologic and behavioral variables. Dogs were treated with 0.22 mg kg^?1 butorphanol + acepromazine if their VAS (pain) score was >50. Parametric variables were analyzed using Student's t‐test or repeated measures anova as appropriate. Non‐parametric variables were analyzed by χ²‐test. Results There were no significant differences in age, weight, incision length, surgery time, anesthesia time, or total thiopental dose among groups. Peak post‐surgical pain scores for all groups occurred at 0.5 hours and returned to baseline by 18 hours. Dogs in the BUP group had significantly lower VAS‐pain scores overall than dogs in the SAL group. Seven out of 10 dogs in the SAL group, 4/10 in the LID group and 2/10 in the BUP group were treated with supplemental acepromazine and butorphanol. No differences between groups were detected with the CPS. No adverse side‐effects were observed. Conclusions and clinical relevance Our findings support the use of IP and SC bupivacaine for post‐operative analgesia following OHE in the dog.     

Comparison of oral and subcutaneous administration of buprenorphine and meloxicam for preemptive analgesia in cats undergoing ovariohysterectomy

OBJECTIVE: To compare the effectiveness of preoperative PO and SC administration of buprenorphine and meloxicam for prevention of postoperative pain-associated behaviors in cats undergoing ovariohysterectomy. DESIGN: Randomized controlled study. ANIMALS: 51 female cats (4 to 60 months old; weight range, 1.41 to 4.73 kg [3.1 to 10.4 lb]). PROCEDURE: Cats received 1 of 5 treatments at the time of anesthetic induction: buprenorphine PO (0.01 mg/kg [0.0045 mg/lb]; n = 10), buprenorphine SC (0.01 mg/kg; 10), meloxicam SC (0.3 mg/kg 10.14 mg/lb]; 10), meloxicam PO (0.3 mg/kg; 10), or 0.3 mL of sterile saline (0.9% NaCI) solution SC (control group; 11). Sedation scores and visual analog scale and interactive visual analog scale (IVAS) pain-associated behavior scores were assigned to each cat 2 hours before and at intervals until 20 hours after surgery. RESULTS: Cats receiving meloxicam PO or SC had significantly lower IVAS scores (2.91 and 2.02, respectively), compared with IVAS scores for cats receiving buprenorphine PO (755). Pain-associated behavior scores for cats administered buprenorphine or meloxicam PO or SC preoperatively did not differ significantly from control group scores. Rescue analgesia was not required by any of the cats receiving meloxicam, whereas 3 of 10 cats receiving buprenorphine PO, 2 of 10 cats receiving buprenorphine SC, and 1 of 11 cats receiving the control treatment required rescue analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of pain-associated behavior scores, cats receiving meloxicam PO or SC before ovariohysterectomy appeared to have less pain after surgery than those receiving buprenorphine PO preoperatively.     

Analgesic efficacy of preoperative administration of meloxicam or butorphanol in onychectomized cats

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 705 kg (2.4 to 15.5 lb). PROCEDURE: Cats received meloxicam (0.3 mg/kg [0.14 mg/lb], s.c.) or butorphanol (0.4 mg/kg [0.18 mg/lb], s.c.) 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, i.v. or s.c.) or administration of acepromazine (0.025 to 0.05 mg/kg [0.011 to 0.023 mg/lb], i.v.) 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.     

Comparison of carprofen and pethidine as postoperative analgesics in the cat

The postoperative analgesia and sedation in cats given carprofen (4·0 mg/kg bodyweight by subcutaneous injection preoperatively) was compared to that in cats given pethidine (3·3 mg/kg bodyweight by intramuscular injection postoperatively) in a controlled, randomised, blinded, multicentre clinical trial. Further dosing with the particular analgesic was allowed if a cat was exhibiting unacceptable pain. In total, 57 carprofen cases and 59 pethidine cases were evaluated. Significantly fewer cats in the carprofen group required additional doses of analgesic, and mean pain scores were significantly lower from four hours after ovariohysterectomy, and at 18 to 24 hours after castration, compared to the pethidine group. In conclusion, carprofen provided as good a level of postoperative analgesia as pethidine, but of a longer duration (at least 24 hours) and was well tolerated. It thus provides an option for 'pre-emptive analgesia' in cats about to undergo surgery.     

