Topic:Analgesia
Analgesia in horses involves the use of medications and techniques to alleviate pain caused by injury, surgery, or chronic conditions. Effective pain management is important for the welfare and recovery of equine patients, as unmanaged pain can lead to complications and prolonged healing. Common analgesic agents used in horses include non-steroidal anti-inflammatory drugs (NSAIDs), opioids, and local anesthetics. These agents work through various mechanisms to reduce pain perception and improve comfort. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacology, application, and clinical outcomes of analgesic strategies in equine medicine.
Effect of palmar digital perineural analgesia (as a model for “nerving”) on forelimb loading over varied surfaces at the walk and trot – a pilot study. Navicular syndrome is characterized by palmar foot pain and is a common cause of lameness in horses. Palmar digital neurectomy (nerving) removes sensation to the heel region of the hoof and may serve as a treatment for navicular-afflicted horses, while analgesia (blocking) results in temporary loss of sensation. Objective: The purpose of this pilot study was to examine the effect of loss of sensation in the heel on the forelimb area and force while tracking on soft and hard ground at the walk and trot. Methods: Three horses that scored a 0 or 1 on the AAEP lameness scale were fitted to Tekscan...
Pharmacopuncture with low-dose dexmedetomidine and saline aquapuncture at acupoint Governing Vessel 24 provides sedation in healthy adult horses. To evaluate sedation in horses following pharmacopuncture with dexmedetomidine at acupoint Governing Vessel 24 (GV-24) compared to aquapuncture at GV-24 or an equivalent dose of dexmedetomidine administered via IV or SC routes. Unassigned: 10 adult mares received 4 treatments in a blinded, randomized, crossover design: (1) dexmedetomidine administered at GV-24 (DexmedGV24; 1 μg/kg); (2) saline administered at GV-24 (SalineGV24; 1.5 mL); (3) dexmedetomidine administered SC on the lateral neck (DexmedSC; 1 μg/kg); or (4) dexmedetomidine administered IV (DexmedIV; 1 μg/kg). Sedation scores (fa...
Survey describing the perspectives and practices of Australian veterinarians to pain management in horses. To describe Australian practices and attitudes regarding equine analgesia. Methods: Cross-sectional anonymous, voluntary survey of Australian veterinarians treating equine patients. Methods: Australian veterinarians in equine or mixed practices completed a six-section, 60-question survey between November 2019 to August 2020. Information was gathered on demographics, analgesia prescription, pain assessment and attitudes surrounding specific analgesics. Respondents assigned a pain score ranging from 0 to 10 for various conditions; these were averaged to give each respondent an "average pain scor...
Effect of a Constant Rate Infusion of Ketamine on a Variable Rate Infusion of Xylazine in Standing Horses Undergoing Ventriculocordectomy and Laryngoplasty. Standing sedation in horses provides immobilization and analgesia for surgery while avoiding the high risks of general anesthesia. Ketamine at subanesthetic doses may enhance sedation and reduce xylazine requirements, but evidence in clinical settings is limited. In a randomized blinded trial, we evaluated whether adding a low-dose ketamine infusion could reduce the xylazine dose required for effective sedation during standing ventriculocordectomy and laryngoplasty. Fifty-one horses were randomly assigned to sedation with xylazine alone (SX group) or xylazine plus ketamine (KX group) in a cont...
An Ultrasound-Guided Thoracolumbar Erector Spinae Plane Block: An Experimental Preliminary Study in Horses. The objective of this study was to evaluate the feasibility and efficacy of the ultrasound-guided thoracolumbar erector spinae plane (TL-ESP) block in standing horses. A total of 24 injections ( = 12) were performed at the L1 level using either 0.1 mL/kg of saline solution (SS group) or 2% lidocaine (LID group). The block feasibility was assessed based on needle visualization and injection time, while efficacy was evaluated through craniocaudal and dorsoventral (DV) spread using the pinprick technique over 270 min. Desensitization was observed at least once in 100% of horses in the LID group a...
