Epidural analgesia with morphine or buprenorphine in ponies with lipopolysaccharide (LPS)-induced carpal synovitis

This study evaluated the analgesia effects of the epidural administration of 0.1 mg/kg bodyweight (BW) of morphine or 5 μg/kg BW of buprenorphine in ponies with radiocarpal joint synovitis. Six ponies were submitted to 3 epidural treatments: the control group (C) received 0.15 mL/kg BW of a 0.9% sodium chloride (NaCl) solution; group M was administered 0.1 mg/kg BW of morphine; and group B was administered 5 μg/kg BW of buprenorphine, both diluted in 0.9% NaCl to a total volume of 0.15 mL/kg BW administered epidurally at 10 s/mL. The synovitis model was induced by injecting 0.5 ng of lipopolysaccharide (LPS) in the left or right radiocarpal joint. An epidural catheter was later introduced in the lumbosacral space and advanced up to the thoracolumbar level. The treatment started 6 h after synovitis induction. Lameness, maximum angle of carpal flexion, heart rate, systolic arterial pressure, respiratory rate, temperature, and intestinal motility were evaluated before LPS injection (baseline), 6 h after LPS injection (time 0), and 0.5, 1, 2, 4, 6, 8, 10, 12, 16, 20, and 24 h after treatments. Although the model of synovitis produced clear clinical signs of inflammation, the lameness scores in group C were different from the baseline for only up to 12 h. Both morphine and buprenorphine showed a reduction in the degree of lameness starting at 0.5 and 6 h, respectively. Reduced intestinal motility was observed at 0.5 h in group M and at 0.5 to 1 h in group B. Epidural morphine was a more effective analgesic that lasted for more than 12 h and without side effects. It was concluded that morphine would be a valuable analgesic option to alleviate joint pain in the thoracic limbs in ponies.     

Buprenorphine in combination with naloxone at a ratio of 15:1 does not enhance antinociception from buprenorphine in healthy cats

Naloxone can enhance the antinociceptive/analgesic effects of buprenorphine in humans and rats. The antinociceptive effects of a patented 15:1 buprenorphine:naloxone combination was investigated in cats using a thermal and mechanical nociceptive model. Twelve cats received buprenorphine 10 μg/kg, naloxone 0.67 μg/kg or a buprenorphine-naloxone combination intramuscularly in a randomised cross over study. Using thermal and mechanical analgesiometry validated in the cat, pre-treatment baselines were measured. Following test drug administration, thresholds were studied for the next 24h. Naloxone did not enhance the thermal antinociceptive effect of buprenorphine. The results from this study are in agreement with previously published work showing that naloxone antagonises the effects of clinically analgesic doses of buprenorphine. Mechanical nociceptive thresholds were not affected by buprenorphine.     

Effects of acepromazine, butorphanol and buprenorphine on thermal and mechanical nociceptive thresholds in horses

Reasons for performing study: To investigate the antinociceptive effects of buprenorphine administered in combination with acepromazine in horses and to establish an effective dose for use in a clinical environment. Objectives: To evaluate the responses to thermal and mechanical stimulation following administration of 3 doses of buprenorphine compared to positive (butorphanol) and negative (glucose) controls. Methods: Observer blinded, randomised, crossover design using 6 Thoroughbred geldings (3–10 years, 500–560 kg). Thermal and mechanical nociceptive thresholds were measured 3 times at 15 min intervals. Horses then received acepromazine 0.05 mg/kg bwt with one of 5 treatments i.v.: 5% glucose (Glu), butorphanol 100 µg/kg bwt (But) buprenorphine 5 µg/kg bwt (Bup5), buprenorphine 7.5 µg/kg bwt (Bup7.5) and buprenorphine 10 µg/kg bwt (Bup10). Thresholds were measured 15, 30, 45, 60, 90, 120, 150, 180, 230 min, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 24 h post treatment administration. The 95% confidence intervals for threshold temperature (ΔT) for each horse were calculated and an antinociceptive effect defined as ΔT, which was higher than the upper limit of the confidence interval. Duration of thermal antinociception was analysed using a within‐subjects ANOVA and peak mechanical thresholds with a general linear model with post hoc Tukey tests. Significance was set at P<0.05. Results: Mean (± s.d.) durations of thermal antinociception following treatment administration were: Glu 0.5 (1.1), But 2.9 (2.0), Bup5 7.4 (2.3), Bup7.5 7.8 (2.7) and Bup10 9.4 (1.1) h. B5, B7.5 and B10 were significantly different from Glu and But. No serious adverse effects occurred, although determination of mechanical thresholds was confounded by locomotor stimulation. Conclusions: Administration of acepromazine and all doses of buprenorphine produced antinociception to a thermal stimulus for significantly longer than acepromazine and either butorphanol or glucose. Potential relevance: This study suggests that buprenorphine has considerable potential as an analgesic in horses and should be examined further under clinical conditions and by investigation of the pharmacokinetic/pharmacodynamic profile.     

