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.     

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.     

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.     

Effect of postoperative analgesic protocol on limb function following onychectomy in cats

OBJECTIVE: To evaluate the analgesic effects of topical administration of bupivacaine, i.m. administration of butorphanol, and transdermal administration of fentanyl in cats undergoing onychectomy. DESIGN: Prospective study. ANIMALS: 27 healthy adult cats. PROCEDURE: Cats were randomly assigned to 1 of 3 treatment groups, and unilateral (left forefoot) onychectomy was performed. Gait analysis was performed before and 1, 2, 3, and 12 days after surgery. All forces were expressed as a percentage of the cat's body weight. RESULTS: On day 2, peak vertical force (PVF) was significantly decreased in cats treated with bupivacaine, compared with cats treated with butorphanol or fentanyl. The ratio of left forelimb PVF to PVF of the other 3 limbs was significantly lower on day 2 in cats treated with bupivacaine than in cats treated with fentanyl. No significant differences in vertical impulse (VI) were found between groups on any day. Values for PVF, VI, and the PVF ratio increased progressively following surgery. However, for all 3 groups, values were still significantly decreased, compared with baseline values, 12 days after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that limb function following onychectomy is significantly better in cats treated with fentanyl transdermally or butorphanol i.m. than in cats treated with bupivacaine topically. Regardless of the analgesic regimen, limb function was still significantly reduced 12 days after surgery, suggesting that long-term analgesic treatment should be considered for cats undergoing onychectomy. Irrigation of the surgical incisions with bupivacaine prior to wound closure cannot be recommended as the sole method for providing postoperative analgesia in cats undergoing onychectomy.     

Evaluation of signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a four-point regional nerve block

OBJECTIVE: To evaluate signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a 4-point regional nerve block. DESIGN: Prospective, randomized, double-blind clinical trial. ANIMALS: 20 cats. PROCEDURE: All cats received buprenorphine (0.01 mg/kg [0.004 mg/lb], IM) preoperatively. One forelimb of each cat also received bupivacaine (1 mg/kg [0.45 mg/lb] of a 0.75% solution) administered as a 4-point regional nerve block. After onychectomy, discomfort (lameness, foot reaction, and pain) scores were evaluated by 2 experienced observers 2, 4, 6, 8, 24, and 168 hours postoperatively. Complication (hemorrhage, swelling, and infection) scores were evaluated 24 and 168 hours postoperatively. Surgeries were performed by 1 experienced veterinary surgeon. Rescue analgesia was provided if needed. RESULTS: 6 cats required rescue analgesia postoperatively. There was no difference in discomfort or complication scores between control limbs and limbs in which a nerve block was administered. Additionally, there was no difference in discomfort and complication scores between cats that did or did not require rescue analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: Bupivacaine administered as a 4-point regional nerve block in addition to a systemic analgesic did not decrease discomfort or complication scores in cats undergoing forelimb onychectomy.     

Analgesic effect of pre-operative etodolac and butorphanol administration in dogs undergoing ovariohysterectomy

The analgesic, bleeding, and renal effects of dogs pre‐medicated with etodolac with and without butorphanol were evaluated. Twenty‐four 1‐year‐old healthy dogs, weighing 19 ± 3 kg (mean ± SD) were randomly assigned to four treatment groups (n = 6): control (C), etodolac (E), butorphanol (B), and etodolac with butorphanol (EB). Etodolac (12–14 mg kg^?1 PO) was given 1 hour before propofol induction and isoflurane maintenance anesthesia. Butorphanol (0.4 mg kg^?1 IV) was given immediately following endotracheal intubation. Control dogs received only propofol (8 mg kg^?1 to effect) and isoflurane anesthesia. All dogs were mechanically ventilated to maintain Pe ′CO₂ between 35 and 45 mm Hg (4.7–6.0 kPa). Lactated Ringer's solution was given at 10 mL kg^?1 hour^?1 during anesthesia. Plasma cortisol concentrations were assessed 1 day prior to surgery (baseline), immediately prior to anesthesia induction, and every 30 minutes until 5 hours following extubation, and 1 day after surgery. Total duration of anesthesia was 50 minutes and total surgery duration was 30 minutes. Isoflurane concentration area under the curve (AUC) over time during the anesthesia was compared among treatment groups. Buccal mucosal bleeding time (BMBT) was assessed 1 day before E administration and during surgery. Urine GGT to urine creatinine ratio, BUN, and plasma creatinine were taken daily from 1 day before to 3 days after surgery. Behavioral pain scores (numerical rating scale) were assessed by two observers blinded to the treatment during the 5‐hour recovery period at 30 minute intervals until 3 hours, and again at 5 hours after extubation. All data were analyzed using anova . Multiple comparisons were performed if the anova was significant. Alpha value was set at 0.05. Plasma cortisol concentrations significantly increased from time of extubation in all the treatment groups. They did not return to the baseline until 5, 2.5, 1.5, and 1.5 hours after extubation in the C, B, E, and EB groups, respectively. Isoflurane AUC was not significantly different among treatment groups. Dogs treated with EB had significantly less behavioral pain than all other groups throughout the 5‐hour recovery period. No significant difference was found between treatment groups or within treatment groups over time in BMBT, or any renal variables. This study demonstrated that (i) pre‐operative administration of E provides profound analgesia during the post‐operative period without renal or bleeding side‐effects in dogs undergoing OHE; and (ii) a combination of butorphanol–etodolac provides the best analgesic effect during the post‐operative period based on the behavioral pain score.     