Comparison of transdermal administration of fentanyl versus intramuscular administration of butorphanol for analgesia after onychectomy in cats

OBJECTIVE: To compare postoperative discomfort assessed by subjective pain score and plasma cortisol concentrations in cats undergoing onychectomy that received analgesia by use of transdermal fentanyl (TDF) patches or an i.m. injection of butorphanol. DESIGN: Randomized prospective clinical trial. ANIMALS: 22 client-owned cats weighing 2.2 to 5 kg (4.84 to 11 lb) undergoing onychectomy. PROCEDURE: Researchers were blinded to which cats received a TDF patch (25 microg/h) 18 to 24 hours prior to surgery or an i.m. injection of butorphanol (0.2 mg/kg (0.09 mg/lb]) at the time of sedation, immediately following extubation, and at 4-hour intervals thereafter for 12 hours. Clinical variables, plasma cortisol concentration, and pain scores were evaluated and recorded 24 hours prior to surgery, at extubation, and 2, 4, 8, 12, 24, 36, and 48 hours after surgery. RESULTS: The TDF group had a lower pain score than the butorphanol group only at 8 hours after surgery. Both groups had significantly lower mean plasma cortisol concentrations 0, 24, 36, and 48 hours after surgery, compared with mean plasma cortisol concentrations prior to surgery. No significant differences in appetite or response to handling the feet were observed between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Our data did not reveal a difference in pain relief between administration of TDF and butorphanol. Plasma cortisol concentrations were not different between groups. Fentanyl appeared to provide equivalent analgesia to butorphanol in cats undergoing onychectomy. The primary advantage of using a TDF patch is that repeated injections are not required.     

Comparison between analgesic effects of buprenorphine, carprofen, and buprenorphine with carprofen for canine ovariohysterectomy

OBJECTIVE: To compare the analgesic effects of buprenorphine, carprofen, and their combination in dogs undergoing ovariohysterectomy. STUDY DESIGN: Prospective, randomized blinded clinical study. ANIMALS: 60 dogs. METHODS: Treatments were buprenorphine 0.02 mg kg(-1), intramuscularly (IM) (group B); carprofen 4 mg kg(-1), subcutaneously (SC) (group C); or a combination of both (group CB). Anesthesia was induced with propofol and maintained with isoflurane. A Dynamic Interactive Visual Analog Scale (DIVAS, 0-100 mm) and the Glasgow Composite Pain Scale (GCMPS, 0-24) were used to evaluate comfort and sedation at baseline, 2, 4, 6, and 24 hours after extubation. Rescue analgesia was provided with buprenorphine (0.02 mg kg(-1)). Wound swelling measurements (WM) and a visual inflammation score (VIS) of the incision were made after surgery and 2, 4, 6, and 24 hours later. p < 0.05 was considered significant. RESULTS: Group C required more propofol (5.0 +/- 1.4 mg kg(-1)) compared with B (3.3 +/- 1.1 mg kg(-1)) and CB (3.2 +/- 0.7 mg kg(-1)); respectively, p = 0.0002 and 0.0001. Rescue analgesia was required in nine dogs. B had a higher GCMPS and DIVAS III score at 6 hours (2.6 +/- 2.5) and (23 +/- 22.5 mm) compared with C (1.0 +/- 1.3, 6 +/- 7.3 mm) and CB (1.5 +/- 1.4, 8 +/- 10.7 mm); respectively, p = 0.02 and 0.006. Group C had a lower sedation score at 2 hours (43 +/- 23.6 mm) compared with B (68 +/- 32.1 mm) and BC (69 +/- 22.1 mm); respectively, p = 0.03 and 0.004. Group B had a higher WM score at 2 hours (3 +/- 0.8 mm) compared with C (2 +/- 0.6 mm) p = 0.01 and at 6 hours (3 +/- 1 mm) compared with C (2 +/- 0.8 mm) and CB (2 +/- 0.8 mm); respectively, p = 0.01 and 0.008. VIS was not different between groups. CONCLUSION AND CLINICAL RELEVANCE: All treatments provided satisfactory analgesia for the first 6 hours and at 24 hours. C and CB pain score and WS were superior to B at 6 hours. No superior analgesic effect was noted when the drugs were combined.     

