Morphine is an opioid analgesic used in veterinary medicine to manage pain in horses. It acts on the central nervous system by binding to specific receptors to alleviate discomfort associated with surgical procedures, injury, or chronic conditions. The administration of morphine in equine patients requires careful consideration of dosage and potential side effects, such as respiratory depression or gastrointestinal disturbances. Research on morphine use in horses explores its pharmacokinetics, efficacy, and safety profile. This page aggregates peer-reviewed studies and scholarly articles that investigate the application, effects, and implications of morphine administration in equine veterinary practice.
Vullo C, Gugliandolo E, Biondi V, Biffarella M, Catone G, Tambella AM.The aim of this study was to determine the most appropriate sedation protocol for a standing magnetic resonance imaging (MRI) examination in horses, comparing continuous rate infusions (CRIs) of detomidine and romifidine combined with a single bolus of morphine. Sixteen horses referred for standing low-field open-magnet MRI were randomly assigned to one of two sedation protocols. The horses were premedicated with 0.03 mg/kg of intramuscular acepromazine, and those animals belonging to Group D received an intravenous (IV) loading dose of detomidine (0.01 mg/kg) 30 min later, while those of Grou...
Haralambus R, Juri M, Mokry A, Jenner F.Effective management of postoperative pain is essential to ensure patient welfare, reduce morbidity and optimize recovery. Opioids are effective in managing moderate to severe pain in horses but concerns over their adverse effects on gastrointestinal (GI) motility and associated increased colic risk limit their widespread use. Studies investigating the impact of systemic opioids on both GI motility and colic incidence in horses have yielded inconclusive outcomes. Therefore, this retrospective study aims to assess the influence of systemic administration of butorphanol, morphine, and methadone ...
Floriano D, Gorenberg E, Watkins A, Hopster K.To test the influence of increasing injectate volumes on the regional effects of xylazine and morphine epidural analgesia, with the hypothesis that increasing volume produces more cranial spread of analgesia as determined by thermal threshold (TT) testing. Methods: 6 university-owned research/teaching horses (2 mares, 4 geldings) deemed healthy on physical examination and basic lameness evaluation, aged 6-19 years and weighing 420-560 kg, were used in this prospective, randomized, blinded, cross-over experimental study. Methods: After routine placement of a caudal epidural catheter, all animal...
Valverde A, Cribb N, Arroyo L.Twelve adult horses were randomly assigned to 2 groups in a prospective experimental trial. A pneumatic tourniquet (425 mmHg) was placed, under sedation, proximal to the carpus on one randomly chosen thoracic limb. A cephalic vein catheter was placed distal to the tourniquet to establish an intravenous regional limb perfusion technique (IVRLP) with morphine (0.1 mg/kg) diluted with saline 0.9% to 0.1 mL/kg, and the tourniquet left in place for 30 minutes. Horses were euthanized at 1 h (Group I) or 6 h (Group II) following the IVRLP and synovial fluid from the radiocarpal, intercarpal, metacarp...
Castro-Cuellar G, Cremer J, Liu CC, Queiroz-Williams P, Hampton C, Leise BS.To investigate the cytotoxic effects of 2 different concentrations of buprenorphine and compare them with bupivacaine and morphine on healthy equine chondrocytes in vitro. Methods: Primary cultured equine articular chondrocytes from 3 healthy adult horses. Methods: Chondrocytes were exposed for 0 and 2 hours to the following treatments: media (CON; negative control); bupivacaine at 2.2 mg/mL (BUPI; positive control); morphine at 2.85 mg/mL (MOR); buprenorphine at 0.12 mg/mL (HBUPRE); or buprenorphine at 0.05 mg/mL (LBUPRE). Chondrocyte viability was assessed using live/dead staining, water-sol...
Knych HK, Kanarr K, Fang Y, McKemie DS, Kass PH.To describe the pharmacokinetics, behavioral and physiologic effects and effects on thermal thresholds of morphine, morphine 6-glucuronide (M6G) and morphine 3-glucuronide (M3G) following administration to horses. Methods: Randomized balanced crossover study. Methods: A total of seven University-owned horses, five mares and two geldings, aged 3-6 years. Methods: Horses were treated with a single intravenous dosage of saline, morphine (0.2 mg kg), M6G (0.01 mg kg) and M3G (0.03 mg kg). Blood was collected prior to (baseline) and at several times post administration. Drug and metabolite concentr...
