Pharmacology in horses involves the study and application of drugs and medications to diagnose, treat, and prevent diseases and conditions in equine species. This field encompasses the understanding of pharmacokinetics and pharmacodynamics specific to horses, including how drugs are absorbed, distributed, metabolized, and excreted by the equine body. Commonly studied pharmacological agents in horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, sedatives, and anthelmintics. Research in equine pharmacology focuses on determining appropriate dosages, understanding drug interactions, and minimizing adverse effects. This page compiles peer-reviewed research studies and scholarly articles that investigate the efficacy, safety, and regulatory aspects of pharmacological interventions in equine veterinary practice.
Weber LA, Puff C, Kalbitz J, Kietzmann M, Feige K, Bosse K, Rohn K, Cavalleri JV.The naturally occurring betulinic acid (BA) and its derivative NVX-207 show anticancer effects against equine malignant melanoma (EMM) cells and a potent permeation in isolated equine skin in vitro. The aim of the study was to determine the in vivo concentration profiles of BA and NVX-207 in equine skin and assess the compounds' local and systemic tolerability with the intent of developing a topical therapy against EMM. Eight horses were treated percutaneously in a crossover design with 1% BA, 1% NVX-207 or a placebo in a respective vehicle twice a day for seven consecutive days with a seven-d...
Machin J, Childers T, Kudrimoti S, Eisenberg R, Fenger C, Hartmann P, Maylin G, Shults T, Tobin T.Aminorex is a US DEA Schedule 1 controlled substance occasionally detected in racing horses. A number of aminorex identifications in sport horses were thought to have been caused by exposure to plant sources of aminorex. Glucobarbarin, found in plants of the Brassicaceae family, has been suggested as a potential proximate chemical source by being metabolized in the plant or the horse to aminorex. In Brassicaceae, glucobarbarin is hydrolyzed by myrosinase to yield barbarin, which serves as an insect repellant and/or attractant and is structurally related to aminorex. The synthesis, purification...
Shihadih DS, Harris TR, Kodani SD, Hwang SH, Lee KSS, Mavangira V, Hamamoto B, Guedes A, Hammock BD, Morisseau C.The veterinary pharmacopeia available to treat pain and inflammation is limited in number, target of action and efficacy. Inhibitors of soluble epoxide hydrolase (sEH) are a new class of anti-inflammatory, pro-resolving and analgesic drugs being tested in humans that have demonstrated efficacy in laboratory animals. They block the hydrolysis, and thus, increase endogenous concentrations of analgesic and anti-inflammatory signaling molecules called epoxy-fatty acids. Here, we screened a library of 2,300 inhibitors of the sEH human against partially purified feline, canine and equine hepatic sEH...
Malacarne BD, Cota LO, Neto ACP, Paz CFR, Dias LA, Corrêa MG, Carvalho AM, Faleiros RR, Xavier ABS.With the hypothesis that equine dorsal lamellar tissue can be desensitized by anesthesia injection into distal interphalangeal joint (DIPJ), the objective was to assess the mechanical nociceptive threshold of hoof dorsal lamellae following intra-articular (IA) administration of lidocaine into this joint. Methods: The DIPJ of the forelimbs of six adult healthy horses were injected with either 5 mL of lidocaine, or 5 mL of lactated Ringer's solution. Treatments were randomly distributed, with each forelimb undergoing a single treatment. The hooves were evaluated pre- and post-injection at pre-se...
Zitterl-Eglseer K, Marschik T.Viruses have a high mutation rate, and, thus, there is a continual emergence of new antiviral-resistant strains. Therefore, it becomes imperative to explore and develop new antiviral compounds continually. The search for pharmacological substances of plant origin that are effective against animal viruses, which have a high mortality rate or cause large economic losses, has garnered interest in the last few decades. This systematic review compiles 130 plant species that exhibit antiviral activity on 37 different virus species causing serious diseases in animals. The kind of extract, fraction, o...
