Comparison of bupivacaine liposome injectable solution and fentanyl for postoperative analgesia in dogs undergoing limb amputation

OBJECTIVE

The objectives of the study were to compare the clinical efficacy and adverse effects of two analgesic protocols consisting of bupivacaine liposome injectable solution (BLIS) and 0.5% bupivacaine and fentanyl for postsurgical analgesia in dogs undergoing limb amputation.

STUDY DESIGN

Randomized, double-blind, prospective, controlled, intent-to-treat, clinical noninferiority trial.

ANIMALS

Forty client-owned dogs.

METHODS

Dogs undergoing amputation were randomly assigned to either the BLIS or control group. Postoperative pain, sedation, nausea, and amount eaten were assessed using appropriate scales at 6, 12, 18, and 24 h by trained individuals blinded to the treatment protocol. Rescue analgesia was provided for Glasgow composite measure pain scale (short form) (CMPS-SF) scores of 5 or above. Clients were requested to pain score their dogs at home using a visual analogue scale (VAS) for 48 h following discharge.

RESULTS

Forty dogs completed this study (20 control dogs and 20 BLIS dogs). The BLIS and control groups were equivalent for sedation, nausea, amount eaten, and pain, at all time periods except at 6 h (p < .01), when the BLIS group pain score was lower.

CONCLUSION

The BLIS provided equivalent analgesia with fewer adverse effects than fentanyl constant rate infusion (CRI) following limb amputation. Rescue analgesia was provided to five dogs in the BLIS group and four in the control group, and there was no statistical difference. Nausea scores did not differ statistically.

CLINICAL SIGNIFICANCE

As BLIS provides equivalent analgesia, this may allow for decreased reliance on opioids in the immediate postoperative period.

A validation study to analyze the reliability of center of pressure data in static posturography in dogs

Introduction

Center of pressure (COP) parameters are frequently assessed to analyze movement disorders in humans and animals. Methodological discrepancies are a major concern when evaluating conflicting study results. This study aimed to assess the inter-observer reliability and test-retest reliability of body COP parameters including mediolateral and craniocaudal sway, total length, average speed and support surface in healthy dogs during quiet standing on a pressure plate. Additionally, it sought to determine the minimum number of trials and the shortest duration necessary for accurate COP assessment.

Materials and methods

Twelve clinically healthy dogs underwent three repeated trials, which were analyzed by three independent observers to evaluate inter-observer reliability. Test-retest reliability was assessed across the three trials per dog, each lasting 20 seconds (s). Selected 20 s measurements were analyzed in six different ways: 1 × 20 s, 1 × 15 s, 2 × 10 s, 4 × 5 s, 10 × 2 s, and 20 × 1 s.

Results

Results demonstrated excellent inter-observer reliability (ICC ≥ 0.93) for all COP parameters. However, only 5 s, 10 s, and 15 s measurements achieved the reliability threshold (ICC ≥ 0.60) for all evaluated parameters.

Discussion

The shortest repeatable durations were obtained from either two 5 s measurements or a single 10 s measurement. Most importantly, statistically significant differences were observed between the different measurement durations, which underlines the need to standardize measurement times in COP analysis. The results of this study aid scientists in implementing standardized methods, thereby easing comparisons across studies and enhancing the reliability and validity of research findings in veterinary medicine.

Pelvic limb anesthesia and analgesia in dogs undergoing tibial plateau leveling osteotomy (TPLO): A survey of board-certified anesthesiologists

OBJECTIVE

To report the locoregional anesthesia and analgesia preferences of veterinary anesthesiologists for use in dogs undergoing a TPLO and determine any association with specialty college, time from board-certification, or employment sector.

STUDY DESIGN

Cross sectional study.

SAMPLE POPULATION

Diplomates of the American (ACVAA) and European (ECVAA) Colleges of Veterinary Anesthesia and Analgesia.

METHODS

An electronic survey was distributed to diplomates and responses were used to determine associations between preferred methods.

RESULTS

The survey response rate was 28% (141/500) with 69% (97/141) of ACVAA diplomates and 31% of diplomates with ECVAA (44/141) certification. Peripheral nerve block (PNB) was preferred by 79% (111/141) of all diplomates, lumbosacral epidural (LE) by 21% (29/141), and peri-incisional infiltration (PI) by <1% (1/141). There was no association (p = .283) with specialty college. There was an association (p < .001) with time from board-certification with increased preference for LE when >10-years from certification and PI preferred by only those board-certified >20-years ago. There was an association with employment sector (p = .003) with more academic diplomates preferring LE. Anesthesiologists reported that treatment decisions were affected by various factors including time pressure and surgeon influence.

CONCLUSION

Diplomates of ACVAA and ECVAA prefer PNB as the locoregional method of pelvic limb anesthesia in dogs undergoing TPLO. A greater percentage of newer and private practice diplomates prefer PNB while a larger percentage of senior and academic diplomates prefer LE. Decision making is multifactorial and includes perceived time pressure and surgeon influence.