Plasma fentanyl concentrations and analgesic effects during full or partial exposure to transdermal fentanyl patches in cats

OBJECTIVE: To compare plasma fentanyl concentrations and analgesic efficacy during full or partial exposure to 25-microg/h transdermal fentanyl patches (TFPs) in cats undergoing ovariohysterectomy. DESIGN: Randomized controlled clinical trial. ANIMALS: 16 client-owned cats. PROCEDURE: Cats were randomly assigned to receive full or partial exposure to a TFP; patches were applied approximately 24 hours prior to ovariohysterectomy. Rectal temperature, heart rate, respiratory rate, blood glucose concentration, and blood pressure were measured and pain severity was assessed periodically for 72 hours after patch application. Venous blood samples were collected for determination of plasma fentanyl concentration 0, 6, 12, 18, 24, 36, 48, 60, and 72 hours after patch application. RESULTS: Mean +/- SD steady state plasma fentanyl concentration in cats in the full TFP exposure group (1.78 +/- 0.92 ng/mL) was significantly greater than concentration in cats in the partial exposure group (1.14 +/- 0.86 ng/mL). Steady state plasma fentanyl concentrations were evident between 18 and 72 hours after patch application. Subjective scores used to evaluate analgesic efficacy were not significantly different between treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that delivery of fentanyl from TFPs can be reduced by decreasing the amount of exposed surface area. In cats weighing < 4 kg (9 lb), exposure to half a 25-microg/h TFP appears to provide adequate analgesia following ovariohysterectomy.     

Cardiorespiratory responses and plasma cortisol concentrations in dogs treated with medetomidine before undergoing ovariohysterectomy

OBJECTIVE: To evaluate effects of medetomidine on anesthetic dose requirements, cardiorespiratory variables, plasma cortisol concentrations, and behavioral pain scores in dogs undergoing ovariohysterectomy. DESIGN: Randomized, prospective study. ANIMALS: 12 healthy Walker-type hound dogs. PROCEDURE: Dogs received medetomidine (40 micrograms/kg [18.2 micrograms/lb] of body weight, i.m.; n = 6) or saline (0.9% NaCl) solution (1 ml, i.m.; 6) prior to anesthesia induction with thiopental; thiopental dose needed for endotracheal intubation was compared between groups. Ovariohysterectomy was performed during halothane anesthesia. Blood samples were obtained at various times before drug administration until 300 minutes after extubation. Various physiologic measurements and end-tidal halothane concentrations were recorded. RESULTS: In medetomidine-treated dogs, heart rate was significantly lower than in controls, and blood pressure did not change significantly from baseline. Plasma cortisol concentrations did not increase significantly until 60 minutes after extubation in medetomidine-treated dogs, whereas values in control dogs were increased from time of surgery until the end of the recording period. Control dogs had higher pain scores than treated dogs from extubation until the end of the recording period. CONCLUSION AND CLINICAL RELEVANCE: Administration of medetomidine reduced dose requirements for thiopental and halothane and provided postoperative analgesia up to 90 minutes after extubation. Dogs undergoing ovariohysterectomy by use of thiopental induction and halothane anesthesia benefit from analgesia induced by medetomidine administered prior to anesthesia induction. Additional analgesia is appropriate 60 minutes after extubation.     