Alonso B, Carregaro A, Cuypers C, Michielsen A, Gasthuys F, Schauvliege S.To evaluate the effects of detomidine or romifidine on cardiovascular function, isoflurane requirements and recovery quality in horses undergoing isoflurane anaesthesia. Methods: Prospective, randomized, blinded, clinical study. Methods: A total of 63 healthy horses undergoing elective surgery during general anaesthesia. Methods: Horses were randomly allocated to three groups of 21 animals each. In group R, horses were given romifidine intravenously (IV) for premedication (80 μg kg), maintenance (40 μg kg hour) and before recovery (20 μg kg). In group D2.5, horses were given detomidine IV f...
Cock G, Blakeney Z, Hernandez JA, DeNotta S.Atlantoaxial (AA) cerebrospinal fluid (CSF) collection in standing horses utilizes the controlled narcotic morphine, thereby limiting feasibility in field practice settings. Objective: To compare AA CSF collection time and reaction scores in horses sedated with morphine-containing and opioid-free sedation protocols: detomidine + morphine (DM), detomidine + xylazine (DX), detomidine + detomidine (DD), detomidine alone (D0); To develop a novel method for assessing sedation in standing horses using open-source motion-tracking software. Methods: Six healthy adult horses. Methods: Randomi...
Knych HK, Stucker K, Gretler SR, Kass PH, McKemie DS.In humans, codeine is a commonly prescribed analgesic that produces its therapeutic effect largely through metabolism to morphine. In some species, analgesic effects of morphine have also been attributed to the morphine-6-glucuronide (M6G) metabolite. Although an effective analgesic, administration of morphine to horses produces dose-dependent neuroexcitation at therapeutic doses. Oral administration of codeine at a dose of 0.6 mg/kg has been shown to generate morphine and M6G concentrations comparable to that observed following administration of clinically effective doses of morphine, witho...
Ruíz-López P, Morgaz J, Quirós-Carmona S, Navarrete-Calvo R, Domínguez JM, Gómez-Villamandos RJ, Granados MM.Autonomic nervous system (ANS) activity can modify cardiovascular parameters in response to nociceptive stimuli or drugs in anesthetized animals. The aim of this study was to determine if a surgical nociceptive stimulus and morphine, ketamine, and dobutamine administration would modify ANS activity observed as a change in the mean parasympathetic tone activity (PTAm) in anesthetized horses. In 20 anesthetized horses, heart rate (HR), mean arterial pressure (MAP), and PTAm were monitored before and 1, 3, and 5 min after surgical incision, and before and 10 min after the administration of morphi...
Troya-Portillo L, López-Sanromán J, Villalba-Orero M, Santiago-Llorente I.Standing surgery under sedation reduces anesthetic-related mortality in horses. Medetomidine, alone and combined with morphine in a constant rate infusion (CRI), has been described for standing surgery but their cardiorespiratory, sedative and antinociceptive effects have never been compared. The addition of ketamine could improve analgesia in these procedures with minimal cardiorespiratory consequences. The objectives were to compare the cardiorespiratory effects, quality of sedation, antinociception and ataxia produced by administration of a medetomidine-based CRI with morphine, ketamine or ...
López-Sanromán FJ, Freilich GM, Gomez-Cisneros D, Varela M, Santiago I, Manso-Díaz G.The objective of the present study was to compare, using accelerometry, the gait changes produced after administration of a dose of 0.2 mg/kg of morphine at the walk in healthy horses. Six mature horses were used, and all animals received two different treatments with, at least, two weeks interval in between. Treatments administered consisted of a single dose of 10 ml of saline solution or a total of 0.2 mg/kg of morphine diluted in 10 ml of saline solution. A three-dimensional accelerometric device was used to collect data continuously while horses were walking. The walking test was performed...
Natalini CC, Paes SD, Polydoro ADS.The study aim is to compare the effects of epidural administration of two different doses of romifidine combined with morphine in horses. A prospective crossover blinded experimental design was used. Five adult healthy horses two males and three females with a mean body weight of 380 ± 45 Kg (335-425 kg), were studied. Treatments consisted of romifidine 30 μg/kg (R30) or 60 μg/kg (R60) combined with morphine 0.1 mg/kg with a washout interval of 72 hours, administered through an epidural catheter placed at the first intercoccygeal space. Heart rate (HR) and respiratory rate (f), pH, blood ga...
Fujiyama M, Jones T, Duke-Novakovski T.To evaluate perioperative stress-related hormones in isoflurane-anesthetized horses administered infusions of dexmedetomidine alone or with butorphanol or remifentanil, compared with ketamine-morphine. Methods: Randomized, prospective, nonblinded clinical study. Methods: A total of 51 horses undergoing elective surgical procedures. Methods: Horses were premedicated with xylazine, anesthesia induced with ketamine-diazepam and maintained with isoflurane and one of four intravenous infusions. Partial intravenous anesthesia (PIVA) was achieved with dexmedetomidine (1.0 μg kg hour; group D; 12 hor...