CLINICAL SIGNIFICANCE

Veterinary anesthesiologists prefer and frequently use PNB in dogs undergoing TPLO and surgeon influence may affect their chosen treatment.

Kinetic symmetry indices and standing gait analysis: A review of current methods and data

Kinetic gait data is used to evaluate a dog's orthopedic soundness and to assess treatment response in clinical trials. It captures ground reaction forces (GRFs) generated by the interactions between an animal's limb and the ground and can be collected using force plates and pressure sensitive walkways. Historically, gait data were most commonly analyzed from a single, most clinically affected, limb produced while the dog walks or trots. More recently, symmetry indices, calculated using multiple methods, have been used to evaluate forces between paired limbs, as a method of evaluating multi-joint disease. However, when dogs are non-weight bearing lame (NWB) or have extreme mobility impairment, walking or trotting data can be difficult or impossible to collect. For these instances, standing gait analysis has been suggested as an option to collect non-zero data points. This review focuses on the reported methods of data collection for standing gait data, as well as methods of symmetry index calculation, and their use reported in the veterinary literature.

2022 AAHA Pain Management Guidelines for Dogs and Cats

These updated guidelines present a practical and logical approach to the assessment and management of acute and chronic pain in canine and feline patients. Recognizing pain is fundamental to successful treatment, and diagnostic guides and algorithms are included for assessment of both acute and chronic pain. Particularly for chronic pain, capturing owner evaluation is important, and pain-assessment instruments for pet owners are described. Expert consensus emphasizes proactive, preemptive pain management rather than a reactive, "damage control" approach. The guidelines discuss treatment options centered on preemptive, multimodal analgesic therapies. There is an extensive variety of pharmacologic and nonpharmacologic therapeutic options for the management of acute and chronic pain in cats and dogs. The guidelines include a tiered decision tree that prioritizes the use of the most efficacious therapeutic modalities for the treatment of acute and chronic pain.

Best practices for measuring and reporting ground reaction forces in dogs

Kinetic gait analysis and ground reaction forces (GRFs) have been used in hundreds of scientific manuscripts. Specific methodology, interpretation of results, and translation to clinical veterinary medicine have been inconsistent. This impedes the advance of veterinary medicine and poses a risk to patients. The objective of this report was to address methodological variations and share our consensus on a recommended approach with viable alternatives to data collection methods, analysis, reporting, and interpretation for GRFs in the dog. Investigators with experience performing kinetic gait analysis reviewed the literature and discussed the topics that most influenced GRF data collection, reporting, and interpretation. Methodological variations were reported and a consensus from the group was devised. There are several reasonable alternatives to collect, report, and interpret GRFs in dogs appropriately. Attention to detail is required in several areas to collect and report them. This review and consensus report should assist future investigations and interpretations of studies, optimize comparison between publications, minimize use of animals, and limit the investment in cost and time.

Comparison of the analgesic effects of morphine and tramadol after tumor surgery in dogs

BACKGROUND

Pain thresholds may differ between animal species. It may even vary among individuals of the same species. Therefore, assessing pain in animals is challenging.

AIMS

The objective of the present study was to compare the analgesic effects of tramadol with morphine.

METHODS

The study was carried out on randomly selected 20 dogs with tumors in different breeds and gender. After induction of anesthesia with propofol, dogs were intubated, and anesthesia was maintained with sevoflurane. Intravenous fentanyl citrate was used for intraoperative analgesia after stabilization of the anesthesia. When the tumors were surgically removed and the operation was completed, dogs were divided into two groups to give the postoperative analgesic agent. The first 10 dogs to be investigated were identified as the morphine group and the second 10 dogs as the tramadol group. Postoperative pain scores, heart rates, respiratory rates, and body temperatures were recorded at 0, 4, 8, 12, 16, 20, and 24 hours after the operation.

RESULTS

Pain scores were lower in the morphine group than in the tramadol group during all postoperative processes.

CONCLUSION

As a result, it was determined that tramadol has immediate analgesic effects than morphine; however, morphine provides better analgesia than tramadol.

Evaluation of prescribing practices for gabapentin as an analgesic among veterinary professionals

OBJECTIVE

To describe the prescribing practices for gabapentin as an analgesic within the veterinary community.

STUDY DESIGN

Anonymous online voluntary survey.

POPULATION

A total of 718 veterinarians within the United States and Canada, including general practitioners and diplomates of the American Colleges of Veterinary Anesthesia and Analgesia, Emergency and Critical Care, Surgery and Internal Medicine.

METHODS

An anonymous online survey was used to gather information about individual prescribing practices for gabapentin including frequency of use, reasons for prescribing and procedures for authorizing refill requests. Questions specific to gabapentin covered mechanisms of action, perceptions of efficacy and the potential for abuse in people. Dunn's test for multiple comparisons and pairwise Mann-Whitney U test were used to evaluate relationships between veterinary specialty and survey responses.