Use of a continuous, local infusion of bupivacaine for postoperative analgesia in dogs undergoing total ear canal ablation

OBJECTIVE: To determine whether addition of a continuous, local infusion of bupivacaine would improve postoperative analgesia in dogs undergoing total ear canal ablation. DESIGN: Randomized controlled trial. ANIMALS: 16 dogs undergoing total ear canal ablation (12 unilaterally and 4 bilaterally with > 1 month between procedures). PROCEDURE: Dogs were randomly allocated to receive morphine (0.25 mg/kg [0.11 mg/lb]) at the end of the procedure (10 procedures) or morphine and a continuous, local infusion of bupivacaine (0.13 to 0.21 mg/kg/h [0.06 to 0.1 mg/lb/h]; 10 procedures). Dogs were observed for 48 hours after surgery. Additional doses of morphine were administered up to every 4 hours in dogs with signs of severe pain. RESULTS: Temperament, sedation, analgesia, and cumulative pain scores were not significantly different between groups any time after surgery. Recovery score was significantly higher for dogs that received bupivacaine than for control dogs 2 hours after extubation but not at any other time. Serum cortisol concentration was not significantly different between groups at any time but, in both groups, was significantly increased at the time of extubation, compared with all other observation times. Total number of additional doses of morphine administered was not significantly different between groups. Bupivacaine was not detected in the plasma of any of the dogs that received the local bupivacaine infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that addition of a continuous, local infusion of bupivacaine did not significantly increase the degree of postoperative analgesia in dogs that underwent total ear canal ablation and were given morphine at the end of surgery.     

Comparison of preoperative carprofen and postoperative butorphanol as postsurgical analgesics in cats undergoing ovariohysterectomy

OBJECTIVE: To compare carprofen to butorphanol, with regard to postsurgical analgesic effects, duration of analgesia, and adverse side effects. STUDY DESIGN: Blinded, randomized clinical study. ANIMALS: Seventy-one cats, 0.5-5 years of age, weighing 3.24 +/- 0.61 kg, undergoing ovariohysterectomy (OHE). METHODS: Cats were premedicated with subcutaneous atropine (0.04 mg kg(-1)), acepromazine (0.02 mg kg(-1)), and ketamine (5 mg kg(-1)). Anesthesia was induced with ketamine (5 mg kg(-1)) and diazepam (0.25 mg kg(-1)) given intravenously, and maintained with isoflurane. There were three treatment groups: group C (4 mg kg(-1) carprofen SC at induction), group B (0.4 mg kg(-1) butorphanol SC at end of surgery), and group S (0.08 mL kg(-1) of sterile saline SC at induction and end of surgery). Behavioral data were collected using a composite pain scale (CPS), prior to surgery (baseline) and 1, 2, 3, 4, 8, 12, 16, 20, and 24 hours post-surgery. Interaction scores were analyzed separately. Cats with CPS scores >12 received rescue analgesia (meperidine, 4 mg kg(-1), intramuscular). RESULTS: Sixty cats completed the study. The CPS scores did not differ significantly between groups C and B at any time period. CPS scores for groups B and C were significantly increased for 12 hours post-surgery, and in group S for 20 hours. Both group C and B CPS scores were significantly lower than group S in this 20-hour postoperative period, except at 4 hours (B and C) and at 3 and 8 hours (B alone). Interaction scores for group C returned to preoperative baseline 4 hours after surgery, while both groups B and S remained increased for at least 24 hours post-surgery. Nine cats required meperidine. CONCLUSION: In this study, carprofen provided better postsurgical analgesia than butorphanol. Clinical relevance Neither drug completely abolished pain, however preoperative carprofen provided better pain control compared with postoperative butorphanol in the 24-hour period following OHE surgery in cats.     

Transdermal fentanyl patches in small animals

Fentanyl citrate is a potent opioid that can be delivered by the transdermal route in cats and dogs. Publications regarding transdermal fentanyl patches were obtained and systematically reviewed. Seven studies in cats and seven studies in dogs met the criteria for inclusion in this review. Dogs achieved effective plasma concentrations approximately 24 hours after patch application. Cats achieved effective plasma concentrations 7 hours after patch application. In dogs, transdermal fentanyl produced analgesia for up to 72 hours, except for the immediate 0- to 6-hour postoperative period. In cats, transdermal fentanyl produced analgesia equivalent to intermittent butorphanol administration for up to 72 hours following patch application.     

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 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.     

Postoperative hypoxemia and hypercarbia in healthy dogs undergoing routine ovariohysterectomy or castration and receiving butorphanol or hydromorphone for analgesia

