Effects of butorphanol on the minimum anesthetic concentration for sevoflurane in guineafowl (Numida meleagris)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparative study on the sedative effects of morphine, methadone, butorphanol or tramadol, in combination with acepromazine, in dogs

To compare the effects of morphine (MOR), methadone (MET), butorphanol (BUT) and tramadol (TRA), in combination with acepromazine, on sedation, cardiorespiratory variables, body temperature and incidence of emesis in dogs.Prospective randomized, blinded, experimental trial.Six adult mixed-breed male dogs weighing 12.0 +/- 4.3 kg.Dogs received intravenous administration (IV) of acepromazine (0.05 mg kg(-1)) and 15 minutes later, one of four opioids was randomly administered IV in a cross-over design, with at least 1-week intervals. Dogs then received MOR 0.5 mg kg(-1); MET 0.5 mg kg(-1); BUT 0.15 mg kg(-1); or TRA 2.0 mg kg(-1). Indirect systolic arterial pressure (SAP), heart rate (HR), respiratory rate (f(R)), rectal temperature, pedal withdrawal reflex and sedation were evaluated at regular intervals for 90 minutes.Acepromazine administration decreased SAP, HR and temperature and produced mild sedation. All opioids further decreased temperature and MOR, BUT and TRA were associated with further decreases in HR. Tramadol decreased SAP whereas BUT decreased f(R) compared with values before opioid administration. Retching was observed in five of six dogs and vomiting occurred in one dog in MOR, but not in any dog in the remaining treatments. Sedation scores were greater in MET followed by MOR and BUT. Tramadol was associated with minor changes in sedation produced by acepromazine alone.When used with acepromazine, MET appears to provide better sedation than MOR, BUT and TRA. If vomiting is to be avoided, MET, BUT and TRA may be better options than MOR.

Post-operative analgesic effects of butorphanol or firocoxib administered to dogs undergoing elective ovariohysterectomy

ObjectiveTo compare the post-operative analgesic effects of butorphanol or firocoxib in dogs undergoing ovariohysterectomy.Study designProspective, randomized, blinded, clinical trial.AnimalsTwenty-five dogs > 1 year of age.MethodsDogs received acepromazine intramuscularly (IM), 0.05 mg kg-1 and either butorphanol IM, 0.2 mg kg-1 (BG, n = 12) or firocoxib orally (PO), 5 mg kg-1 (FG, n = 13), approximately 30 minutes before induction of anesthesia with propofol. Anesthesia was maintained with isoflurane. Ovariohysterectomy was performed by the same surgeon. Pain scores using the dynamic and interactive visual analog scale (DIVAS) were performed before and at 1, 2, 3, 4, 6, 8 and 20 hours after the end of surgery by one observer, blinded to the treatment. Rescue analgesia was provided with morphine (0.5 mg kg-1) IM and firocoxib, 5 mg kg-1 (BG only) PO if DIVAS > 50. Groups were compared using paired t-tests and Fisher's exact test (p < 0.05). Data are presented as mean +/- SD.ResultsThe BG required significantly less propofol (BG: 2.6 +/- 0.59 mg kg-1; FG: 5.39 +/- 0.7 mg kg-1) (p < 0.05) but the anesthesia time was longer (BG: 14 +/- 6, FG: 10 +/- 4 minutes). There were no differences for body weight (BG: 7.9 +/- 5.0, FG: 11.5 +/- 4.6 kg), sedation scores, and surgery and extubation times (BG: 10 +/- 2, 8 +/- 5 minutes; FG: 9 +/- 3, 8 +/- 4 minutes, respectively) (p > 0.05). The FG had significantly lower pain scores than the BG at 1, 2 and 3 hours following surgery (p < 0.05). Rescue analgesia was administered to 11/12 (92%) and 2/13 (15%) dogs in the BG and FG, respectively (p < 0.05).Conclusion and clinical relevanceFirocoxib produced better post-operative analgesia than butorphanol. Firocoxib may be used as part of a multimodal analgesia protocol but may not be effective as a sole analgesic.