Effects of epidurally administered morphine or buprenorphine on the thermal threshold in cats

Objective: To determine the antinociceptive effects of epidural administration of morphine or buprenorphine in cats by use of a thermal threshold model. ANIMALS: 6 healthy adult cats. PROCEDURES: Baseline thermal threshold was determined in duplicate. Cats were anesthetized with isoflurane in oxygen. Morphine (100 microg/kg diluted with saline [0.9% NaCl] solution to a total volume of 0.3 mL/kg), buprenorphine (12.5 microg/kg diluted with saline solution to a total volume of 0.3 mL/kg), or saline solution (0.3 mL/kg) was administered into the epidural space according to a Latin square design. Thermal threshold was determined at various times up to 24 hours after epidural injection. RESULTS: Epidural administration of saline solution did not affect thermal threshold. Thermal threshold was significantly higher after epidural administration of morphine and buprenorphine, compared with the effect of saline solution, from 1 to 16 hours and 1 to 10 hours, respectively. Maximum (cutout) temperature was reached without the cat reacting in 0, 74, and 11 occasions in the saline solution, morphine, and buprenorphine groups, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of morphine and buprenorphine induced thermal antinociception in cats. At the doses used in this study, the effect of morphine lasted longer and was more intense than that of buprenorphine.     

Thermal antinociception after dexmedetomidine administration in cats: a dose-finding study

The optimum dose of dexmedetomidine for antinociception to a thermal stimulus was determined in a crossover study of 12 cats. In five treatment groups ( n  = 10 per group), dexmedetomidine was administered intramuscularly (i.m.) at 2, 5, 10, 20 and 40 μg/kg; positive and negative controls were administered buprenorphine (20 μg/kg, i.m.) and 0.9% saline (0.006 mL/kg, i.m.) respectively. Baseline thermal thresholds and visual analogue scale (VAS) sedation scores were obtained prior to drug treatment and then at regular intervals until 24 h after administration. The summary measures of overall mean thresholds and overall mean VAS scores were investigated using a univariate general linear model for multiple factors with post hoc Tukey's tests ( P  < 0.05). Only dexmedetomidine at 40 μg/kg displayed an analgesic effect (less than that of buprenorphine). The VAS for sedation did not significantly affect the thresholds obtained and treatment was the only significant factor to influence VAS. Dexmedetomidine resulted in higher VAS for sedation than saline and buprenorphine. Dexmedetomidine at 40 μg/kg significantly increased nociceptive thresholds compared with saline control, but less than buprenorphine. Dexmedetomidine produced dose-dependent sedation, but only the highest dose produced analgesia, suggesting that induction of analgesia requires the highest dose (or an additional analgesic) in the clinical setting.     

Further studies on the antinociceptive activity and respiratory effects of buprenorphine in sheep

The thermal and mechanical analgesic profile of buprenorphine at a dose rate of 1.5 micrograms/kg i.v. was investigated in five sheep. This dose produced significant analgesia for 40 min against the thermal stimulus, but no mechanical antinociception. A higher dose rate of 12 micrograms/kg also failed to produce antinociception to a mechanical stimulus. In addition, the effect of the drug (6 micrograms/kg) on respiratory gas tensions was determined and no significant changes were observed.     