Pregabalin contributes to increased recovery time from isoflurane anaesthesia for magnetic resonance imaging in horses. Pregabalin reduces excitatory neurotransmitter release and is used for anxiolysis in humans, cats, and horses. The effects of pregabalin on equine recovery following isoflurane anaesthesia are unknown. Objective: To determine if pre-anaesthetic oral pregabalin influences recovery time and/or quality from isoflurane anaesthesia in horses undergoing elective magnetic resonance imaging (MRI) of the appendicular skeleton. Methods: Retrospective cohort study. Methods: Anaesthetic and recovery data from 52 healthy horses in which pregabalin (PG) was administered and 76 control horses (CG) undergoing...
Efficacy of caudal epidural injection of Xylazine-Lidocaine HCl and detomidine-lidocaine HCl in domestic horses (Equus ferus caballus). The current study was prepared to compare the efficacy of xylazine-lidocaine HCl and detomidine-lidocaine HCl following caudal epidural injection in horses, evaluating sedation, analgesia, physiological parameters, and hemato-biochemical values. This study was applied to six healthy adult horses (300-350 kg, > 4 years of age). The horses were randomly divided into two equal groups. Group 1 (seven horses) received xylazine (0.17 mg/kg bwt) + lidocaine HCl (0.06 mg/kg bwt), while Group 2 received detomidine (0.03 mg/kg bwt) + lidocaine HCl (0.06 mg/kg bwt) via caudal epidural inje...
Lameness improvement in horses with distal tarsal pain after intra-articular injection of botulinum neurotoxin type A. To evaluate the effect of IA injections of botulinum toxin type A (BoNT-A) in horses with chronic, naturally occurring distal tarsal osteoarthritis. Unassigned: 9 horses were selected after physical and radiographic assessments. Horses also underwent an objective lameness examination and were included if they had a hindlimb impact lameness (Pmin ≥ 3 mm), which positively responded (≥ 50%) to the tarsometatarsal and centrodistal joints' anesthetic block. Horses randomly received an intra-articular injection of BoNT-A or an equivalent volume of saline solution. Horses were reevaluated at pos...
Population pharmacokinetics and clinical evaluation of intravenous acetaminophen and its metabolites in Andalusian horses. To date, no intravenous pharmacokinetics (PK) studies have assessed acetaminophen or its major metabolites (acetaminophen-glucuronide and acetaminophen-sulphate) in horses. The influence of sex on acetaminophen metabolism in horses is unclear, and Monte Carlo simulations have not been applied to explore potential clinical applications. This study aimed to determine the intravenous PK and safety of acetaminophen in Andalusian horses at 10 and 20 mg/kg, evaluate sex as a covariate, and simulate clinical regimens. Twenty mares and twenty stallions received intravenous acetaminophen, and plasma ...
The effect of 0.5 mL mepivacaine administered as an abaxial sesamoid nerve block on lameness of horses with digital pain did not differ significantly from that of 2.5 mL of mepivacaine. To compare the effect of 2.5 mL 2% mepivacaine to the effect of 0.5 mL 2% mepivacaine administered over each palmar digital nerve, as an abaxial sesamoid nerve block (ASNB), to 6 horses lame because of naturally occurring digital pain. Unassigned: In a crossover study design with 3 horses in each group, the trotting gait of the horses was analyzed with an inertial sensor-based, motion-analysis system (Q with Lameness Locator; Equinosis LLC) immediately before and after treatment with either 0.5 or 2.5 mL mepivacaine administered over each nerve near the base of the proximal sesamoid bone of th...
Exploring the genetic influences on equine analgesic efficacy through genome-wide association analysis of ranked pain responses. Multimodal analgesic administration is a promising strategy for mitigating side effects typically associated with analgesia; nevertheless, variation in analgesic effectiveness still poses a considerable safety concern for both horses and veterinarians. Pharmacogenomic studies have started delving into genetic influences on varying drug effectiveness and related side effects. However, current findings have narrow implications and are limited in their ability to individualize analgesic dosages in horses. Hydromorphone and detomidine were administered to a cohort of 48 horses at standardized time...