Hemodynamic effects of butorphanol in desflurane-anesthetized dogs

Objective To evaluate the effects of butorphanol on cardiopulmonary parameters in dogs anesthetized with desflurane and breathing spontaneously.Study design Prospective, randomized experimental trial.Animals Twenty dogs weighing 12 +/- 3 kg.Methods Animals were distributed into two groups: a control group (CG) and butorphanol group (BG). Propofol was used for induction and anesthesia was maintained with desflurane (10%). Forty minutes after induction, the dogs in the CG received sodium chloride 0.9% (0.05 mL kg(-1) IM), and dogs in the BG received butorphanol (0.4 mg kg(-1) IM). The first measurements of body temperature (BT), heart rate (HR), arterial pressures (AP), cardiac output (CO), cardiac index (CI), central venous pressure (CVP), stroke volume index (SVI), pulmonary arterial occlusion pressure (PAOP), mean pulmonary arterial pressure (mPAP), left ventricular stroke work (LVSW), systemic (SVR) and pulmonary (PVR) vascular resistances, respiratory rate (fR), and arterial oxygen (PaO(2)) and carbon dioxide (PaCO(2)) partial pressures were taken immediately before the administration of butorphanol or sodium chloride solution (T0) and then at 15-minute intervals (T15-T75).Results In the BG, HR, AP, mPAP and SVR decreased significantly from T15 to T75 compared to baseline. fR was lower at T30 than at T0 in the BG. AP and fR were significantly lower than in the CG from T15 to T75. PVR was lower in the BG than in the CG at T30, while PaCO(2) was higher compared with T0 from T30 to T75 in the BG and significantly higher than in the CG at T30 to T75.Conclusions and clinical relevance At the studied dose, butorphanol caused hypotension and decreased ventilation during desflurane anesthesia in dogs. The hypotension (from 86 +/- 10 to 64 +/- 10 mmHg) is clinically relevant, despite the maintenance of cardiac index.

Behavioral and Antinociceptive Effects of Alfentanil, Butorphanol, and Flunixin in Horses

To determine the behavioral and antinociceptive effects of narcotic and non-narcotic analgesics administered by intravenous injection in horses, 10 thoroughbred mares weighing between 450 and 550 kg and ranging in age from 8 to 13 years old were analyzed. The effects of alfentanil, butorphanol, flunixin, and saline solution on the general activity of the horses were investigated by measuring spontaneous locomotor activity (SLA) and head height (HH) in two behavior stalls. The antinociceptive effects of alfentanil (0.02 mg kg-1), butorphanol (0.1 mg kg-1), flunixin meglumine (0.5 mg kg-1), and saline were determined by measuring skin twitch reflex latency (STRL) after thermal cutaneous nociceptive stimulation. A paired Student t-test was used to compare SLA and HH between the groups of horses receiving different doses of the same drug at various time points. The Tukey test was used to compare the antinociceptive effect of the treatments. Differences were considered significant when P value was <.05. Horses treated with opioid analgesics demonstrated excitation, as shown by a significant increase in SLA at all doses tested and by neighing and demonstrating attentive attitudes with movement of the ears, stereotypical walking, and ataxia in most of the animals. HH was elevated only in animals treated with alfentanil. Antinociception was observed at 5 and 30 minutes after administration of alfentanil and butorphanol, respectively. Increased SLA was observed at 30 and 90 minutes after administration of alfentanil and butorphanol, respectively. We observed no effect on antinociception in horses given flunixin. In conclusion, this study suggests that alfentanil has a faster onset and a shorter duration than butorphanol; however, both drugs are able to stimulate the central nervous system. © 2013 Elsevier Inc. All rights reserved.

Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves

PURPOSE:To assess the hemodynamic changes and bispectral index (BIS) following administration of a continuous rate infusion (CRI) of butorphanol in isoflurane-anesthetized calves.METHODS: Eight calves weighing 110 ± 12 kg were included in the study. Anesthesia was induced with 5% isoflurane in O2 delivered via face mask and maintained with end-tidal concentration of 1.4%. IPPV was set to a peak inspiratory airway pressure of 15 cmH2O and respiratory rate of six breaths minute-1. Forty minutes after the start of anesthetic maintenance, 0.1 mg kg-1butorphanol was administered intravenously, followed by a CRI of 20 µg kg-1 minute-1. Hemodynamic variables and BIS were recorded before butorphanol administration (T0), and at 10, 20, 40 and 80 minutes following the CRI. Anesthesia was discontinued after the last recording and the calves were allowed to recover. The time to sternal recumbency (SRE) and standing (ST) were evaluated.RESULTS: There were no significant differences between the moments in all hemodynamic variables and BIS. The time to SRE and ST was 9 ± 5 and 14 ± 7 minutes, respectively.CONCLUSION: The continuous rate infusion did not produce clinically relevant changes in hemodynamic or bispectral index values compared to baseline in mechanically ventilated and unstimulated calves anesthetized at 1.4% isoflurane.