Alfaxalone or ketamine‐medetomidine in cats undergoing ovariohysterectomy: a comparison of intra‐operative parameters and post‐operative pain

ObjectiveTo compare post-operative pain in cats after alfaxalone or ketamine- medetomidine anaesthesia for ovariohysterectomy (OHE) and physiologic parameters during and after surgery.Study designProspective ‘blinded’ randomized clinical study.AnimalsTwenty-one healthy cats.MethodsCats were assigned randomly into two groups: Group A, anaesthesia was induced and maintained with alfaxalone [5 mg kg^?1 intravenously (IV) followed by boli (2 mg kg^?1 IV); Group MK, induction with ketamine (5 mg kg^?1 IV) after medetomidine (30 μg kg^?1 intramuscularly (IM)], and maintenance with ketamine (2 mg kg^?1 IV). Meloxicam (0.2 mg kg^?1 IV) was administered after surgery. Basic physiological data were collected. At time T = -2, 0, 0.5, 1, 2, 4, 6, 8, 12, 16, 20, and 24 hours post-operatively pain was assessed by three methods, a composite pain scale (CPS; 0–24 points), a visual analogue scale (VAS 0–100 mm), and a mechanical wound threshold (MWT) device. Butorphanol (0.2 mg kg^?1 IM) was administered if CPS was scored =13. Data were analyzed using a general linear model, Kruskal–Wallis analyses, Bonferroni-Dunn test, unpaired t-test and Fisher's exact test as relevant. Significance was set at p < 0.05.ResultsVASs were significantly higher at 0.5, 1, 2, 4, and 20 hours in group A; MWT values were significantly higher at 8 and 12 hours in group MK. Post-operative MWT decreased significantly compared to baseline in both groups. There was no difference in CPS at any time point. Five cats required rescue analgesia (four in A; one in MK).Conclusion and clinical relevanceAnaesthesia with ketamine-medetomidine was found to provide better post-surgical analgesia than alfaxalone in cats undergoing OHE; however, primary hyperalgesia developed in both groups. Alfaxalone is suitable for induction and maintenance of anaesthesia in cats undergoing OHE, but administration of additional sedative and analgesic drugs is highly recommended.     

Carprofen as an analgesic for postoperative pain in cats: Dose titration and assessment of efficacy in comparison to pethidine hydrochloride

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 extuba-tion 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.     

Evaluation of transdermal fentanyl patches for analgesia in cats undergoing onychectomy

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 > or = 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 micrograms/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 after surgery. 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. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of a TFP (25 micrograms/h) for postoperative analgesia in cats undergoing onychectomy with or without surgical sterilization is safe and effective.     

Comparison between meloxicam and carprofen for postoperative analgesia after feline ovariohysterectomy

Eighty female cats presented for ovariohysterectomy were randomly allocated to one of two treatment groups in this assessor-blinded trial. After pre-anaesthetic assessment, the cats were premedicated with acepromazine (0.1 mg/kg). Anaesthesia was induced with thiopentone and maintained with halothane in oxygen. Forty cats received carprofen (4 mg/kg subcutaneously) and 40 received meloxicam (0.3 mg/kg subcutaneously) after anaesthetic induction. Following routine flank ovariohysterectomy the cats were assessed using visual analogue scale scores for pain and sedation over a 20-hour study period. Blood samples were taken before sedation and at 20 hours for serum biochemistry (urea, creatinine, alanine aminotransferase and aspartate aminotransferase). There were no significant differences between the groups for pain and sedation scores. Serum biochemistry values were similar between the groups, with some differences within groups between the pre-sedation and 20-hour values. One cat in the carprofen group and two cats in the meloxicam group required rescue analgesia with intramuscular morphine (0.2 mg/kg).     