RESULTS

A total of 718 veterinarians responded to the survey, 528 (73.5%) answered all questions of the survey to completion. Frequency of prescribing was high with 365/529 (69.0%) of respondents prescribing gabapentin as an analgesic on a daily or weekly basis. Surgeons and general practitioners used gabapentin significantly more frequently than other groups, with surgeons more likely to prescribe gabapentin for postoperative pain. The most common reason [254/517 (49.1%)] survey respondents prescribed gabapentin as an analgesic was because administration of a non-steroidal anti-inflammatory medication was contraindicated for that animal. The majority of survey respondents [362/527 (68.7%)] considered the abuse potential of gabapentin to be low in people.

CONCLUSIONS AND CLINICAL RELEVANCE

Veterinary prescribing practices for gabapentin closely mirrored that of human physicians, with gabapentin being prescribed frequently and for uses largely unrelated to its labeled indication. The perception of the potential for abuse of gabapentin is low within the veterinary community.

Post-operative analgesia following TPLO surgery: A comparison between cimicoxib and tramadol

OBJECTIVE

To compare the analgesic effects of oral administration of cimicoxib and tramadol over a 30 day period following Tibial Plateau Leveling Osteotomy and partial menisectomy in dogs.

DESIGN

Randomized, double blinded, prospective clinical trial.

ANIMALS

42 adult client-owned dogs with unilateral cranial cruciate ligament disease and partial meniscal tears.

METHODS

Dogs were allocated into 2 treatment groups (cimicoxib or tramadol). Weight bearing while standing, thigh circumference, flexion and extension range of motions, wound classification, adverse effects, Visual Analogue Scale (VAS), Glasgow Composite Measure Pain Scale (CMPS-SF) and Helsinki Chronic Pain Index (HCPI) questionnaire and limb function by means of pressure platform gait analysis were recorded before surgery and at several time points after surgery for 30 days. Outcome measures were compared at each time point among groups.

RESULTS

A significant improvement in two objective measures of gait of the cimicoxib group: the vertical impulse on day 1 and day 20 and the peak vertical force on day 20 were significantly improved when compared to the tramadol group. However, no difference was seen for the VI or PVF of dogs on the other days compared. In addiction there was no difference in the weight bearing while standing, thigh circumference, wound classification, adverse effects, VAS, CMPS-SF and HCPI. We did not observe a difference in the number of adverse effects measured in this study with the exception of hock edaema.

CONCLUSIONS AND CLINICAL RELEVANCE

A significant difference was not found in long-term postoperative analgesia provided by cimicoxib or tramadol in dogs undergoing TPLO when subjective parameters (with the exception of knee joint range of motion) were evaluated, but use of the force plate analysis revealed a significant difference between groups at T20 for both PVF and VI. The use of cimicoxib improved the limb function and ROM and reduced the occurrence of hock edema, in the first 20 days after surgery, without any additional side effects, compared to tramadol. Thus, the use of cimicoxib should be preferred to tramadol alone in clinical cases similar to the ones included in this study.

Evidence for anti-inflammatory effects of firocoxib administered to mares with experimentally induced placentitis

PROBLEM

Minimal evidence exists supporting therapeutic selections for equine placentitis. The goal of this study was to characterize the anti-inflammatory effects of firocoxib when administered to mares with placentitis.

METHODS

Mares (gestation D270-300) were assigned to: INFECT (n = 6; placentitis, no treatment), FIRO (n = 6; placentitis, firocoxib, 0.1 mg/kg, PO, daily), and NORM (n = 6; no infection/treatment). Allantoic fluid (8 hours, 24 hours, birth) and amniotic fluid (birth) were collected from mares after infection. Concentrations of IL-1β, IL-6, TNF-α, IL-10, PGF_2α , and PGE₂ in fluids were measured by ELISA. mRNA expression of IL-1β, IL-6, TNF-α, IL-8, IL-10, matrix metalloproteinases (MMPs) -1, 3, and 9 in fetal membranes/fetuses was quantified using real-time PCR.

RESULTS

Allantoic TNF-α concentrations were lowest in FIRO at 8 hours and 24 hours post-infection; IL-6 concentrations were lower in FIRO than NORM at 8 hours, lower in FIRO than INFECT at 24 hours post-inoculation, and lower in NORM than FIRO or INFECT at birth. Marginal mean allantoic IL-β and IL-10 concentrations were lower in FIRO and NORM than INFECT. Amniotic fluid cytokines were lowest in NORM with all measurements in that group being below the limit of detection. Allantoic PGF_2α concentrations were lower in FIRO and INFECT than NORM at 8 hours post-inoculation, and lower in FIRO than INFECT or NORM at 24 hours post-inoculation. Allantoic PGE₂ concentrations were lower in FIRO than INFECT. Amniotic PGF_2α and PGE₂ concentrations were lower in NORM than INFECT. In fetal membranes, group differences with respect to IL-1β, IL-6, IL-8, and MMP1 were dependent on tissue type.

CONCLUSIONS

Data suggest a suppressive effect of firocoxib administration on cytokine and prostaglandin production in mares with placentitis.