Oberhaus EL, Thompson DL, Kerrigan LE, Chapman AM.Stress or excitement is a concern when performing endocrine tests on fractious horses. Sedation may be a solution; however, perturbation of test results may preclude useful information. Thyrotropin-releasing hormone (TRH) is a known stimulator of prolactin, thyroid-stimulating hormone (TSH), melanocyte-stimulating hormone (MSH), and ACTH. Thyrotropin-releasing hormone-induced ACTH is a diagnostic tool for the assessment of endocrinopathies such as pituitary pars intermedia dysfunction. It is unknown if drugs commonly used for sedation alter endocrine responses. The objective of this study was ...
Grady SE, Lescun TB, Moore GE, Cooper BR, Davern AJ, Brunner TJ, Taylor SD.The objective was to compare the analgesic efficacy of ketorolac tromethamine (KT) and two other nonsteroidal anti-inflammatory drugs (NSAIDs), including flunixin meglumine (FM) and phenylbutazone (PB), using a heart bar shoe (HBS) model of reversible foot lameness in horses. Nine adult horses were used in a blinded, randomized, placebo-controlled crossover study. After induction of left front limb lameness using a modified HBS model, one of three NSAIDs (KT, 2.0 mg/kg IV; FM, 1.1 mg/kg IV; PB, 4.4 mg/kg IV) or saline (placebo) was administered IV as a single dose. Lameness was assessed eve...
Sullivan SN, Altmann NN, Brokken MT, Durgam SS.Primary deep digital flexor tendon (DDFT) pathologies and those accompanying degenerative changes of navicular bone fibrocartilage are major causes of lameness associated with navicular disease. Intrasynovial corticosteroids are mainstay in the treatment due to the anti-inflammatory effects, but their effect on DDFT cell biosynthesis are unknown. The objective of this study was to investigate the effects of methylprednisolone acetate (MPA) on cells isolated from the dorsal fibrocartilaginous region of forelimb DDFTs (DDFT-derived cells) of 5 horses (aged 11-17 years). Non-adherent aggregate c...
Rahnama S, Spence R, Vathsangam N, Baskerville CL, Bailey SR, de Laat MA, Anderson ST, Pollitt CC, Sillence MN.Although it is understood that equine endocrinopathic laminitis can be triggered by high concentrations of insulin, it is unclear whether this represents a direct action on lamellar tissue via insulin receptors (InsR), an interaction with IGF-1 receptors (IGF-1R), or some other, indirect action. This uncertainty is because of the reported scarcity of InsR in lamellar tissue and the low affinity of insulin for equine IGF-1R. In the present study, the effects of insulin and IGF-1 (as a positive control) were examined using lamellar explants isolated from the hooves of healthy horses and incubate...
Miller AB, Loynachan AT, Bush HM, Hart KA, Barker VD, Campana-Emard AG, Grubbs ST, Adams AA.It remains unclear how pituitary pars intermedia dysfunction (PPID) and pergolide treatment (Prascend [pergolide tablets]) affect endocrine and immune function in horses. To evaluate these effects, blood was collected regularly from 28 university-owned horses (10 Non-PPID, 9 PPID control [PC], and 9 PPID treatment [PT]) over approximately 15 mo. Pergolide treatment was initiated after Day 0 collections. Analyses included ACTH, insulin, total cortisol, free cortisol, complete blood counts, plasma myeloperoxidase, and cytokine/receptor gene expression in basal whole blood and in vitro stimulat...
Skrzypczak H, Reed R, Barletta M, Quandt J, Sakai D.To describe the incidence of postanesthetic signs of colic (PASC) in horses and determine if perianesthetic administration of hydromorphone was associated with an increased risk of PASC. Methods: Retrospective, cohort study. Methods: A total of 409 horses. Methods: Anesthesia and clinical records of horses admitted for various procedures from July 2018 to September 2019 were reviewed. Signs of colic and interventions were recorded up to 48 hours after anesthesia. A binomial logistic regression model was used to evaluate the association between the type of surgery, administration of hydromorpho...