A comparison of the analgesic effects of butorphanol with those of meloxicam after elective ovariohysterectomy in dogs

This study was designed to compare the analgesic effects of butorphanol with those of meloxicam following ovariohysterectomy. Fifteen dogs were premedicated with 0.05 mg/kg body weight (BW) of acepromazine by intramuscular (IM) injection, plus 0.2 mg/kg BW of meloxicam by subcutaneous (SC) injection. Fifteen dogs were premedicated with 0.05 mg/kg BW of Acepromazine, IM, plus 0.2 mg/kg BW of butorphanol, IM. Anesthesia was induced with thiopental, and dogs were maintained on halothane. All pain measurements were performed by 1 experienced individual, blinded to treatment. Pain scores and visual analogue scales (VAS) were performed at 2, 3, 4, 6, 8, 12, and 24 hours postpremedication. An analgesiometer was used to determine the pressure required to produce an active avoidance response to pressure applied at the incision line. Pain scores, VAS, and analgesiometer scores were analyzed by using a generalized estimating equations method. A significance level of P < 0.05 was considered significant. Animals that received meloxicam demonstrated significantly lower pain scores and VAS than did animals that received butorphanol in the first 12 hours after surgery. Results of this study suggest that meloxicam will produce better postoperative analgesia than will butorphanol. Mucosal bleeding times were performed on cooperative animals in the study group (11 butorphanol, 13 meloxicam). Bleeding times were performed prior to premedication, 6 hours following premedication, and 24 hours after premedication. The 6- and 24-hour readings were compared with baseline bleeding times by using a paired t-test with a Bonferroni correction (a significance level of P < 0.025). Bleeding times did not change significantly over time.     

Antinociceptive effects of hydromorphone, butorphanol, or the combination in cats

The goal of this study was to assess the antinociceptive activity of a single dose of hydromorphone or butorphanol and to examine the effect of their coadministration on thermal thresholds in cats. Thermal thresholds were measured after IM administration of hydromorphone (0.1 mg/kg), butorphanol (0.4 mg/kg), a combination of butorphanol and hydromorphone (0.4 and 0.1 mg/kg), or saline to each of 6 cats in a randomized, blinded, crossover study design. There were at least 12 days between treatments. Thermal thresholds were measured by a thorax-mounted thermal threshold-testing device specifically developed for cats. Thermal thresholds were measured before treatment, at varying intervals to 12 hours, and at 24 hours after treatments. Data were analyzed by an analysis of variance with a repeat factor of time. Dysphoria was associated with butorphanol administration but not with hydromorphone or hydromorphone-butorphanol combined administration. Vomiting was seen with hydromorphone but not with butorphanol or hydromorphone-butorphanol combined. The control treatment group was stable over time (P = .22; mean threshold, 40.1 degrees C). Thresholds were significantly (P < .05) higher than the control treatment between 15 and 165 minutes for butorphanol, between 15 and 345 minutes for hydromorphone, and between 15 and 540 minutes for hydromorphone-butorphanol combined. The addition of butorphanol to hydromorphone decreased the intensity of antinociception during the 1st 2 hours but extended the duration of observable antinociception from 5.75 to 9 hours. The present study suggests that the combination of butorphanol and a pure OP3 (mu) receptor agonist clinically does not produce increased analgesia and indeed may result in decreased analgesia.     