Is ECLIA Serum Cortisol Concentration Measurement, an Accurate Indicator of Pain Severity in Dogs with Locomotor Pain?

Simple Summary

Serum cortisol level reflects the activity of stress axis, ethological alterations, acute and chronic pain, life quality, or psychogenic stress. Although it is stated that stress can produce a measurable influence on the cortisol level, a certified value of this pain biomarker in dogs was not generally accepted yet. This interdisciplinary research emerged from the need for information in this field since not many studies were focused mainly on comparative analysis. We consider this field as a hot topic with various possible applications. Our survey is a methodological study within the fields of behavior and veterinary sciences, being relevant for the dog’s pain assessment. Results are having the guarantee of the high standard analysis of serum specimens, and using the updated Cortisol assay, with serum cortisol determined by Electrochemiluminescence immunoassay. We consider that our work could refresh the information in this field. Yet, an area of interest, specific pathology and pain particularities in a dog, being studied more and more in the last decade. What we can say is that serum cortisol limits cannot be adopted as a single and accurate pain marker in dog species, our study confirming these values, as non-conclusive for the assessment of the real pain levels in the dogs.

Abstract

The purpose of determining serum cortisol level is to reflect the activity of stress axis, ethological alterations, acute and chronic pain, life quality, or psychogenic stress. Although it is stated that stress can produce a measurable influence on the cortisol level, a certified value of this pain biomarker in dogs was not generally accepted yet. This study aimed to investigate if serum cortisol measured follows allopathic treatments only, or it is associated with physiotherapy, point out pain level in dogs with orthopedic disease, which could reveal the healing progress. The diagnostic identified: hip dysplasia, cranial cruciate ligament rupture, or intervertebral disc disease. Ortolani and Barden tests, together with clinical examination, drawer sign, and tibia compression test, were done in dogs exhibiting postures, and motion alteration, and X-Ray confirmed. A total of 30 dogs were grouped in healthy (n = 10) and pain groups (n = 20), the blood sampling is done at the beginning of the investigation, and after ten days of the study. Dogs were handled in two ways: G1—treated with Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) only and respectively, G2—by therapy and physiotherapy. The analysis was performed on a Roche Cobas Analyzer (Roche, USA), serum cortisol being determined by Electrochemiluminescence immunoassay (ECLIA), and statistics using ANOVA, following Tukey’s Multiple Comparison Test. The results revealed that, out of ten specimens in the Control group, nine were within the normal limits: 5–65 ng × mL⁻¹ (24.76 ± 19.48678), and one sample under the set limit. In G1, it was observed that the plasmatic P1 values were below the levels of P2, in six situations. In G2, although the status of all subjects improved radically with the removal or evident reduction of pain, confirmed clinically and imagistically, the P2 values in five dogs were higher than the initial P1 values, and in contradiction with the observed clinical reality. Comparing results, the mean difference in G1 was 0.41, and in G2 = 2.54, with an SD for G1 = 13.38, and G2 = 16.66, registering moderate development. Standard deviation illustrated that the values of treated groups were highly spread throughout the interval, and the serum cortisol assay did not generate significant statistical differences between groups in our case. This inferred the doubt whether the used detection method or values registered correctly indicates the pain levels in dog species.

Comparison of liposomal bupivacaine and 0.5% bupivacaine hydrochloride for control of postoperative pain in dogs undergoing tibial plateau leveling osteotomy

OBJECTIVE

To compare liposome-encapsulated bupivacaine (LEB) and (nonliposomal) 0.5% bupivacaine hydrochloride (0.5BH) for control of postoperative pain in dogs undergoing tibial plateau leveling osteotomy (TPLO).

ANIMALS

33 client-owned dogs.

PROCEDURES

In a randomized clinical trial, dogs undergoing TPLO received LEB (5.3 mg/kg [2.4 mg/lb]) or 0.5BH (1.5 mg/kg [0.68 mg/lb]) by periarticular soft tissue injection. All dogs received carprofen (2.2 mg/kg [1 mg/lb], SC, q 12 h) beginning at extubation. Signs of pain were assessed at extubation and predetermined times up to 48 hours later with the Colorado State University-Canine Acute Pain Scale and Glasgow Composite Pain Scale-Short Form. A pressure nociceptive threshold device was used at the affected stifle joint before surgery and at 5 postoperative time points. Methadone (0.1 mg/kg [0.05 mg/lb], IV) was administered if the Colorado State University pain scale score was ≥ 2 (scale, 0 to 4). Surgical variables; pain scores; pressure nociceptive thresholds; times to first administration of rescue analgesic, first walk, and first meal consumption; and total opioid administration were compared between treatment groups.

RESULTS

28 dogs completed the study. Dogs administered LEB were less likely to require rescue analgesia and received lower amounts of opioids than dogs administered 0.5BH. There were no significant intergroup differences in other measured variables.

CONCLUSIONS AND CLINICAL RELEVANCE

The LEB appeared to provide adequate analgesia after TPLO with lower requirements for opioid treatments, which may allow dogs to be discharged from the hospital earlier than with traditional pain management strategies.