Comparison of Analgesic Effects of Caudal Epidural 0.25% Bupivacaine with Bupivacaine Plus Morphine or Bupivacaine Plus Ketamine for Analgesia in Conscious Horses

The aim of this study was to compare the effects of caudal epidural bupivacaine alone (BP), bupivacaine plus morphine (BPMP), and bupivacaine plus ketamine (BPKE) for perineal analgesia in horses. Each of the six saddle horses received a caudal epidural catheter and underwent 3 treatments: BP, 0.25% (0.04 mg/kg) bupivacaine hydrochloride without epinephrine; BPMP, 0.02 mg/kg of bupivacaine combined with 0.1 mg/kg of morphine-preservative free; and BPKE, 0.02 mg/kg of bupivacaine combined with 0.5 mg/kg of ketamine. The order of treatments was randomized. The cardiovascular system, respiratory rate, quality of analgesia, sedation, and motor blockade were assessed before drug administration (baseline), at 5, 10, 15, and 30 minutes, and every 30 minutes thereafter until loss of analgesia. The median time to onset of analgesia was 5 minutes after BP treatment, faster than after BPKE or BPMP treatments, which were 10 minutes and 15 minutes, respectively (P < .05). The BPMP treatment produced analgesia (315 minutes) for a longer duration than BP treatment (210 minutes) or BPKE treatment (240 minutes), in the regions of the tail, perineum, and upper hind limb in horses. All treatments presented mild sedation or motor blockade. There were minimal effects on the cardiovascular system and respiratory rate. BPMP may be preferable to a high dose of BP or BPKE. Caudal epidural BPMP can be an appropriate choice for regional perineal analgesia in horses.     

Bovine Chlamydophila spp. infection: Do we underestimate the impact on fertility?

The efficacy of ketamine and bupivacaine in enhancing the epidural analgesia induced by medetomidine was evaluated in 10 buffalo calves utilized repeatedly after a gap of 10 days so that each drug combination was tested in 4 randomly selected animals. In group A, medetomidine (15 microg/kg), in group B ketamine (2.0 mg/kg), in group C bupivacaine (0.125 mg/kg), in group D medetomidine and ketamine (15 microg/kg and 2.0 mg/kg), and in group E medetomidine and bupivacaine (15 microg/kg and 0.125 mg/kg) was administered epidurally. Onset of analgesia was significantly earlier in animals of groups B and D compared to the animals of groups A, C and E. Medetomidine alone or in combination with ketamine/bupivacaine produced complete analgesia of the tail, perineum, inguinal region and upper parts of hind limbs. Ketamine produced a very short duration of complete analgesia at the tail and perineum. Bupivacaine alone produced only mild to moderate analgesia. Both ketamine and bupivacaine prolonged the duration of analgesia. Motor incoordination was mild to moderate in animals of all the groups, but animals remained standing throughout the period of observation. Animals of groups A, D and E showed mild to moderate sedation during the observation period. Ruminal movements decreased nonsignificantly in animals of groups A and E. Mild salivation was observed in animals of all the groups except group C. Significant decrease in heart rate (HR) was recorded after epidural administration of medetomidine or bupivacaine; however, ketamine caused short duration of tachycardia. The administration of ketamine with medetomidine caused lesser decrease in HR compared to medetomidine alone or in combination with bupivacaine. Significant fall in respiratory rate (RR) was recorded after epidural administration of medetomidine or bupivacaine alone, but an increase in RR was recorded after ketamine administration. The fall in RR was less pronounced in animals in which medetomidine was used with ketamine compared to the animals in which medetomidine was used alone or in combination with bupivacaine. Mean arterial pressure (MAP) decreased and central venous pressure (CVP) increased significantly after epidural administration of medetomidine in combination with ketamine or bupivacaine. The ECG changes included tall T wave, QS pattern, RS pattern and ST elevation and heart blocks at different intervals, which were more frequent and pronounced in animals given bupivacaine with medetomidine. It can be concluded that epidural administration of medetomidine can produce complete analgesia of the tail, perineum, inguinal region and upper hind limbs in buffaloes. However, significant depression of cardiovascular parameters was recorded. Administration of ketamine along with medetomidine resulted in significantly early onset and slightly longer duration of analgesia with lesser cardiopulmonary side-effects compared to medetomidine alone or medetomidine with bupivacaine. Addition of ketamine to medetomidine thus seems to be useful for producing epidural analgesia; however, addition of bupivacaine failed to provide any advantage over medetomidine alone.     