Duke-Novakovski T, Jimenez CP, Fujiyama M, Beazley SG.Various drugs administered to horses undergoing surgical procedures can release histamine. Histamine concentrations were evaluated in horses prepared for surgery and administered butorphanol or morphine intraoperative infusions. Methods: Prospective studies with one randomized. Methods: A total of 44 client-owned horses. Methods: In one study, anesthesia was induced with xylazine followed by ketamine-diazepam. Anesthesia was maintained with guaifenesin-xylazine-ketamine (GXK) during surgical preparation. For surgery, isoflurane was administered with intravenous (IV) morphine (group M: 0.15 mg ...
de Oliveira MGC, Luna SPL, Nunes TL, Firmino PR, de Lima AGA, Ferreira J, Trindade PHE, Júnior RAB, de Paula VV.Recognising pain in donkeys is challenging because they are stoic. Objective: To identify the responses of donkeys before and after surgical pain. Methods: Prospective, short-term longitudinal pre- and post-intervention observations. Methods: Forty adult donkeys underwent surgical castration after sedation with intravenous (IV) xylazine, induction with guaiphenesin/thiopental IV and maintenance of anaesthesia with isoflurane and local anaesthetic blockade. Four hours after recovery from anaesthesia, flunixin meglumine 1.1 mg/kg, dipyrone 10 mg/kg and morphine 0.2 mg/kg IV were administered....
Delli-Rocili MM, Cribb NC, Trout DR, Thomason JJ, Valverde A.To compare the effectiveness of a paravertebral nerve block vs local portal blocks for laparoscopic closure of the nephrosplenic space in standing sedated research horses. Methods: Randomized clinical trial. Methods: Twelve horses were randomly allocated to two groups (n = 6 per group), paravertebral block of nerves T , L , and L or local blocks of the three laparoscopic portals. Methods: Horses were sedated with dexmedetomidine (4 μg/kg IV and constant rate infusion [CRI] of 2.5 μg/kg/h) and morphine (50 μg/kg IV and CRI of 30 μg/kg/h). According to group allocation, 20 mL of either lid...
Gretler SR, Finno CJ, McKemie DS, Kass PH, Knych HK.To describe the pharmacokinetics and selected pharmacodynamic variables of codeine and its metabolites in Thoroughbred horses following a single oral administration. Methods: Prospective experimental study. Methods: A total of 12 Thoroughbred horses, nine geldings and three mares, aged 4-8 years. Methods: Horses were administered codeine (0.6 mg kg) orally and blood was collected before administration and at various times until 120 hours post administration. Plasma and urine samples were collected and analyzed for codeine and its metabolites by liquid chromatography-mass spectrometry, and plas...
Mirra A, Birras J, Diez Bernal S, Spadavecchia C.Epidural administration of morphine has been shown to be an effective analgesic strategy in horses; however, the possible occurrence of side effects limits its usage. In order to decrease their frequency, it is important to target the minimal effective plasma concentration and avoid overdosing. As to date species-specific pharmacokinetics data are not available for epidural morphine, the dosing regimen is usually established on the basis of clinical reports and personal experience. In certain physiological conditions, like gestation, the outcome of an empirical dosing scheme can be unpredictab...
Tessier C, Pitaud JP, Thorin C, Touzot-Jourde G.There are no data investigating the effect of systemic morphine on the size of the stomach or the food consumption in horses. Objective: To evaluate gastrointestinal side effects of morphine administered systemically in healthy horses by the means of clinical and ultrasonographic evaluations. Methods: In vivo experiment. Methods: On day 1 of the experiment, six healthy French Trotter mares were evaluated clinically and an abdominal ultrasonography was performed three times 4 h apart to record the size of the stomach, the number of contractions per minute of the duodenum, jejunum, caecum, left...
Schwarzbach SV, Melo CF, Xavier PLP, Roballo KC, Cordeiro YG, Ambrósio CE, Fukumasu H, Carregaro AB.Osteoarthritis (OA) is one of the main locomotor disorders in horses. Although nonsteroidal anti-inflammatory drugs are the first-line treatment for OA, opioids could also be used. In previous studies, opioids showed promising anti-inflammatory and analgesic effects. In this study, we aimed to investigate the effects of two opioids (morphine and methadone) against inflammation in lipopolysaccharide (LPS)-stimulated synoviocytes by analyzing microsomal prostaglandin E synthase-1 (mPGES-1) and prostaglandin-endoperoxide synthase 2 (PTGS2) expression. Synoviocytes were obtained from the joints at...