Pharmacokinetics and analgesic efficacy of intranasal administration of tramadol in dogs after ovariohysterectomy

OBJECTIVE

To assess analgesic efficacy and the pharmacokinetics of intranasal (IN) tramadol in dogs following ovariohysterectomy.

STUDY DESIGN

Randomized, blinded clinical study.

ANIMALS

A total of 30 bitches undergoing elective ovariohysterectomy.

METHODS

Dogs were randomly assigned to one of three experimental groups (10 dogs per group): IN tramadol 4 mg kg^-1 (group T-IN), intravenous (IV) tramadol 4 mg kg^-1 (group T-IV) and IV methadone 0.2 mg kg^-1 (group M). Drugs were administered at extubation. At established time points (before surgery and up to 8 hours after drug administration) analgesia was assessed using the Italian version of the Glasgow Composite Measure Pain Scale Short Form and physiological variables were recorded. To determine the pharmacokinetics of IN tramadol, blood samples were collected at predetermined time points. Shapiro-Wilk test was used to assess whether data were normally distributed and consequently parametric or non parametric tests were applied. A p value < 0.05 was considered significant.

RESULTS

No significant intergroup differences were observed in the dogs that were administered rescue analgesia and time of its administration. Excluding dogs that were administered rescue analgesia, no significant intergroup differences emerged in pain scores and physiological variables, except for a lower rectal temperature in group M compared with the tramadol groups. After IN administration, tramadol was rapidly absorbed into the systemic circulation, reaching its maximum concentration (range 74.74-200.29 ng mL^-1) within 30-60 minutes, it then decreased rapidly and was detectable in plasma for up to 2 hours after treatment in all dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

IN tramadol administration appears to be as effective as IV tramadol and methadone treatments in pain management of dogs after elective ovariohysterectomy. Given its low concentrations and short detection time in plasma after the IN route, systemic tramadol action appears unlikely.

Adjuvant Analgesics in Acute Pain Management

Adjuvant analgesics (ie, gabapentin, tramadol, and ketamine) are commonly used in small animal practice. Most of these drugs are prescribed for outpatients, when pain is refractory to classic analgesics (ie, local anesthetics, opioids, and nonsteroidal antiinflammatory drugs [NSAIDs]), or when contraindications exist to the administration of other analgesics, including NSAIDs. This article reviews the mechanisms of action, clinical use, potential adverse effects, and current evidence of adjuvant analgesics in the treatment of acute pain in companion animals. These drugs should be considered as alternatives aimed at reducing or replacing opioids.

Assessment of the efficacy of firocoxib (Previcox®) and grapiprant (Galliprant®) in an induced model of acute arthritis in dogs

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) are an important tool in the management of canine osteoarthritis, with the most recent introduction into the category being grapiprant, a piprant that selectively targets the EP4 prostaglandin receptor. To date there have been no efficacy studies comparing grapiprant with other NSAIDs. A randomized, two-sequence, assessor-blinded study involving two separate experiments was undertaken to measure the potency and persistence of acute pain control over 24 h resulting from a single oral dose of either firocoxib (Previcox®) or grapiprant (Galliprant®) in an acute arthritis model.

Results

Force-plate derived lameness ratios (0, no force recorded on the plate; 1, normal force) for the untreated group remained at 0 for most post-arthritis induction (PAI) assessments in both experiments. Throughout Experiment 1, mean PAI lameness ratios of the firocoxib-treated group remained at or above 0.80. In the grapiprant-treated group, ratios were 0 at 5 and 7 h PAI (7 and 9 h post-treatment), and 0.16 at 10 h PAI (12 h post-treatment). For lameness ratios, relative to the firocoxib group, the control and grapiprant group ratios were significantly lower at each PAI assessment (p ≤ 0.026 and p < 0.001, respectively), except at 1.5 h PAI at which acute pain was still not installed in untreated control dogs. In Experiment 2 the mean lameness ratios for the control group were 0 at 3, 5 and 7 h PAI, and in the grapiprant group at 5, 7 and 10 h PAI (i.e., 19, 21, and 24 h post-treatment). In the firocoxib group the lowest mean lameness ratio of 0.36 occurred at 3 h PAI (i.e. 17 h post-treatment). Except at 1.5 and 3 h PAI (i.e. 15.5 and 17 h post-treatment), due to the needed time for pain to install in the untreated control dogs, the lameness ratio differences between the firocoxib and both the control and grapiprant groups were significant at all assessments (p ≤ 0.033 for both groups). No significant differences were detected between the grapiprant and control groups in either experiment.

Conclusions

Firocoxib treatment prior to induction of arthritis in dogs resulted in a high level of analgesia from the first post-treatment assessment at 1.5 h through 24 h post-treatment. The reduction in lameness provided by firocoxib was consistently superior to that provided by grapiprant, which was not significantly different from untreated controls.