Use of the rectus sheath block for perioperative analgesia in three foals undergoing omphalectomy and cystoplasty. Locoregional techniques promote multimodal analgesia and may reduce general anaesthetic requirements. However, there is limited evidence in foals. The rectus sheath block (RSB) is an interfascial plane block previously described in other species such as dogs, cats, pigs, and calves, and recently in foals, which targets desensitization of ventral abdominal midline. This block may provide an efficacious analgesic alternative for ventral celiotomies and umbilical surgeries. This case series reports the use of a bilateral RSB with 0.25-0.3 mL kg-1 bupivacaine (maximum dose of 2 mg kg-1) per hemiab...
Effects of vatinoxan on gastrointestinal motility, sedation, and antinociception during and after long-lasting detomidine infusion in horses. Sedation in horses is typically achieved using alpha-2 adrenoceptor agonists, although their use is associated with multiple side effects. A peripheral alpha-2 adrenoceptor antagonist, vatinoxan, can alleviate many of these. Objective: To evaluate the effects of vatinoxan infusion on gastrointestinal motility, sedation, and antinociception in horses sedated with detomidine infusion. Methods: Randomised, blinded cross-over in vivo experiments. Methods: Eight horses were given two 4-h infusions: detomidine (0.01 mg/kg + 0.015 mg/kg/h IV) (DET) and a combination of detomidine and vatinoxa...
Systemic, hemodynamic and neurological effects of caudal epidural administration of Neosaxitoxin in horses. The present study was conducted to evaluate the safety and the long-lasting anesthetic properties of Neosaxitoxin (NeoSTX) when injected into the intercoccygeal space in standing horses. A group of eighteen (n = 18) healthy client-owned mature crossbreed horses were enrolled in this study. Caudal epidural injection was ascertained by two methods, the "hanging drop" technique and radiographs. Horses were allocated into three groups (n = 6) each group receiving different dosages of NeoSTX. To assess the onset of action and duration of anesthesia, six horses received 20 μg in 2 mL, six 20...
Effects of constant intravenous infusion of detomidine alone or combined with butorphanol or methadone for standing sedation in horses: A randomized clinical trial. This study aimed to evaluate the sedation degree, cardiopulmonary effects, and detomidine-sparing during dental occlusal adjustment in standing horses using a bolus and constant rate infusion (CRI) of detomidine alone or in combination with butorphanol or methadone. In this randomized, blinded clinical trial, 24 healthy adult horses were assigned to the detomidine (DT), detomidine-butorphanol (DB), or detomidine-methadone (DM) group. DT received an intravenous bolus of detomidine (20 μg/kg), followed by CRI at 20 μg/kg/h. DB received detomidine (10 μg/kg) and butorphanol (0.02 mg/kg) boluse...
Evaluation of Spectral Entropy Monitor with Different Concentrations of Isoflurane in Horses. Spectral entropy and bispectral index (BIS) can differentiate between conscious and unconscious levels in horses. This study aimed to determine whether spectral entropy and BIS parameters can distinguish between different end-tidal isoflurane concentrations (EtIso, %), and whether these parameters change when a nociceptive stimulus is applied. Ten clinically healthy horses were anaesthetized using xylazine, diazepam, ketamine, and isoflurane. The following parameters were monitored: EtIso, response entropy (RE), state entropy (SE), RE-SE difference, BIS, and electromyography (EMG). Three EtIso...
Analgesic and Gastrointestinal Effects of Morphine in Equines. Morphine has significant clinical and analgesic effects in horses, but its impact on the gastrointestinal tract requires further understanding. This study assessed the analgesic and gastrointestinal effects of morphine in horses undergoing elective orchiectomy in the quadrupedal position. Thirty uncastrated male horses were randomly assigned to three groups: orchiectomy without morphine and sedation protocol (OSM), orchiectomy with morphine and sedation protocol (OM), and administration of morphine alone in the absence of orchiectomy (M). The anesthetic protocol involved acepromazine (0.05 mg/...