Rowland AL, Glass KG, Grady ST, Cummings KJ, Hinrichs K, Watts AE.To determine the influence of epidural detomidine and morphine on serum corticosteroid concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy. Methods: Blinded prospective study. Methods: Nine university-owned mares. Methods: Five of 9 horses received caudal epidural detomidine hydrochloride (0.01 mg/kg) and morphine sulfate (0.1 mg/kg) prior to surgery. All horses received local anesthetic around the ovarian pedicle, 0.02 mg/kg butorphanol IV at the start of the procedure and after first ovary removal, were sedated as required throughout the p...
Abass M, Picek S, Garzón JFG, Kühnle C, Zaghlou A, Bettschart-Wolfensberger R.In horses castration with primary intention healing is usually performed under balanced inhalation anaesthesia. To optimise analgesia, the use of local anaesthesia was tested. Objective: To investigate the effect of local mepivacaine before castration with first intention healing under balanced medetomidine-isoflurane anaesthesia and flunixin meglumine, morphine analgesia on perioperative cytokine levels and pain in horses. Methods: Prospective blinded clinical study. Methods: Twenty stallions were randomly assigned to control or mepivacaine groups. Flunixin meglumine was administered before s...
Rubio-Martínez LM, Rioja E, Castro Martins M, Wipawee S, Clegg P, Peffers MJ.Chondrotoxic effects of local anaesthetics are well reported in humans and some animal species but knowledge on their toxic effects on synoviocytes or equine chondrocytes or the effects on cellular production of inflammatory cytokines is limited. The purpose of this study was to evaluate the in vitro effects of local anaesthetics, morphine, magnesium sulphate (MgSO4) or their combinations on cell viability and pro-inflammatory cytokine gene expression of equine synoviocytes and chondrocytes. Equine synoviocytes and cartilage explants harvested from normal joints in a co-culture system were exp...
Santangelo B, Robin A, Simpson K, Potier J, Guichardant M, Portier K.Xenon, due to its interesting anesthetic properties, could improve the quality of anesthesia protocols in horses despite its high price. This study aimed to modify and test an anesthesia machine capable of delivering xenon to a horse. Methods: An equine anesthesia machine (Tafonius, Vetronic Services Ltd., UK) was modified by including a T-connector in the valve block to introduce xenon, so that the xenon was pushed into the machine cylinder by the expired gases. A xenon analyzer was connected to the expiratory limb of the patient circuit. The operation of the machine was modeled and experimen...
Herholz C, Zink N, Laska H, Gumpendobler M, Trolliet C, Probst S.Horse feed material of Swiss and foreign production available on the Swiss market was tested with regard to possible contamination with 7 different alkaloids, atropine and colchicine. Twenty-eight feed samples as well as 2 poppy seed samples were analyzed. Out of 28 feed samples 18 were positive for prohibited substances in Equestrian sports. The concentration of prohibited substances was in none of the samples high enough to cause an effect on the body of the horse. The poppy seed sample, which was obtained by conventional harvesting and cleaning methods, contained a very high Morphine concen...
Conde Ruiz C, Cruz Benedetti IC, Guillebert I, Portier KG.This prospective blinded randomized study aimed to determine whether the timing of morphine and phenylbutazone administration affects the breathing response to skin incision, recovery quality, behavior, and cardiorespiratory variables in horses undergoing fetlock arthroscopy. Ten Standardbred horses were premedicated with acepromazine (0.04 mg kg(-1) IM) and romifidine (0.04 mg kg(-1) IV). Anesthesia was induced with diazepam (0.05 mg kg(-1)) and ketamine (2.2 mg kg(-1)) IV at T0. Horses in group PRE (n = 5) received morphine (0.1 mg kg(-1)) and phenylbutazone (2.2 mg kg(-1)) I...
Potter JJ, MacFarlane PD, Love EJ, Tremaine H, Taylor PM, Murrell JC.To compare sedative and analgesic properties of buprenorphine or morphine for standing procedures combined with a detomidine continuous rate infusion (CRI). Methods: Blinded, prospective, randomized clinical pilot study. Methods: Ten horses presented for dental or sinus procedures. Methods: Horses received 0.02 mg kg(-1) acepromazine intravenously (IV), followed 30 minutes later by detomidine 10 μg kg(-1) IV. Five minutes later, buprenorphine 0.01 mg kg(-1) (n = 6) or morphine 0.1 mg kg(-1) (n = 4) was administered IV. Detomidine was administered by CRI (0.2 μg kg(-1) minute(-1)) and adjuste...