OBJECTIVE: To determine frequency and severity of postanesthetic hypoxemia and hypercarbia in healthy dogs undergoing elective ovariohysterectomy or castration and given butorphanol or hydromorphone for analgesia. DESIGN: Prospective trial. ANIMALS: 0 healthy dogs weighing > 10 kg (22 lb). PROCEDURE: Dogs were anesthestized with acepromazine, glycopyrrolate, thiopental, and isoflurane, and butorphanol (n = 10) or hydromorphone (10) was used for perioperative analgesia. Arterial blood gas analyses were performed 10 and 30 minutes and 1, 2, 3, and 4 hours after extubation. RESULTS: In dogs that received hydromorphone, mean PaCO2 was significantly higher, compared with the preoperative value, 10 and 30 minutes and 1, 2, and 3 hours after extubation. Mean PaCO2 was significantly higher in dogs given hydromorphone rather than butorphanol 10 and 30 minutes and 1 and 2 hours after extubation. Mean PaO2 was significantly lower, compared with preoperative values, 30 minutes and 1 and 2 hours after extubation in dogs given hydromorphone and 30 minutes after extubation in dogs given butorphanol. Mean PaO2 was significantly lower in dogs given hydromorphone rather than butorphanol 1 hour after extubation. Four dogs had PaO2 < 80 mm Hg 1 or more times after extubation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that administration of hydromorphone to healthy dogs undergoing elective ovariohysterectomy or castration may result in transient increases in PaCO2 postoperatively and that administration of hydromorphone or butorphanol may result in transient decreases in PaO2. However, increases in PaCO2 and decreases in PaO2 were mild, and mean PaCO2 and PaO2 remained within reference limits.     

Comparison between meloxicam and transdermally administered fentanyl for treatment of postoperative pain in dogs undergoing osteotomy of the tibia and fibula and placement of a uniplanar external distraction device

OBJECTIVE: To compare the efficacy of meloxicam administered perioperatively with transdermal administration of fentanyl via a patch placed preoperatively in dogs undergoing orthopedic surgery. DESIGN: Prospective study. ANIMALS: 16 dogs. PROCEDURE: Unilateral or bilateral osteotomy of the tibia and fibula was surgically performed, and a uniplanar external distraction device was placed in each limb. Postoperative pain and lameness were assessed 24, 48, and 72 hours after administration of the first of 3 doses of meloxicam (0.2 mg/kg [0.09 mg/lb], IV, given preoperatively, followed by 0.1 mg/kg [0.045 mg/lb], IV, after 24 hours, and 0.1 mg/kg, PO, after 48 hours) or preoperative placement of a transdermal fentanyl patch (50 microg/h) left in place for 72 hours. RESULTS: No significant differences in total pain scores were detected between groups. Mean +/- SD lameness scores assessed at 24 and 72 hours were lower in dogs in the meloxicam group than dogs in the fentanyl group. Lameness scores decreased with time in a similar manner in both treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Perioperative administration of meloxicam or preoperative placement of a transdermal fentanyl patch provided effective and similar postoperative analgesia in dogs undergoing orthopedic surgery. However, because of its anti-inflammatory effects, treatment with meloxicam reduced the degree of lameness and resulted in rapid functional recovery of the limb.     

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.     

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.     

Effects of continuous rate intravenous infusion of butorphanol on physiologic and outcome variables in horses after celiotomy

A randomized, controlled, blinded clinical trial was performed to determine whether butorphanol administered by continuous rate infusion (CRI) for 24 hours after abdominal surgery would decrease pain and surgical stress responses and improve recovery in horses. Thirty-one horses undergoing exploratory celiotomy for abdominal pain were randomly assigned to receive butorphanol CRI (13 microg/kg/h for 24 hours after surgery; treatment) or isotonic saline (control). All horses received flunixin meglumine (1.1 mg/kg IV q12h). There were no significant differences between treatment and control horses in preoperative or operative variables. Treatment horses had significantly lower plasma cortisol concentration compared with control horses at 2, 8, 12, 24, 36, and 48 hours after surgery. Mean weight loss while hospitalized was significantly less for treatment horses than control horses, whether expressed as total decrease in body weight (13.9+/-3.4 and 27.9+/-4.5 kg, respectively) or as a percentage decrease in body weight (2.6+/-0.7 and 6.3+/-1.1%, respectively). Treatment horses were significantly delayed in time to first passage of feces (median times of 15 and 4 hours, respectively). Treatment horses had significantly improved behavior scores during the first 24 hours after surgery, consistent with the conclusion that they experienced less pain during that time. Butorphanol CRI during the immediate postoperative period significantly decreased plasma cortisol concentrations and improved recovery characteristics in horses undergoing abdominal surgery.     

Comparison of pharmacokinetics of fentanyl after intravenous and transdermal administration in cats

OBJECTIVE: To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats. ANIMALS: 6 healthy adult cats with a mean weight of 3.78 kg. PROCEDURE: Each cat was given fentanyl IV (25 mg/cat; mean +/- SD dosage, 7.19 +/- 1.17 mg/kg of body weight) and via a transdermal patch (25 microg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curve-stripping process followed by nonlinear, least-squares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data. RESULTS: Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 +/- 0.57 hours). Mean +/- SEM calculated rate of transdermal delivery of fentanyl was 8.48 +/- 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steady-state concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.