Combination of dexmedetomidine with buprenorphine enhances the antinociceptive effect to a thermal stimulus in the cat compared with either agent alone

ObjectiveTo evaluate the sedative and antinociceptive effects of combinations of dexmedetomidine and buprenorphine in cats.Study designExperimental randomized study.AnimalsTwelve purpose-bred neutered domestic short-hair cats (4 male and 8 female) weighing 4.6 kg (range 3.7–5.5 kg) aged from 2 to 5 years.MethodsSix cats per group were administered buprenorphine (B) at 10 (B10) or 20 μg kg^?1 (B20) or dexmedetomidine (D) at 20 (D20) or 40 μg kg^?1 (D40) or a combination of B10/D20. A feline thermal nociceptive threshold testing device was used to evaluate the antinociceptive effects of the drugs before and up to 24 hours after drug treatment. Sedation was scored using a 100 mm visual analogue scale (VAS).ResultsThermal thresholds increased significantly after administration of all but D20. Area under the curve (AUC, hours °C) for the first 6 hours (mean ± SD) for B20 (281 ± 17.8) was significantly greater than B10 (260 ± 11.4), D20 (250 ± 7.9) and D40 (255 ± 11.4). The AUC for B10/D20 (273 ± 12.2) was significantly greater than D20 but not the other treatments. No sedation was seen after administration of B10 or B20 and maximal sedation was seen for all animals in the D40 and B10/D20 groups and most animals in the D20 group.ConclusionsD20 alone had the smallest analgesic effect; B10 alone provided no sedation but their combination gave good sedation with analgesia comparable with B20.Clinical relevanceThis combination could be a useful multimodal sedative/analgesic regimen in cats.     

Sedative effects of medetomidine in pigs.

Sedative effects of medetomidine, a potent selective and specific alpha 2-adrenoceptor agonist, were evaluated in pigs using 5 different doses (30, 50, 80, 100 and 150 micrograms/kg of body weight) and compared with those of xylazine (2 mg/kg). Atropine (25 micrograms/kg) was mixed with both drugs to prevent severe bradycardia. All drugs were administered intramuscularly. Medetomidine at a dosage of 30 micrograms/kg produced more potent sedation than xylazine. The depth of sedation induced by medetomidine was dose dependent within the range from 30 to 80 micrograms/kg. At 100 or 150 micrograms/kg, the depth of sedation was mostly the similar level to that at 80 micrograms/kg but the duration was prolonged. The degree of muscle relaxation produced by medetomidine also seemed to be dose dependent from 30 to 80 micrograms/kg and was stronger than that produced by xylazine. An increase in the duration of muscle relaxation was dose dependent up to 150 micrograms/kg. No analgesic effect was produced by xylazine, however moderate analgesia was obtained by medetomidine. There were no marked changes in heart rate and respiratory rate during the observation period in pigs of any groups, however mild hypothermia after the administration of both drugs was observed. From these results, medetomidine has a significant and dose-dependent sedative effects which are much more potent than that of xylazine, and a combination of 80 micrograms/kg of medetomidine and 25 micrograms/kg of atropine is suitable for sedation with lateral recumbency and moderate muscle relaxation without notable side effects in pigs.     

Pharmacokinetics of the opioid antagonist N-methylnaltrexone and evaluation of its effects on gastrointestinal tract function in horses treated or not treated with morphine

OBJECTIVE: To determine the pharmacokinetics and effects of the morphine antagonist N-methylnaltrexone (MNTX) on gastrointestinal tract function in horses when administered alone and in combination with morphine. ANIMALS: 5 healthy adult horses. PROCEDURES: Horses were treated with MNTX (1 mg/kg, IV), and serial blood samples were collected for determination of drug pharmacokinetics. For evaluation of effects on the gastrointestinal tract when administered alone, MNTX was administered at a dosage of 0.75 mg/kg, IV, twice daily for 4 days. For evaluation of effects when administered concurrently with morphine, MNTX (0.75 mg/kg, IV, q 12 hours) and morphine (0.5 mg/kg, IV, q 12 hours) were administered for 6 days. Gastrointestinal variables evaluated were defecation frequency, weight of feces produced, fecal moisture content, intestinal transit time, and borborygmus scores. RESULTS: The time-concentration data for MNTX disposition best fit a 2-compartment model with a steady-state volume of distribution of 244.6 +/- 21.8 mL/kg, t1/2 of 47.04 +/- 11.65 minutes, and clearance of 11.43 +/- 1.06 mL/min/kg. Adverse effects were not observed at doses 相似文献   