Facial expressions during compound interventions of nociception, conspecific isolation, and sedation in horses. Facial expressions in prey animals such as equines can convey information regarding their internal state and are therefore often used as cues for welfare and pain evaluation. The state of pain is commonly compared to a neutral state with little consideration given to other experiences that could affect the animal, although this situation is rare outside of experimental contexts. To evaluate the effect of managerial contexts on facial expressions from a nociceptive input, conspecific isolation and sedation with known physiological effects were compared to compound states of nociception. Using a...
Ultrasound-guided celiac plexus block increases intestinal motility in normal horses. To describe a technique for ultrasound-guided celiac plexus block in horses and characterize its effect on intestinal motility in healthy horses. Methods: This study was conducted from January 2022 through June 2022. In phase 1 (dye study), an ultrasound-guided technique was optimized, and dye deposition around the celiac plexus branches was evaluated via postmortem dissection in 6 horses. In phase 2 (experimental study), 6 healthy horses were fasted and sedated with 0.6 mg/kg xylazine, IV (experiment 1). After a washout period, the ultrasound-guided celiac plexus block with lidocaine 1% (1.3 ...
Effects of anesthetic protocol, procedure, and recovery stall and interval on the quality of recovery in repeatedly anesthetized horses. The objective of this prospective study was to investigate whether repeated consecutive general anesthesia in horses undergoing 2 different anesthetic protocols could lead to improved recovery scores. Six healthy female Standardbred horses (453 ± 57 kg; 6.5 ± 4.2 y old) underwent 4 anesthetic protocols over 12 to 13 wk. Procedures 1 and 4 were arthroscopic surgeries [induction: xylazine, diazepam, and ketamine; and maintenance: Fe'Isoflurane (1.1%), lidocaine (2 mg/kg body weight [BW], 50 to 100 μg/min per kg BW), dexmedetomidine (2.5 μg/h per kg BW)]. Procedures 2 and 3 were preparation f...
Doping Control Analysis of Methylsulfonylmethane in Horses. Methylsulfonylmethane (MSM), also known as dimethyl sulfone, is a naturally occurring sulphur-containing compound that can be found in plants, animals and humans. MSM can also be a metabolite of dimethyl sulfoxide (DMSO). Due to their anti-inflammatory and analgesic effects, both MSM and DMSO are prohibited substances in horseracing. As both substances are naturally occurring, their misuse in horses is controlled by International Residue Limits (IRL) of 1200 and 15 μg/mL, respectively, in horse urine as established by the International Federation of Horseracing Authorities. The elimination ...
Analgesic efficacy of tapentadol in chronic joint disorders in horses: plasma serotonin concentration and adrenocortical response as biomarkers of pain-induced stress. The study aimed to evaluate the analgesic efficacy of tapentadol in horses, by determining plasma serotonin concentration and adrenocortical response, as biomarkers of pain stress in chronic joint disorders. Thirty-six horses (20 females and 16 males) were divided into three groups of 12 subjects each: group A, osteoarthritis (OA), grade 3-4 lameness; group B, OA, grade 5 lameness; and group C, no OA, no lameness, were enrolled. The orthopedic examination included flexion tests, and radiological and ultrasound examinations. The degree of lameness has been estimated from 0 to 5 according to the...
Role of cannabidiolic acid or the combination of cannabigerol/cannabidiol in pain modulation and welfare improvement in horses with chronic osteoarthritis. Cannabidiol (CBD) is a non-psychotropic cannabinoid obtained from hemp (Cannabis sativa L.) used for pain management in companion animals including horses. The present study aimed to evaluate the efficacy of cannabidiolic acid (CBDA) and cannabigerol/cannabidiol oil (CBG/CBD) oral administration in alleviating pain in adult horses affected by chronic osteoarthritis (OA). Twenty-four horses (10 geldings and 14 mares), aged between 11 and 18 years old, were equally divided into two groups. One group received CBDA 15% oil and the other group received CBG/CBD oil (CBG20%-CBD10%) for 14 consecuti...