Carregaro AB, Freitas GC, Ribeiro MH, Xavier NV, Dória RG.Continuous-rate infusion (CRI) of drugs results in more stable plasma drug concentrations than administration of intermittent boluses, thus providing greater stability of physiological parameters. The aim of this study was to evaluate the physiologic and analgesic effects of the administration of morphine, butorphanol, tramadol or methadone by CRI in horses with induced synovitis of the radiocarpal joint. Results: Increased values of cardiorespiratory parameters and body temperature were observed in all groups after initiation of opioid administration, and these increases were sustained throug...
Lindegaard C, Thomsen MH, Larsen S, Andersen PH.To compare the analgesic effect of intra-articular (IA) and intravenous (IV) morphine in horses with experimentally induced synovitis. Methods: Eight adult horses. Methods: Randomized, observer blinded, double dummy trial with sequential crossover design. Methods: Radiocarpal synovitis was induced by IA injection of lipopolysaccharide on two occasions separated by a 3-week washout period. In one study period horses received treatment IA; morphine IA (0.05 mg kg(-1)) plus saline IV and in the other study period they received treatment IV; saline IA plus morphine IV (0.05 mg kg(-1)). Lameness an...
Boscan P, Van Hoogmoed LM, Farver TB, Snyder JR.To evaluate the effects of morphine administration for 6 days on gastrointestinal tract function in healthy adult horses. Methods: 5 horses. Methods: Horses were randomly allocated into 2 groups in a crossover study. Horses in the treatment group received morphine sulfate at a dosage of 0.5 mg/kg, IV, every 12 hours for 6 days. Horses in the control group received saline (0.9% NaCl) solution at a dosage of 10 mL, IV, every 12 hours for 6 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (evaluated by use of barium-filled spheres and radio...
Natalini CC, Robinson EP.To evaluate and compare effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H on avoidance threshold to noxious electrical stimulation over the dermatomes of the perineal, sacral, lumbar, and thoracic regions in horses. Methods: 5 healthy adult horses. Methods: Using a Latin square complete repeated-measures design, horses were randomly assigned to receive 1 of 6 treatments (morphine, alfentanil, butorphanol, tramadol, U50488H, or sterile water) at intervals of at least 7 days. Agents were injected epidurally at the first intercoccygeal epidural space, and...
Lindegaard C, Gleerup KB, Thomsen MH, Martinussen T, Jacobsen S, Andersen PH.To compare the effects of intra-articular (IA) versus IV administration of morphine on local and systemic inflammatory responses in horses with experimentally induced acute synovitis. Methods: 8 horses. Methods: Each horse received the following 2 treatments 4 hours after synovitis was induced: IA administration of morphine (0.05 mg/kg) with IV administration of 1 mL of saline (0.9% NaCl) solution/100 kg, and IA administration of 1 mL of saline solution/100 kg with IV administration of morphine (0.05 mg/kg). Treatments were administered in randomized order with a washout period of 3 weeks betw...
Solano AM, Valverde A, Desrochers A, Nykamp S, Boure LP.Standing surgical procedures are performed commonly in horses under sedation. This approach minimises the morbidity/mortality risks associated with general anaesthesia. The use of a medetomidine and morphine combination has not been investigated in horses despite the usefulness of each drug individually. Objective: To determine the efficacy of a medetomidine and morphine combination to produce standing sedation with minimal cardiorespiratory changes and adequate analgesia for exploratory laparascopy in mature horses. Objective: The combination of medetomidine and morphine will induce reliable ...
Gozalo-Marcilla M, Gasthuys F, Schauvliege S.To review the literature with regard to the use of different intravenous agents as supplements to inhalational anaesthesia in horses. The Part 2 of this review will focus in the use of opioids and α2 -agonists. Methods: Pubmed and Web of Science. Search terms: horse, inhalant anaesthesia, balanced anaesthesia, partial intravenous anaesthesia, opioids, morphine, pethidine, butorphanol, methadone, fentanyl, alfentanil, remifentanil, sufentanil, xylazine, romifidine, detomidine, medetomidine and dexmedetomidine. Conclusions: Different drugs and their combinations can be administered systemically...