Cardiorespiratory effects of epidural administration of morphine and fentanyl in dogs anesthetized with sevoflurane

OBJECTIVE: To determine the cardiorespiratory effects of epidural administration of morphine alone and in combination with fentanyl in dogs anesthetized with sevoflurane. DESIGN: Prospective study. ANIMALS: 6 dogs. PROCEDURE: Dogs were anesthetized with sevoflurane and allowed to breathe spontaneously. After a stable plane of anesthesia was achieved, morphine (0.1 mg/kg [0.045 mg/lb]) or a combination of morphine and fentanyl (10 microg/kg [4.5 microg/lb]) was administered through an epidural catheter, the tip of which was positioned at the level of L6 or L7. Cardiorespiratory variables were measured for 90 minutes. RESULTS: Epidural administration of morphine alone did not cause any significant changes in cardiorespiratory measurements. However, epidural administration of morphine and fentanyl induced significant decreases in diastolic and mean arterial blood pressures and total peripheral resistance. Stroke volume was unchanged, PaCO2 was significantly increased, and arterial pH and base excess were significantly decreased. Heart rate was significantly lower after epidural administration of morphine and fentanyl than after administration of morphine alone. None of the dogs had any evidence of urine retention, vomiting, or pruritus after recovery from anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that epidural administration of morphine at a dose of 0.1 mg/kg in combination with fentanyl at a dose of 10 microg/kg can cause cardiorespiratory depression in dogs anesthetized with sevoflurane.     

A comparison of preoperative morphine and buprenorphine for postoperative analgesia for arthrotomy in dogs

The aim of this study was to compare morphine with the partial agonist, buprenorphine, for postoperative analgesic effects, when administered preoperatively for elective arthrotomy in dogs. Fifty two dogs were anaesthetized for stifle, elbow, or hock arthrotomy. The dogs were premedicated 30 min prior to induction of anaesthesia with 0.03 mg/kg acepromazine intramuscularly, and either 0.3 mg/kg morphine or 0.01 mg/kg buprenorphine intramuscularly (allocated randomly). Anaesthesia was induced with thiopentone and maintained with halothane in an oxygen/nitrous oxide mixture. Pain and sedation were assessed preoperatively, and 0.5, 1, 2, 3, 5, and 7 h after the halothane was switched off, with a visual analogue scale scoring system. Pain scores did not differ significantly (morphine group median postoperative score from 30 to 40 mm, buprenophine group median postoperative score from 36 to 43 mm) and analgesia was considered adequate in the majority of cases (score less than 40 mm). Morphine produced significantly more sedation at 0.5 h after anaesthesia only. It was concluded that both opioids are equally suitable analgesics for postoperative analgesia for the elective arthrotomy in dogs.     

Combined use of detomidine with opiates in the horse

The effects of administration of one of four opiates (pethidine 1 mg/kg bodyweight (bwt), morphine 0.1 mg/kg bwt, methadone 0.1 mg/kg bwt, and butorphanol 0.05 mg/kg bwt) given intravenously to horses and ponies already sedated with detomidine (10 micrograms/kg bwt) were investigated. Behavioural, cardiovascular and respiratory effects of the combinations were compared with those occurring with detomidine alone. Addition of the opiate increased the apparent sedation and decreased the response of the animal to external stimuli. At doses used, butorphanol produced the most reliable response. Side effects seen were increased ataxia (greatest following methadone and butorphanol) and excitement (usually muzzle tremors and muscle twitching). Following pethidine, generalised excitement was sometimes seen. Marked cardiovascular changes occurred in the first few minutes after morphine or pethidine injection, but within 5 mins cardiovascular changes were minimal. Following morphine or pethidine there was a significant increase in arterial carbon dioxide tension. Fourteen clinical cases were successfully sedated using detomidine/butorphanol combinations.     