Effects of butorphanol and carprofen on the minimal alveolar concentration of isoflurane in dogs

OBJECTIVE: To evaluate the effects of butorphanol and carprofen, alone and in combination, on the minimal alveolar concentration (MAC) of isoflurane in dogs. DESIGN: Randomized complete-block crossover study. ANIMALS: 6 healthy adult dogs. PROCEDURE: Minimal alveolar concentration of isoflurane was determined following administration of carprofen alone, butorphanol alone, carprofen and butorphanol, and neither drug (control). Anesthesia was induced with isoflurane in oxygen, and MAC was determined by use of a tail clamp method. Three hours prior to induction of anesthesia, dogs were fed a small amount of canned food without any drugs (control) or with carprofen (2.2 mg/kg of body weight [1 mg/lb]). Following initial determination of MAC, butorphanol (0.4 mg/kg [0.18 mg/lb], i.v.) was administered, and MAC was determined again. Heart rate, respiratory rate, indirect arterial blood pressure, endtidal partial pressure of CO2, and saturation of hemoglobin with oxygen were recorded at the time MAC was determined. RESULTS: Mean +/- SD MAC of isoflurane following administration of butorphanol alone (1.03 +/- 0.22%) or carprofen and butorphanol (0.90 +/- 0.21%) were significantly less than the control MAC (1.28 +/- 0.14%), but MAC after administration of carprofen alone (1.20 +/- 0.13%) was not significantly different from the control value. The effects of carprofen and butorphanol on the MAC of isoflurane were additive. There were not any significant differences among treatments in regard to cardiorespiratory data. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that administration of butorphanol alone or in combination with carprofen significantly reduces the MAC of isoflurane in dogs; however, the effects of butorphanol and carprofen are additive, not synergistic.     

Comparison of carprofen and meloxicam for 72 hours following ovariohysterectomy in dogs

OBJECTIVE: To compare the peri- and post-operative (72 hours) analgesic effects of injectable and orally administered carprofen and meloxicam for ovariohysterectomy in dogs. STUDY DESIGN: Prospective, randomized clinical study. ANIMALS: Forty-three dogs undergoing elective ovariohysterectomy. MATERIALS AND METHODS: Dogs were randomly assigned to receive pre-operative carprofen, meloxicam or sterile saline by subcutaneous injection. Pre-anaesthetic medication was intramuscular acepromazine (0.02 mg kg(-1)) and methadone (0.2 mg kg(-1)). Anaesthesia was induced with either thiopentone or propofol injected to effect, and maintained with isoflurane in oxygen. Visual analogue scores (VAS) for pain and sedation were recorded at 1, 2, 3, 4 and 6 hours following tracheal extubation. Oral medication with the same treatment was continued post-operatively for 3 days, with VAS scores for pain being recorded before, and 2 hours after treatment on each day. Differences between group age, body mass, duration of general anaesthesia, time from treatment injection to tracheal extubation and time from treatment injection to first oral treatment were analysed using one-way analysis of variance and Kruskal-Wallis test. Visual analogue scores for pain and sedation were analysed using a re-randomization method. The significance level was set at p < 0.05. RESULTS: Meloxicam-treated subjects had lower mean VAS than the control group at 2 and 6 hours following tracheal extubation. Control group VAS were more varied than meloxicam scores (at 6 hours) and carprofen scores (at 3 and 6 hours). On the first post-operative day, pre- to post-treatment VAS scores decreased significantly after meloxicam. On day 3, scores in the meloxicam-treated group were significantly lower than control values after treatment. Changes in pre- to post-treatment VAS were greater in animals receiving either meloxicam or carprofen compared with those given saline. CONCLUSIONS AND CLINICAL RELEVANCE: Both carprofen and meloxicam provided satisfactory analgesia for 72 hours following ovariohysterectomy in dogs.     