Oral Coadministration of Fluconazole with Tramadol Markedly Increases Plasma and Urine Concentrations of Tramadol and the O-Desmethyltramadol Metabolite in Healthy Dogs

Tramadol is used frequently in the management of mild to moderate pain conditions in dogs. This use is controversial because multiple reports in treated dogs demonstrate very low plasma concentrations of O-desmethyltramadol (M1), the active metabolite. The objective of this study was to identify a drug that could be coadministered with tramadol to increase plasma M1 concentrations, thereby enhancing analgesic efficacy. In vitro studies were initially conducted to identify a compound that inhibited tramadol metabolism to N-desmethyltramadol (M2) and M1 metabolism to N,O-didesmethyltramadol (M5) without reducing tramadol metabolism to M1. A randomized crossover drug-drug interaction study was then conducted by administering this inhibitor or placebo with tramadol to 12 dogs. Blood and urine samples were collected to measure tramadol, tramadol metabolites, and inhibitor concentrations. After screening 86 compounds, fluconazole was the only drug found to inhibit M2 and M5 formation potently without reducing M1 formation. Four hours after tramadol administration to fluconazole-treated dogs, there were marked statistically significant (P < 0.001; Wilcoxon signed-rank test) increases in plasma tramadol (31-fold higher) and M1 (39-fold higher) concentrations when compared with placebo-treated dogs. Conversely, plasma M2 and M5 concentrations were significantly lower (11-fold and 3-fold, respectively; P < 0.01) in fluconazole-treated dogs. Metabolite concentrations in urine followed a similar pattern. This is the first study to demonstrate a potentially beneficial drug-drug interaction in dogs through enhancing plasma tramadol and M1 concentrations. Future studies are needed to determine whether adding fluconazole can enhance the analgesic efficacy of tramadol in healthy dogs and clinical patients experiencing pain.

Agreement among anesthesiologists regarding postoperative pain assessment in dogs

OBJECTIVE

To establish evidence for the validity and reliability of three commonly used pain scales in dogs when assessed by video by specialists in anesthesia.

STUDY DESIGN

Mixed-method test-retest observational study.

SUBJECTS

A group of six American College of Veterinary Anesthesia and Analgesia board-certified specialists and 31 postoperative dogs.

METHODS

The evaluators scored 31 dogs using a visual analogue scale (VAS), numeric rating scale (NRS), and Glasgow pain scale (GPS). The evaluators individually scored the dogs using all three scales together and subsequently, at 3 month intervals, using each of the scales apart. Then, all evaluators in one room reviewed 23 of the videos. A camera was positioned for video and audio recording of discussion about the videos. Intra- and interobserver reliability was determined using a two-way random model intra-class correlation coefficient (ICC).

RESULTS

Linear regression indicated a strong correlation among all scales when assigned together (VAS versus NRS, p < 0.0001, R² = 0.93; VAS versus GPS, p < 0.0001, R² = 0.59; and NRS versus GPS, p < 0.0001, R² = 0.61) and apart (VAS versus NRS, p < 0.0001, R² = 0.68; VAS versus GPS, p < 0.0001, R² = 0.40; and NRS versus GPS, p < 0.0001, R² = 0.47). Posture, appearance, vocalization, stiffness, interaction between the animal and a person and response to palpation were identified as important variables for assessing pain. Intra-observer reliability produced average ICC values of 0.90 for VAS, 0.89 for NRS and 0.85 for GPS. Interobserver reliability produced average ICC values when scores were assigned together (VAS: 0.93, NRS: 0.93 and GPS: 0.93) and when done separately (VAS: 0.91, NRS: 0.93 and GPS: 0.95).

CONCLUSIONS AND CLINICAL RELEVANCE

The preferred use of the VAS and NRS over the use of the GPS should be cautiously considered for research applications when experts are observers. Revisions of the GPS to clarify descriptors and remove or modify items that may not be associated with pain in dogs should be considered.

Post-operative outcomes of surgical and chemical castration with zinc gluconate in dogs presenting to veterinary field clinics

The objective of this study was to characterize post-operative outcomes of chemical castration as compared to surgical castration performed by existing municipal field clinics. Fifty-four healthy adult male dogs underwent chemical castration with zinc gluconate solution and 55 healthy adult male dogs underwent surgical castration in veterinary field clinics. Dogs in each group were evaluated for swelling, inflammation, and ulceration (chemical castration) or dehiscence (surgical castration) at Days 3, 7, and 14 following castration. More surgically castrated dogs required medical intervention than chemically castrated dogs (P=0.0328); the number of dogs requiring surgical repair within each group did not differ (P=0.3421). Seven chemically castrated dogs and 22 surgically castrated dogs experienced swelling, inflammation, and/or ulceration; all were managed medically. Two chemically castrated dogs experienced scrotal ulceration requiring surgical castration at Days 3 and 7. One surgically castrated dog experienced partial incisional dehiscence requiring surgical repair at Day 3. Our results suggest that chemical castration of dogs in field clinics is a feasible alternative to surgical castration, but proper follow-up care should be ensured for at least 7days post-procedurally.