Kalpravidh M, Lumb WV, Wright M, Heath RB.The analgesic and behavioral effects of butorphanol (0.22 mg/kg), flunixin (2.2 mg/kg), levorphanol (0.033 mg/kg), morphine (0.66 mg/kg), and xylazine (2.2 mg/kg), given IM were observed in 8 ponies. These ponies were instrumented to measure response objectively to painful superficial and visceral stimuli. Effects on the cardiopulmonary system and rectal temperature also were evaluated in 6 of these ponies. Observations were conducted before drug injection (base-line values) and after injection at 30, 60, 120, 180, and 240 minutes. Xylazine provided the highest pain threshold for the first 60 ...
Steffey EP, Eisele JH, Baggot JD.To quantitate dose- and time-related magnitudes of interactive effects of morphine (MOR) and isoflurane (ISO) in horses and to characterize pharmacokinetics of MOR in plasma and the ventilatory response to MOR during administration of ISO. Methods: 6 adult horses. Methods: Horses were anesthetized 3 times to determine the minimum alveolar concentration (MAC) of ISO in O2 and then to characterize the change in anesthetic requirement as defined by the alteration in ISO MAC following IV administration of saline (0.9% NaCl) solution and 2 doses of MOR (low dose, 0.25 mg/kg; high dose, 2.0 mg/kg). ...
Goodrich LR, Nixon AJ, Fubini SL, Ducharme NG, Fortier LA, Warnick LD, Ludders JW.To determine whether preoperative epidural administration of morphine and detomidine would decrease postoperative lameness after bilateral stifle arthroscopy in horses. Methods: Prospective clinical controlled study. Methods: Eight adult horses that had bilateral arthroscopic procedures, including drilling of cartilage and subchondral bone within the femoropatellar joints. Methods: Horses were randomly separated into 2 groups. Preoperatively, 4 horses were administered a combination of epidural morphine (0.2 mg/kg) and detomidine (30 microg/kg), and 4 horses were administered an equivalent vol...
Mircica E, Clutton RE, Kyles KW, Blissitt KJ.To identify the incidence of adverse effects caused by morphine 100-170 micro g kg-1 administration during surgery in horses. Methods: Retrospective case record analysis (1996-2000). Methods: Eighty-four healthy (ASA 1 or 2) horses, mean age 5.5 +/- 3.1 (SD) years (2 months to 16 years), mean weight 524 +/- 14 kg (100-950). Methods: Physiological data and evidence of complications were collected from the anaesthetic records of all animals anaesthetized with romifidine, ketamine, diazepam and halothane and undergoing laryngeal surgery or orchiectomy at the Royal (Dick) School of Veterinary Stud...
Santos LC, de Moraes AN, Saito ME.To compare the intraarticular (IA) analgesic effects of ropivacaine and morphine in horses with experimentally induced synovitis. Methods: Randomized, blinded cross-over design. Methods: Twelve healthy mixed breed horses between 8-15 years old. Methods: Synovitis was induced in the left radio-carpal joint with an injection of lipopolysaccharide (Escherichia coli 055:B5). Six hours later, the horses were treated with an IA injection of 40 mg of ropivacaine (ROPI), 40 mg of morphine (MOR), 20 mg of ropivacaine added to 20 mg of morphine in saline (RM) or 4 mL of saline (SAL), as control. Analges...
Gozalo-Marcilla M, Steblaj B, Schauvliege S, Duchateau L, Gasthuys F.Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinded, clinical study. Horses were randomly allocated to receive a constant rate infusion (CRI) of morphine or dexmedetomidine. After induction, anaesthesia was maintained with isoflurane in oxygen/air and mechanical ventilation applied. The end-tidal isoflurane concentration (FÉISO) was initially set at 0.9% and adjusted by the anaesthetist, to maintain a light surgical plane of anaesthesia, according to an objective flow-chart. The cardiopulmonary function was only minimally different between groups...
Hamra JG, Kamerling SG, Wolfsheimer KJ, Bagwell CA.Diurnal variation in nociceptive sensitivity and plasma immunoreactive beta-endorphin (ir-BEND) concentrations was examined in eight healthy Thoroughbred horses. Pain thresholds, ir-BEND concentrations, rectal temperature, heart rate, respiratory rate and pupil diameter were measured over a 24 hour period. Nociceptive sensitivity was determined using two objective measures of pain: the skin-twitch reflex latency and the hoof withdrawal reflex latency. Significant variation in both nociceptive thresholds and ir-BEND concentrations were noted over the 24 hour period, with elevated pain threshold...