Dexmedetomidine and Bupivacaine Association in Caudal Epidural Injection in Mares

The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330–370 kg and aged 10–15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 μg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 μg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidural injections, heart rate, respiratory rate, arterial blood pressures (systolic, diastolic, and mean), and rectal temperature were measured at 5, 10, 15, 30, 60, 90, and 120 minutes, and after this time, every 60 minutes until the end of the experiments. A subjective score system was used to assess analgesia, behavioral and motor blockade at the same time points. The BPDX treatment produced analgesic action with twice the duration (200 minutes) of the BP treatment (97 minutes), but with an analgesic duration shorter than the DX treatment (240 minutes) in the regions of the tail, perineum, and upper hind limbs in mares. All treatments showed mild motor blockade. No behavioral changes were observed in any of the animals. There was hemodynamic stability without significant changes in respiratory rate for all treatments. Epidural analgesia using DEX alone or the combination of DEX and bupivacaine may be an option for painful obstetric and gynecological procedures in mares.     

Postoperative Analgesia for Stifle Surgery: A Comparison of Intra-articular Bupivacaine, Morphine, or Saline

A prospective study was undertaken to compare the analgesic effect of intra-articular bupivacaine, morphine, or saline in the 24-hour period following cranial cruciate ligament repair in dogs. Thirty-six clinical patients with ruptured cranial cruciate ligaments were randomly assigned to one of three groups. After surgical stabilization, and before skin closure, an intra-articular injection was given; group one (n = 12) received 0.5% bupivacaine HCl at 0.5 mL/kg, group two (n = 12) received morphine at 0.1 mg/kg diluted with saline to a volume of 0.5 mL/kg, and group three (n = 12) received saline at 0.5 mL/kg. Heart rate, respiratory rate, mean arterial blood pressure, cumulative pain score, visual analog pain score, and pain threshold test on both stifles were recorded preoperatively and at 0 to 6 and 24 hours postoperatively. Surgeons and pain scoring investigators were unaware of the intra-articular medication given. Supplemental analgesia, if needed, was provided in the postoperative period according to subjective assessment of patient discomfort. Postoperative pain scores were lowest in the bupivacaine group and highest in the saline group. Pain threshold, measured by applying calibrated loads to the knee, was higher postoperatively in the bupivacaine group than in the saline group. Dogs in the morphine and bupivacaine groups required less supplemental analgesia than dogs in the saline group. The local provision of analgesia reduces the need for systemic drugs with potential side effects. Both intra-articular morphine and intra-articular bupivacaine provided better postoperative analgesia than intra-articular saline, with intra-articular bupivacaine showing the greatest effect.     

Comparative analgesic and sedative effects of tramadol,tramadol‐lidocaine and lidocaine for caudal epidural analgesia in donkeys (Equus asinus)

ObjectiveTo compare anti-nociceptive and sedative effects of tramadol, a combination of tramadol-lidocaine, and lidocaine alone for perineal analgesia in donkeys.Study designExperimental ‘blinded’ randomized cross-over study.AnimalsSix healthy adult donkeys.MethodsTreatments were tramadol (TR) (1.0 mg kg⁻¹), tramadol-lidocaine (TRLD) (0.5 and 0.2 mg kg⁻¹ respectively) and lidocaine (LD) (0.4 mg kg⁻¹) given into the epidural space. The volume of all treatments was 0.02 mL kg⁻¹. Nociception was tested at the perineal region by pin prick, followed, if no reaction, by pressure from a haemostat clamp. Times to onset, degree and duration of anti-nociception of the perineal region were recorded. Response was tested immediately after drug administration and at: 2, 5, 10, 15, 30, 45, and 60 minutes post-administration and then at 30 minute intervals thereafter until a response re-occurred. Physiologic data and degree of sedation and ataxia were recorded pre-administration and at intervals for 240 minutes post-administration. Results were analyzed using anova, Kruskal–Wallis tests, and Wilks’ Lambda test as relevant. Significance was taken as p < 0.05.ResultsTimes (minutes, mean ± SD) to onset and duration of anti-nociception, respectively were; TR 13 ± 1.6 and 220 ± 4.6; TRLD 6 ± 0.8 and 180 ± 8.5; LD 4 ± 1.4 and 75 ± 4. Onset and duration times were significantly longer with TR than the other two treatments. TR never produced complete anti-nociception, whereas the TRLD and LD induced complete anti-nociceptive effects. Duration was significantly longer with TRLD than with LD alone. Epidural injections of TR and TRLD induced mild sedation.Conclusions and clinical relevanceEpidural combination of TRLD produced an anti-nociceptive effect in the perineum, which was rapid in onset and had a longer duration of action than LD alone. An epidural single dose of TRLD combination would appear to provide an acceptable analgesic effect in the perineal region of donkeys.     