Cardiopulmonary effects of butorphanol in sevoflurane-anesthetized guineafowl (Numida meleagris)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of a continuous rate infusion of butorphanol in isoflurane-anesthetized horses on cardiorespiratory parameters, recovery quality, gastrointestinal motility and serum cortisol concentrations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of butorphanol on the withdrawal reflex using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses

OBJECTIVE: To assess the effects of a single intravenous dose of butorphanol (0.1 mg kg(-1)) on the nociceptive withdrawal reflex (NWR) using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses. STUDY DESIGN: 'Unblinded', prospective experimental study. ANIMALS: Ten adult horses, five geldings and five mares, mean body mass 517 kg (range 487-569 kg). METHODS: The NWR was elicited using single transcutaneous electrical stimulation of the palmar digital nerve. Repeated stimulations were applied to evoke temporal summation. Surface electromyography was performed to record and quantify the responses of the common digital extensor muscle to stimulation and behavioural reactions were scored. Before butorphanol administration and at fixed time points up to 2 hours after injection, baseline threshold intensities for NWR and temporal summation were defined and single suprathreshold stimulations applied. Friedman repeated-measures analysis of variance on ranks and Wilcoxon signed-rank test were used with the Student-Newman-Keul's method applied post-hoc. The level of significance (alpha) was set at 0.05. RESULTS: Butorphanol did not modify either the thresholds for NWR and temporal summation or the reaction scores, but the difference between suprathreshold and threshold reflex amplitudes was reduced when single stimulation was applied. Upon repeated stimulation after butorphanol administration, a significant decrease in the relative amplitude was calculated for both the 30-80 and the 80-200 millisecond intervals after each stimulus, and for the whole post-stimulation interval in the right thoracic limb. In the left thoracic limb a decrease in the relative amplitude was found only in the 30-80 millisecond epoch. CONCLUSION: Butorphanol at 0.1 mg kg(-1) has no direct action on spinal Adelta nociceptive activity but may have some supraspinal effects that reduce the gain of the nociceptive system. CLINICAL RELEVANCE: Butorphanol has minimal effect on sharp immediate Adelta-mediated pain but may alter spinal processing and decrease the delayed sensations of pain.

Effect of carprofen, etodolac, meloxicam, or butorphanol in dogs with induced acute synovitis

OBJECTIVE: To compare the analgesic and anti-inflammatory effect of single doses of carprofen, etodolac, meloxicam, and butorphanol in dogs with induced acute synovitis (acute pain model) via kinetic gait analysis and orthopedic evaluation and examine measurement of serum C-reactive protein (CRP) concentration as an indicator of treatment efficacy. ANIMALS: 12 Beagles and 6 additional Beagles that were used only in serum CRP analyses. PROCEDURE: Acute synovitis was induced in right stifle joints of dogs via intra-articular injection of monosodium urate solution. Treatments included butorphanol (0.2 mg/kg, i.v.), carprofen (4 mg/kg, PO), etodolac (17 mg/kg, PO), or meloxicam (0.2 mg/kg, PO); control dogs received no treatment. The procedure was repeated (3-week intervals) until all dogs received all treatments including control treatment. Lameness was assessed on a biomechanical force platform and via orthopedic evaluations of the stifle joints; blood was collected to monitor serum CRP concentration. RESULTS: Compared with control dogs, treated dogs had significantly different vertical ground reaction forces and weight-bearing scores. Greatest improvement in lameness was observed in carprofen-treated dogs. Etodolac had the fastest onset of action. Compared with butorphanol treatment, only carprofen and etodolac were associated with significantly lower pain scores. An increase in serum CRP concentration was detected after intra-articular injection in all dogs; this change was similar among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Carprofen, etodolac, and meloxicam had greater efficacy than butorphanol in relief of acute pain. Carprofen was most effective overall. In this acute pain model, serum CRP analysis was not useful to assess drug efficacy.