Corletto F, Raisis AA, Brearley JC.The aim of this study was to compare two different alpha2 agonist-opioid combinations in ponies undergoing field castration. Methods: Prospective double-blind randomized clinical trial. Methods: Fifty-four ponies undergoing field castration. Methods: The ponies were randomly allocated to receive one of three different pre-anaesthetic medications [intravenous (IV) romifidine 100 microg kg(-1) and butorphanol 50 micro kg(-1); romifidine 100 microg kg(-1) and morphine 0.1 mg kg(-1) IV, or romifidine 100 microg kg(-1) and saline IV] before induction of anaesthesia with ketamine 2.2 mg kg(-1) IV. F...
Muir WW, Skarda RT, Sheehan WC.The cardiopulmonary effects of the narcotic agonists morphine, meperidine, oxymorphone, and methadone and of the partial agonist pentazocine were examined in the pain-free adult horse. The drugs produced dysphoric followed by euphoric effects. Increases in heart rate, arterial blood pressure, and cardiac output were observed in all horses with all drugs. Arterial blood pressure remained increased even after heart rate and cardiac output had returned to base-line values. Respiratory rate generally remained unchanged or increased shortly after drug administration and then decreased insignificant...
Abass M, Picek S, Garzón JFG, Kühnle C, Zaghlou A, Bettschart-Wolfensberger R.In horses castration with primary intention healing is usually performed under balanced inhalation anaesthesia. To optimise analgesia, the use of local anaesthesia was tested. Objective: To investigate the effect of local mepivacaine before castration with first intention healing under balanced medetomidine-isoflurane anaesthesia and flunixin meglumine, morphine analgesia on perioperative cytokine levels and pain in horses. Methods: Prospective blinded clinical study. Methods: Twenty stallions were randomly assigned to control or mepivacaine groups. Flunixin meglumine was administered before s...
Villalba M, Santiago I, Gomez de Segura IA.Lidocaine and ketamine are administered to horses as a constant rate infusion (CRI) during inhalation anaesthesia to reduce anaesthetic requirements. Morphine decreases the minimum alveolar concentration (MAC) in some domestic animals; when administered as a CRI in horses, morphine does not promote haemodynamic and ventilatory changes and exerts a positive effect on recovery. Isoflurane-sparing effect of lidocaine, ketamine and morphine coadministration has been evaluated in small animals but not in horses. Objective: To determine the reduction in isoflurane MAC produced by a CRI of lidocaine ...
Sysel AM, Pleasant RS, Jacobson JD, Moll HD, Modransky PD, Warnick LD, Sponenberg DP, Eyre P.Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 micrograms/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural...
Kohn CW, Muir WW.Comparison of the visceral analgesic effects of xylazine, morphine, butorphanol, pentazocine, meperidine, dipyrone, and flunixin in a cecal distention model of colic pain indicated that xylazine produces the most relief from abdominal discomfort. Repeated administration of xylazine may reduce visceral pain so effectively that the seriousness of abdominal disease is obscured. Xylazine decreased propulsive motility in the jejunum and pelvic flexure of healthy ponies. Morphine and butorphanol also gave relief from visceral pain in the cecal distention model. Morphine may inhibit colonic, and buto...
Natalini CC, Robinson EP.Heart rate, arterial blood pressures, respiratory rate, body temperature, and central nervous system excitement were compared before and after epidural administration of morphine (0.1 mg/kg), butorphanol (0.08 mg/kg), alfentanil (0.02 mg/kg), tramadol (1.0 mg/kg), the k-opioid agonist U50488H (0.08 mg/kg), or sterile water using an incomplete Latin square crossover design in five conscious adult horses. Treatments were administered into the first intercoccygeal epidural space. Significant (P <.05) reductions in respiratory rate were detected after epidural administration of morphine, alfent...
Clark L, Clutton RE, Blissitt KJ, Chase-Topping ME.To study the effects of morphine on haemodynamic variables, blood gas values and the requirement for additional anaesthetic drugs in horses undergoing surgery. Methods: Prospective randomized study. Methods: Thirty-eight client-owned horses, ASA(American Society of Anesthesiologists) category I or II, undergoing elective surgical procedures, were studied. Horses were divided between two groups, and were paired according to operation, anaesthetist, body position during surgery, mass and breed. Group M+ received morphine by intravenous (IV) injection (0.15 mg kg(-1)) before induction of anaesthe...
Freitas GC, Carregaro AB, Gehrcke MI, De La Côrte FD, Lara VM, Pozzobon R, Brass KE.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 lipopol...