Evaluation of intravenous administration of meloxicam for perioperative pain management following stifle joint surgery in dogs

OBJECTIVE: To compare preoperative administration of meloxicam and butorphanol to perioperative administration of butorphanol alone for control of postoperative signs of pain in dogs. ANIMALS: 40 client-owned dogs scheduled for surgical repair of a cranial cruciate ligament rupture. PROCEDURE: Group-1 dogs received butorphanol (0.2 mg/kg, IV) and meloxicam (0.2 mg/kg, IV) just prior to surgery. Group-2 dogs received butorphanol just prior to surgery (0.2 mg/kg, IV) and at incision closure (0.1 mg/kg, IV). Pain assessment began 1 to 2 hours before surgery and from extubation until 24 hours after surgery by obtaining the following measurements: the visual analog scale (VAS) score, cumulative pain score (CPS), adjusted cumulative pain score, modified cumulative pain score, and the adjusted modified cumulative pain score (AMCPS). Serum cortisol concentration was measured between 12 to 24 and between 1 to 2 hours prior to surgery, and at 30 minutes, and 1, 2, 4, 8, 18, and 24 hours after extubation. RESULTS: No significant differences between treatment groups were observed in CPS or VAS score. At 8, 9, 10, and 11 hours after extubation, meloxicam-butorphanol-treated dogs had a significantly lower AMCPS, compared with butorphanol-alone-treated dogs. Total serum cortisol concentration (area under the curve) during the measurement period was significantly lower in meloxicam-butorphanol-treated dogs, compared with butorphanol-alone treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Preoperative single dose administration of meloxicam-butorphanol is equivalent to or slightly better than the administration of 2 perioperative doses of butorphanol for the control of postoperative signs of pain in dogs.     

Post-anesthetic hyperthermia in cats

OBJECTIVE: To assess whether administration of hydromorphone and, or ketamine are associated with post-anesthetic hyperthermia in cats undergoing routine surgery. STUDY DESIGN: Prospective clinical study. ANIMALS: Forty healthy, adult cats undergoing ovariohysterectomy (OVH), castration, or declaw surgery. MATERIALS AND METHODS: Each cat was assigned randomly to one of four groups (n = 10). For pre-anesthetic medication, all cats received subcutaneous (SC) glycopyrrolate (0.01 mg kg(-1)) and acepromazine (0.02 mg kg(-1)) and either hydromorphone (0.1 mg kg(-1) SC) or medetomidine (7.5 microg kg(-1) SC). Anesthesia was induced with either diazepam (0.1 mg kg(-1)) and ketamine (5 mg kg(-1)) or propofol (6 mg kg(-1) injected to effect). Group 1 (HDK) received hydromorphone and diazepam-ketamine. Group 2 (HP) received hydromorphone and propofol. Group 3 (MDK) received medetomidine and diazepam-ketamine. Group 4 (MP) received medetomidine and propofol. Rectal temperature was measured before drugs were given, at tracheal extubation and at hourly intervals for 5 hours thereafter. RESULTS: During the 5 hours after anesthesia and surgery, at least one cat in every group had a rectal temperature >39.2 degrees C (102.5 degrees F). The percentage of observations for which a cat's temperature exceeded its pre-anesthetic temperature in groups HDK, HP, MDK, and MP were 86%, 80%, 25%, and 34%, respectively. Maximum temperatures in groups HDK, HP, MDK, and MP were 41.6 degrees C (107.0 degrees F), 40.3 degrees C (104.2 degrees F), 39.2 degrees C (102.6 degrees F), and 40.1 degrees C (104.1 degrees F), respectively. By 5 hours after tracheal extubation there were no differences in temperature between the treatment groups. CONCLUSION: For up to 5 hours following anesthesia and surgery, cats might have body temperatures that exceed their pre-anesthesia body temperatures. The use of hydromorphone is associated with post-anesthetic hyperthermia. However, hyperthermia may occur when other drugs are used. CLINICAL RELEVANCE: Cats given hydromorphone should be closely monitored for hyperthermia following anesthesia and surgery.