Bauquier J, Tudor E, Bailey S.Doramapimod, a p38 MAPK inhibitor, is a potent anti-inflammatory drug that decreases inflammatory cytokine production in equine whole blood in vitro. It may have benefits for treating systemic inflammation in horses. Objective: To determine whether doramapimod is well tolerated when administered IV to horses, and whether it has anti-inflammatory effects in horses in a low-dose endotoxemia model. Methods: Six Standardbred horses. Methods: Tolerability study, followed by a blinded, randomized, placebo-controlled cross-over study. Horses were given doramapimod, and clinical and clinicopathologica...
Dedar RK, Kumar N, Narnaware SD, Tripathi BN.Wound healing in horses is complicated by the excessive growth of granulation tissue, commonly known as proud flesh and is similar to keloids in human beings. At present, there is no satisfactory treatment for proud flesh in horses. In this study, we, for the first time, demonstrated that leaf extract of Aerva javanica suppresses excessive growth of granulation tissue in horses. Many plant flavonoids are claimed to have antiproliferative properties. Kaempferol is a natural flavonoid containing 3-hydroxy flavone backbone found in many plants in its aglycone form and attached with various sugars...
Chan GHM, Tang W, Curl P, Lin Y, Wan TSM, Ho ENM.Arsenic can be easily found in our surrounding environment. Because of its ubiquitous nature, horse urine and blood invariably contain low levels of arsenic. Nevertheless, inorganic arsenic, despite its general use as a tonic for horses, is an effective doping agent having a deleterious effect because of its ability to induce gastroenteritis. The misuse of arsenic in horseracing has been controlled by an international urinary threshold of total arsenic at 0.3 μg/mL. However, an equivalent threshold for total arsenic in plasma is yet to be established. In this study, an inductively coupled pla...
Ellerbrock RE, Canisso IF, Larsen RJ, Garrett KS, Stewart MC, Herzog KK, Kersh ME, Moshage SG, Podico G, Lima FS, Childs BA.Recent studies have shown that fluoroquinolones, specifically, enrofloxacin and its active metabolite (ciprofloxacin), cross the equine placenta without causing gross or histological lesions in the first and third trimester fetuses or resulting foal. However, it is possible that in utero exposure to fluoroquinolones may cause subtle lesions not detectable by standard means; thus, a more in-depth assessment of potential toxicity is warranted. Objective: To use quantitative magnetic resonance imaging (qMRI), biomechanical testing, and chondrocyte gene expression to evaluate the limbs of foals ex...
Toishi Y, Tsunoda N, Kirisawa R.In 2017, two Thoroughbred stallions, A and B in Farms A and B, respectively, in Hokkaido in Japan showed clinical signs of equine coital exanthema (ECE). In 2020, stallion C in Farm B showed clinical signs of ECE. Eighteen mares were mated within five days before stallion A developed ECE. Ten mares that mated within 3 days before onset showed clinical signs of ECE on the external genitalia. Equine herpesvirus 3 (EHV-3) was isolated from vaginal swabs from three mares that mated within 2 days before onset. Swabs from 12 mares that mated within 4 days before onset were real-time PCR (rPCR)-posit...
Martin F, Dube F, Karlsson Lindsjö O, Eydal M, Höglund J, Bergström TF, Tydén E.Parascaris univalens is a pathogenic parasite of foals and yearlings worldwide. In recent years, Parascaris spp. worms have developed resistance to several of the commonly used anthelmintics, though currently the mechanisms behind this development are unknown. The aim of this study was to investigate the transcriptional responses in adult P. univalens worms after in vitro exposure to different concentrations of three anthelmintic drugs, focusing on drug targets and drug metabolising pathways. Methods: Adult worms were collected from the intestines of two foals at slaughter. The foals were natu...
Chiocchetti R, Rinnovati R, Tagliavia C, Stanzani A, Galiazzo G, Giancola F, Silva M, Capodanno Y, Spadari A.Growing evidence recognises cannabinoid receptors as potential therapeutic targets for pain. Consequently, there is increasing interest in developing cannabinoid receptor agonists for treating pain. As a general rule, to better understand the actions of a drug, it would be of extreme importance to know the cellular distribution of its specific receptors. The localisation of cannabinoid receptors in the dorsal root ganglia of the horse has not yet been investigated. Objective: To localise the cellular distribution of canonical and putative cannabinoid receptors in the equine cervical dorsal roo...