Combinations of dexmedetomidine and alfaxalone with butorphanol in cats: application of an innovative stepwise optimisation method to identify optimal clinical doses for intramuscular anaesthesia

OBJECTIVES The aim of this study was to optimise dexmedetomidine and alfaxalone dosing, for intramuscular administration with butorphanol, to perform minor surgeries in cats. METHODS Initially, cats were assigned to one of five groups, each composed of six animals and receiving, in addition to 0.3 mg/kg butorphanol intramuscularly, one of the following: (A) 0.005 mg/kg dexmedetomidine, 2 mg/kg alfaxalone; (B) 0.008 mg/kg dexmedetomidine, 1.5 mg/kg alfaxalone; (C) 0.012 mg/kg dexmedetomidine, 1 mg/kg alfaxalone; (D) 0.005 mg/kg dexmedetomidine, 1 mg/kg alfaxalone; and (E) 0.012 mg/kg dexmedetomidine, 2 mg/kg alfaxalone. Thereafter, a modified 'direct search' method, conducted in a stepwise manner, was used to optimise drug dosing. The quality of anaesthesia was evaluated on the basis of composite scores (one for anaesthesia and one for recovery), visual analogue scales and the propofol requirement to suppress spontaneous movements. The medians or means of these variables were used to rank the treatments; 'unsatisfactory' and 'promising' combinations were identified to calculate, through the equation first described by Berenbaum in 1990, new dexmedetomidine and alfaxalone doses to be tested in the next step. At each step, five combinations (one new plus the best previous four) were tested. RESULTS None of the tested combinations resulted in adverse effects. Four steps and 120 animals were necessary to identify the optimal drug combination (0.014 mg/kg dexmedetomidine, 2.5 mg/kg alfaxalone and 0.3 mg/kg butorphanol). CONCLUSIONS AND RELEVANCE The investigated drug mixture, at the doses found with the optimisation method, is suitable for cats undergoing minor clinical procedures.

Alfaxalone-butorphanol versus alfaxalone-morphine combination for immersion anaesthesia in oriental fire-bellied toads (Bombina orientalis)

Oriental fire-bellied toads (Bombina orientalis) are small semi-aquatic anuran species popular as both pets and laboratory animals. Although they are commonly anaesthetized to undergo clinical and experimental procedures, very little is known about their anaesthetic management. The aims of this prospective, randomized, cross-over experimental trial were to establish effective butorphanol and morphine concentrations to be added to alfaxalone for immersion anaesthesia (pilot study), and to compare the anaesthetic and antinociceptive effects of the two drug mixtures (alfaxalone-butorphanol and alfaxalone-morphine), in Bombina orientalis toads. For the actual trial, the toads were randomly assigned to one of two treatment groups: AB and AM, with seven animals in each group, which received alfaxalone-butorphanol and alfaxalone-morphine combinations, respectively, at the concentrations established during the pilot study. Heart rate, respiratory rate, von Frey filament threshold and response to nociceptive withdrawal (NWR), righting and myotactic reflexes were measured at 5 min intervals until return of righting reflex was observed. The investigator who carried out all the measurements was blinded to the treatment. Any undesired effect or complication was noted and recorded. The two treatments were found to be comparable in terms of onset and duration of anaesthesia, and occurrence of undesired effects. However, group AM resulted in lower NWR scores and higher von Frey filament thresholds than group AB. It is concluded that, at the investigated concentrations and in combination with alfaxalone by immersion, morphine provides better antinociception than butorphanol in oriental fire-bellied toads.

Alfaxalone-butorphanol-dexmedetomidine anaesthesia in striped skunks (Mephitis mephitis ) undergoing skin biopsy: two cases

Skunks are becoming increasingly popular as pets. As such, they often undergo a variety of surgical procedures. Two pet skunks undergoing a dermatological examination, including skin biopsy, were anaesthetised with a combination of dexmedetomidine (0.02 mg/kg), butorphanol (0.3 mg/kg), and alfaxalone (4 mg/kg), all administered intramuscularly. Anaesthesia was characterised by rapid onset, absence of detectable side effects and fast recovery after atipamezole administration. Biopsies and toe-pinch did not elicit cardiorespiratory responses, nor did it result in movements or lightening of the anaesthetic depth. Both skunks recovered uneventfully, and showed normal appetite and regular defecation within eight hours following surgery. However, both the animals experienced mild hypothermia at recovery. The dexmedetomidine-alfaxalone-butorphanol combination produced satisfactory anaesthesia in the two skunks, object of this report. This anaesthetic protocol may be used in this species to provide immobility, myorelaxation, unconsciousness and analgesia during skin biopsy or other minor surgical procedures.