Evaluation of detomidine as a sedative in goats.

Intramuscular (i.m.) and intravenous (i.v.) administration of detomidine at doses of 10, 20 and 40 micrograms/kg body mass was evaluated for its sedative and analgesic properties in 15 goats (Capra hircus). The drug produced dose- and route-dependent sedation. The 10 micrograms/kg dose was effective only when administered i.v. There was no observable analgesia at this dose. Higher doses produced effective sedation and moderate analgesia of the body with either route of administration. Severe ataxia and sternal recumbency were seen in all the animals after the dose of 40 micrograms/kg. Other effects of detomidine in these goats included mild to moderate salivation, depressed respiratory rate, decreased rectal temperature, bradycardia and hyperglycaemia. Plasma concentrations of total protein, sodium, potassium and chloride were not affected.     

Effects of morphine,butorphanol, buprenorphine,and U50488H on the minimum alveolar concentration of isoflurane in cats

OBJECTIVE: To determine whether opioids with varying interactions at receptors induce a reduction in minimum alveolar concentration (MAC) of isoflurane in cats. ANIMALS: 12 healthy, female, spayed cats. PROCEDURE: Cats were anesthetized with isoflurane and instrumented to allow collection of arterial blood and measurement of arterial blood pressure. Each drug was studied separately, and for each drug cats were randomly allocated to receive 2 doses. The drugs studied were morphine (0.1 or 1.0 mg/kg), butorphanol (0.08 or 0.8 mg/kg), buprenorphine (0.005 and 0.05 mg/kg), and U50488H (0.02 and 0.2 mg/kg). All drugs were diluted in 5 ml of saline (0.9% NaCl) solution and infused IV for 5 minutes. The MAC of isoflurane was determined in triplicate, the drug administered, and the MAC of isoflurane redetermined for a period of 3 hours. RESULTS: All drugs had a significant effect on MAC over time. With morphine only, the effect on MAC over time was different between doses. The greatest mean (+/- SD) reductions in MAC of isoflurane in response to morphine, butorphanol, buprenorphine, and U50488H administration were 28 +/- 9, 19 +/- 3, 14 +/- 7, and 11 +/- 7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Morphine (1.0 mg/kg) and butorphanol (0.08 and 0.8 mg/kg) induced significant reductions in MAC of isoflurane that were considered clinically important. Although significant, reductions in MAC of isoflurane induced by morphine (0.1 mg/kg), buprenorphine (0.005 and 0.05 mg/kg), and U50488H (0.02 and 0.2 mg/kg) were not considered clinically relevant because they fell within the error of the measurement technique. Administration of morphine or butorphanol decreases the need for potent inhalant anesthetics in cats and could potentially be beneficial in combination with inhalants.     

Effects of epidural administration of morphine and buprenorphine on the minimum alveolar concentration of isoflurane in cats

OBJECTIVE: To determine effects of epidural administration of morphine and buprenorphine on the minimum alveolar concentration of isoflurane in cats. Animals-6 healthy adult domestic shorthair cats. PROCEDURES: Cats were anesthetized with isoflurane in oxygen. Morphine (100 microg/kg diluted with saline [0.9% NaCl] solution to a volume of 0.3 mL/kg), buprenorphine (12.5 microg/kg diluted with saline solution to a volume of 0.3 mL/kg), or saline solution (0.3 mL/kg) was administered into the epidural space according to a Latin square design. The minimum alveolar concentration (MAC) of isoflurane was measured in triplicate by use of the tail clamp technique. At least 1 week was allowed between successive experiments. RESULTS: The MAC of isoflurane was 2.00 +/- 0.18%, 2.13 +/- 0.11%, and 2.03 +/- 0.09% in the morphine, buprenorphine, and saline solution groups, respectively. No significant difference in MAC was detected among treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: A significant effect of epidural administration of morphine or buprenorphine on the MAC of isoflurane in cats could not be detected. Further studies are needed to establish whether epidural opioid administration has other benefits when administered as a component of general anesthesia in cats.