Muir WW, Skarda RT, Sheehan WC.The cardiopulmonary effects of two xylazine-morphine sulfate drug combinations (mixtures) given IV were evaluated in horses. In horses given xylazine (0.66 mg/kg of body weight) and morphine sulfate (0.12 mg/kv) IV (experiment 1), there were significant (P less than 0.05) decreases in heart rate, cardiac output, and respiratory rate. Central venous pressure was significantly (P less than 0.05) increased. Arterial and pulmonary arterial blood pressures increased significantly (P less than 0.05) but transiently. Arterial blood gas tensions (PaCO2 and PaO2) and pH remained unchanged. In the horse...
Van Hoogmoed LM, Galuppo LD.To evaluate use of ENDO-GIA staples and ENDO-Catch pouches for ovariectomy in mares and to evaluate the efficacy of epidural morphine analgesia. Methods: Randomized clinical trial. Methods: Mares (n = 10) with normal ovaries. Methods: An Endo-GIA II stapler (United States Surgical Corp., Norwalk, CT) was used to amputate the ovaries bilaterally, in standing mares, and Endo-Catch II pouches (United States Surgical Corp.) were used for retrieval. Epidural morphine was used in 5 mares, and procedure duration, volume of lidocaine required to desensitize the ovarian pedicle, and sedation were compa...
Carregaro AB, Freitas GC, Ribeiro MH, Xavier NV, Dória RG.Continuous-rate infusion (CRI) of drugs results in more stable plasma drug concentrations than administration of intermittent boluses, thus providing greater stability of physiological parameters. The aim of this study was to evaluate the physiologic and analgesic effects of the administration of morphine, butorphanol, tramadol or methadone by CRI in horses with induced synovitis of the radiocarpal joint. Results: Increased values of cardiorespiratory parameters and body temperature were observed in all groups after initiation of opioid administration, and these increases were sustained throug...
Fischer BL, Ludders JW, Asakawa M, Fortier LA, Fubini SL, Nixon AJ, Radcliffe RM, Erb HN.To compare the analgesic efficacy of buprenorphine plus detomidine with that of morphine plus detomidine when administered epidurally in horses undergoing bilateral stifle arthroscopy. Methods: Prospective, randomized, blinded clinical trial. Methods: Twelve healthy adult horses participating in an orthopedic research study. Group M (n = 6) received morphine (0.2 mg kg(-1)) and detomidine (0.15 mg kg(-1)) epidurally; group B (n = 6) received buprenorphine (0.005 mg kg(-1)) and detomidine (0.15 mg kg(-1)) epidurally. Methods: Horses received one of two epidural treatments following induction of...
Natalini CC, Paes SD, Polydoro ADS.The study aim is to compare the effects of epidural administration of two different doses of romifidine combined with morphine in horses. A prospective crossover blinded experimental design was used. Five adult healthy horses two males and three females with a mean body weight of 380 ± 45 Kg (335-425 kg), were studied. Treatments consisted of romifidine 30 μg/kg (R30) or 60 μg/kg (R60) combined with morphine 0.1 mg/kg with a washout interval of 72 hours, administered through an epidural catheter placed at the first intercoccygeal space. Heart rate (HR) and respiratory rate (f), pH, blood ga...
Conde Ruiz C, Cruz Benedetti IC, Guillebert I, Portier KG.This prospective blinded randomized study aimed to determine whether the timing of morphine and phenylbutazone administration affects the breathing response to skin incision, recovery quality, behavior, and cardiorespiratory variables in horses undergoing fetlock arthroscopy. Ten Standardbred horses were premedicated with acepromazine (0.04 mg kg(-1) IM) and romifidine (0.04 mg kg(-1) IV). Anesthesia was induced with diazepam (0.05 mg kg(-1)) and ketamine (2.2 mg kg(-1)) IV at T0. Horses in group PRE (n = 5) received morphine (0.1 mg kg(-1)) and phenylbutazone (2.2 mg kg(-1)) I...
Benmansour P, Husulak ML, Bracamonte JL, Beazley SG, Withnall E, Duke-Novakovski T.To examine the cardiopulmonary effects of infusions of remifentanil or morphine, and their influence on recovery of horses anesthetized with isoflurane and dexmedetomidine. Methods: Randomized crossover study with 7-day rest periods. Methods: Six adult horses (507 ± 61 kg). Methods: After the horses were sedated with xylazine, anaesthesia was induced with ketamine and diazepam, and maintained with isoflurane. After approximately 60 minutes, a dexmedetomidine infusion was started (0.25 μg kg(-1) then 1.0 μg(-1) kg(-1) hour(-1) ) in combination with either saline (group S), morphine (0.15 mg ...