Impact of equine interactions on human acute pain perception: Two cross sectional studies. Research has demonstrated the effectiveness of Animal-Assisted Therapy, usually involving dogs, as a way to reduce pain in inpatient and outpatient populations. Here two studies investigate the effectiveness of interacting with horses for reducing human acute pain perception. Unassigned: In Study 1, a blood-pressure cuff was used to administer acute ischaemic pain to 70 adult participants, who were allocated to one of three groups: Equine Assisted Psychotherapy (EAP), Horse Interaction without EAP (HI), and a Control (no horses present). All participants engaged in an activity (finding a horse...
The effect of intramuscular atipamezole on head height and sedation scores in detomidine-sedated horses. To assess the effect of two different doses of intramuscular atipamezole on head height (HH) in horses after sedation with detomidine. Methods: Randomized, blinded, triple crossover study. Methods: Eight healthy adult horses. Methods: Baseline HH was measured before detomidine (40 μg kg) was injected intravenously. HH was measured at 10 and 20 minutes after injection. Then, saline, atipamezole 60 μg kg (AT60) or 120 μg kg (AT120) was injected intramuscularly. HH measurements were repeated at 10 minutes intervals for 100 minutes. HH data were analyzed with a linear mixed model. Significance ...
Evaluation of the Rostral Inferior Alveolar Nerve Block via the Mental Foramen in Equids: In Vivo Efficacy Testing. The use of proper sedative and regional anesthetic protocols is essential when performing equine dental surgical procedures under standing sedation. The efficacy of the rostral inferior alveolar nerve block via the mental foramen has not been previously studied. Aims of this study included determining the efficacy of the block, investigating whether any region (labial mucosa, alveolar mucosa, or teeth) was more reliably anesthetized, and if differences in efficacy existed between bilateral and unilateral blocks. In this blinded trial, 10 horses each were randomly assigned to receive a left uni...
Lidocaine’s Ineffectiveness in Mitigating Lipopolysaccharide-Induced Pain and Peristaltic Effects in Horses. The present study involved seven horses in a randomized crossover clinical trial to evaluate the effect of lidocaine on horses with induced endotoxemia. Horses received intravenous lidocaine (1.5 mg/kg bolus, followed by 0.05 mg/kg bwt/min) or placebo (0.9% sodium chloride at the same manner) one hour before LPS administration (0.03 μg/kg, IV infusion over 30 min). We monitored clinic and hematologic parameters, abdominal auscultation, ultrasound, and pain over time. No relevant clinical differences existed between treatments regarding peristalsis, abdominal pain, or any other parameters befo...
Sub-Tenon’s anesthesia in equine cataract surgery and vitrectomy: a retrospective case series (2018-2022). A retrospective data analysis was performed on 17 eyes from 13 horses which underwent a sub-Tenon's injection to facilitate phacoemulsification or pars plana vitrectomy under general anesthesia between 2018 and 2022. All procedures were performed by the same veterinary ophthalmologist. Seven eyes received a sub-Tenon's dose of 7 ml lidocaine (XylocainÒ, 2 % lidocaine hydrochloride, Germany, Aspen Germany GmbH), and 10 eyes received 7 ml mepivacaine (MepinaestÒ purum 2 %, mepivacaine hydrochloride, Switzerland, Gebro Pharma GmbH). Statistical analysis compared onset and duration of gl...
Retrospective evaluation of the impact of atropine administration on incidence of post-operative colic in healthy, isoflurane-anaesthetised horses. In anaesthetised horses, bradycardia secondary to high vagal tone can reduce cardiac output and blood pressure. The use of anticholinergics in horses is limited due to concerns about ileus and abdominal discomfort. This retrospective study sought to determine the prevalence of post-operative abdominal discomfort in healthy horses that received atropine under isoflurane anaesthesia. Methods: A retrospective evaluation of 222 general anaesthesia events between January 2019 and December 2019 was undertaken. Methods: One hundred and eleven horses that received atropine were identified, and 111 cas...