The Association of Shelter Veterinarians' 2016 Veterinary Medical Care Guidelines for Spay-Neuter Programs

As community efforts to reduce the overpopulation and euthanasia of unwanted and unowned cats and dogs have increased, many veterinarians have increasingly focused their clinical efforts on the provision of spay-neuter services. Because of the wide range of geographic and demographic needs, a wide variety of spay-neuter programs have been developed to increase delivery of services to targeted populations of animals, including stationary and mobile clinics, MASH-style operations, shelter services, community cat programs, and services provided through private practitioners. In an effort to promote consistent, high-quality care across the broad range of these programs, the Association of Shelter Veterinarians convened a task force of veterinarians to develop veterinary medical care guidelines for spay-neuter programs. These guidelines consist of recommendations for general patient care and clinical procedures, preoperative care, anesthetic management, surgical procedures, postoperative care, and operations management. They were based on current principles of anesthesiology, critical care medicine, infection control, and surgical practice, as determined from published evidence and expert opinion. They represent acceptable practices that are attainable in spay-neuter programs regardless of location, facility, or type of program. The Association of Shelter Veterinarians envisions that these guidelines will be used by the profession to maintain consistent veterinary medical care in all settings where spay-neuter services are provided and to promote these services as a means of reducing sheltering and euthanasia of cats and dogs.

Tramadol metabolism to O-desmethyl tramadol (M1) and N-desmethyl tramadol (M2) by dog liver microsomes: Species comparison and identification of responsible canine cytochrome P-450s (CYPs)

Tramadol is widely used to manage mild to moderately painful conditions in dogs. However, this use is controversial since clinical efficacy studies in dogs showed conflicting results, while pharmacokinetic studies demonstrated relatively low circulating concentrations of O-desmethyltramadol (M1). Analgesia has been attributed to the opioid effects of M1, while tramadol and the other major metabolite (N-desmethyltramadol, M2) are considered inactive at opioid receptors. The aims of this study were to determine whether cytochrome P450 (CYP) dependent M1 formation by dog liver microsomes is slower compared with cat and human liver microsomes; and identify the CYPs responsible for M1 and M2 formation in canine liver. Since tramadol is used as a racemic mixture of (+)- and (-)-stereoisomers, both (+)-tramadol and (-)- tramadol were evaluated as substrates. M1 formation from tramadol by liver microsomes from dogs was slower than from cats (3.9-fold), but faster than humans (7-fold). However, M2 formation by liver microsomes from dogs was faster than from cats (4.8-fold) and humans (19-fold). Recombinant canine CYP activities indicated that M1 was formed by CYP2D15, while M2 was largely formed by CYP2B11 and CYP3A12. This was confirmed by dog liver microsomes studies that showed selective inhibition of M1 formation by quinidine and M2 formation by chloramphenicol and CYP2B11 antiserum, and induction of M2 formation by phenobarbital. Findings were similar for both (+)-tramadol and (-)-tramadol. In conclusion, low circulating M1 concentrations in dogs is explained in part by low M1 formation and high M2 formation, which are mediated by CYP2D15 and CYP2B11/CYP3A12, respectively.

Pilot, randomized, placebo-controlled clinical field study to evaluate the effectiveness of bupivacaine liposome injectable suspension for the provision of post-surgical analgesia in dogs undergoing stifle surgery

BACKGROUND

Local anesthetics are an important component of perioperative pain management, but the duration of action of available products is limited. We hypothesized that a single local infiltration of a novel bupivacaine liposome injectable suspension (AT-003) would provide clinically effective analgesia over a 72-h period. In a masked, randomized, placebo-controlled, multi-center pilot field study, dogs undergoing lateral retinacular suture placement for cranial cruciate insufficiency were randomly assigned to surgical site infiltration with AT-003 (5.3 mg/kg) or an equivalent volume of saline. Infiltration of the surgical site was done prior to closure. Primary outcome measure was the Glasgow Composite Measure Pain Scale (CMPS-SF) assessed prior to surgery and at 2, 4, 8, 12, 24, 30, 36, 48, 54, 60 and 72 h following surgery by trained individuals. Provision for rescue analgesia was employed. Repeated measures analysis of variance were utilized to test for possible differences between treatment groups and a success/failure analysis was also employed, based on the need for rescue analgesia.

RESULTS

Forty-six dogs were enrolled and evaluated. For CMPS-SF scores there was a significant overall treatment effect (p = 0.0027) in favor of AT-003. There were significantly more successes in the AT-003 group compared to placebo over each time period (p = 0.0001 for 0-24 h, p = 0.0349 for 0-48 h, and p = 0.0240 for 0-72 h). No significant adverse events were seen.

CONCLUSIONS

AT-003 (bupivacaine liposome injectable suspension) provided measurable local analgesia over a 72-h period following post-stifle surgery surgical site tissue infiltration. Further work is indicated to develop this product for clinical use.

Clinical efficacy of hydrocodone-acetaminophen and tramadol for control of postoperative pain in dogs following tibial plateau leveling osteotomy

OBJECTIVE

To evaluate clinical efficacy of hydrocodone-acetaminophen and tramadol for treatment of postoperative pain in dogs undergoing tibial plateau leveling osteotomy (TPLO). ANIMALS 50 client-owned dogs.

PROCEDURES

Standardized anesthetic and surgical protocols were followed. Each patient was randomly assigned to receive either tramadol hydrochloride (5 to 7 mg/kg, PO, q 8 h; tramadol group) or hydrocodone bitartrate-acetaminophen (0.5 to 0.6 mg of hydrocodone/kg, PO, q 8 h; hydrocodone group) for analgesia after surgery. The modified Glasgow composite measure pain scale was used to assess signs of postoperative pain at predetermined intervals by an investigator who was blinded to treatment group. Scoring commenced with the second dose of the assigned study analgesic. Pain scores and rates of treatment failure (ie, dogs requiring rescue analgesia according to a predetermined protocol) were compared statistically between groups.

RESULTS

12 of 42 (29%; 5/19 in the hydrocodone-acetaminophen group and 7/23 in the tramadol group) dogs required rescue analgesic treatment on the basis of pain scores. Median pain score for the hydrocodone group was significantly lower than that of the tramadol group 2 hours after the second dose of study analgesic. The 2 groups had similar pain scores at all other time points.

CONCLUSIONS AND CLINICAL RELEVANCE

Overall, differences in pain scores between dogs that received hydrocodone-acetaminophen or tramadol were minor. The percentage of dogs with treatment failure in both groups was considered unacceptable.

Comparison of carprofen and tramadol for postoperative analgesia in dogs undergoing enucleation

OBJECTIVE

To compare analgesia provided by carprofen and tramadol in dogs after enucleation.

DESIGN

Randomized, masked clinical trial.

ANIMALS

43 dogs.

PROCEDURES

Client-owned dogs admitted for routine enucleation were randomly assigned to receive either carprofen or tramadol orally 2 hours prior to surgery and 12 hours after the first dose. Dogs were scored for signs of pain at baseline (ie, before carprofen or tramadol administration) and at 0.25, 0.5, 1, 2, 4, 6, 8, 24, and 30 hours after extubation. Dogs received identical premedication and inhalation anesthesia regimens, including premedication with hydromorphone. If the total pain score was ≥ 9 (maximum possible score of 20), there was a score ≥ 3 in any of 5 behavioral categories (highest score possible per category was 3 or 4), or the visual analog scale (VAS) score was ≥ 35 (maximum possible score of 100) combined with a palpation score > 0, rescue analgesia (hydromorphone) was administered and treatment failure was recorded.

RESULTS

No differences were found in age, sex, or baseline pain scores between groups. Significantly more dogs receiving tramadol required rescue analgesia (6/21), compared with dogs receiving carprofen (1/22). Pain and VAS scores decreased linearly over time. No significant differences were found in pain or VAS scores between groups at any time point (dogs were excluded from analysis after rescue).

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study suggested that carprofen, with opioid premedication, may provide more effective postoperative analgesia than tramadol in dogs undergoing enucleation.

2015 AAHA/AAFP pain management guidelines for dogs and cats

RATIONALE

The robust advances in pain management for companion animals underlie the decision of the American Animal Hospital Association (AAHA) and American Association of Feline Practitioners (AAFP) to expand on the information provided in the 2007 AAHA/AAFP Pain Management Guidelines. The 2015 Guidelines summarize and offer a discriminating review of much of this new knowledge.

RELEVANCE

Pain management is central to veterinary practice, alleviating pain, improving patient outcomes, and enhancing both quality of life and the veterinarian-client-patient relationship. These Guidelines support veterinarians in incorporating pain management into practice, improving patient care.

APPROACHES

The management of pain requires a continuum of care that includes anticipation, early intervention, and evaluation of response on an individual patient basis. A team-oriented approach, including the owner, is essential for maximizing the recognition, prevention and treatment of pain in animals.

EVIDENCE BASE

The Guidelines include both pharmacologic and non-pharmacologic modalities to manage pain; they are evidence-based insofar as possible and otherwise represent a consensus of expert opinion. Behavioral changes are currently the principal indicator of pain and its course of improvement or progression, and the basis for recently validated pain scores. Post-surgical pain is eminently predictable but a strong body of evidence exists supporting strategies to mitigate adaptive as well as maladaptive forms. Chronic pain is dominated by degenerative joint disease (DJD), which is one of the most significant and under-diagnosed diseases of cats and dogs. DJD is ubiquitous, found in pets of all ages, and inevitably progresses over time; evidence-based strategies for management are established in dogs, and emerging in cats.

Adjunctive, pain-modifying, analgesic drugs

Outside the realm of nonsteroidal antiinflammatory drug(NSAID) and opioid exist a broad range of medications that exert an analgesic effect, or otherwise modify and protect against pain, by manipulating various targets along the nociceptive pathway. Strength of evidence for dogs and cats can vary widely, and this article will review the available literature that may guide clinical usage in these species.