Pezzanite L, Chow L, Piquini G, Griffenhagen G, Ramirez D, Dow S, Goodrich L.Intra-articular (IA) antibiotic usage is prevalent in equine practice. However, recent emergence of antimicrobial resistance prompts re-evaluation of antibiotic selection, particularly when used prophylactically. Furthermore, many commonly used antibiotics exert direct cytotoxicity to equine cells, and appropriate IA doses have not been defined. Objective: To screen antibiotics in vitro as an initial assessment of cytotoxicity against normal equine joint cells in monolayer culture and explant tissues. Methods: In vitro experimental study. Methods: Chondrocytes and synovial cells were harvested...
Ocampo L, Coello M, Aquino I.The aim of this study was to compare the effects of cisapride and tegaserod on intestinal smooth muscle activity in equines. Efficacy was evaluated through measurement of gastrointestinal transit time, bowel movements per day, stool weight, and bowel sounds. Drug safety was evaluated via heart rate, respiratory rate, and rectal temperature. Records were obtained throughout three periods: a control phase without treatment, a period of cisapride administration at a dose of 0.22 mg/kg, and a period of tegaserod treatment at a dose of 0.27 mg/kg. Gastrointestinal transit time, bowel movements pe...
Le KM, Caston SS, Hossetter JM, Hay Kraus BL.To evaluate the analgesic and tissue effects of liposomal bupivacaine administered SC as an abaxial sesamoid nerve block in horses with experimentally induced lameness. Methods: 6 healthy mature light-breed horses. Methods: In a randomized crossover study, a circumferential hoof clamp was applied to a forelimb to induce reversible lameness. An abaxial sesamoid nerve block of the lame forelimb was performed by SC perineural injection of 10 mg of liposomal bupivacaine or bupivacaine HCl/site. Quantitative gait data were objectively obtained with a body-mounted inertial sensor system before (base...
Ferreira da Cruz FS, Natalini CC, Pellin de Molnar BF, Beatriz da Silva Serpa P, Tisotti T, Midon M, Desessards de La Côrte F.This study aimed to evaluate the effects and lameness degree in horses administered tramadol after the P-glycoprotein (P-gp) enteric inhibitor ivermectin. Six horses were randomly distributed into three groups, which received two different doses of tramadol by a nasogastric tube: 1 mg/kg (tramadol group 1(GT1)), 4 mg/kg (tramadol group 4 (GT4)), and tramadol 1 mg/kg combined with ivermectin 0.2 mg/kg PO (ivermectin tramadol group (GT1 + Ive)), with one-week washout interval. Heart rate (HR), respiratory rate (RR), intestinal motility, body temperature, and the degree of lameness were eval...
Fenner MF, Carstensen H, Dalgas Nissen S, Melis Hesselkilde E, Scott Lunddahl C, Adler Hess Jensen M, Loft-Andersen AV, Sattler SM, Platonov P....Inhibition of the G-protein gated ACh-activated inward rectifier potassium current, IK,ACh may be an effective atrial selective treatment strategy for atrial fibrillation (AF). Therefore, the anti-arrhythmic and electrophysiological properties of a novel putatively potent and highly specific IK,ACh inhibitor, XAF-1407 (3-methyl-1-[5-phenyl-4-[4-(2-pyrrolidin-1-ylethoxymethyl)-1-piperidyl]thieno[2,3-d]pyrimidin-6-yl]azetidin-3-ol), were characterised for the first time in vitro and investigated in horses with persistent AF. The pharmacological ion channel profile of XAF-1407 was investigated us...
Valle-Casuso JC, Gaudaire D, Martin-Faivre L, Madeline A, Dallemagne P, Pronost S, Munier-Lehmann H, Zientara S, Vidalain PO, Hans A.RNA viruses are responsible for a large variety of animal infections. Equine Arteritis Virus (EAV) is a positive single-stranded RNA virus member of the family Arteriviridae from the order Nidovirales like the Coronaviridae. EAV causes respiratory and reproductive diseases in equids. Although two vaccines are available, the vaccination coverage of the equine population is largely insufficient to prevent new EAV outbreaks around the world. In this study, we present a high-throughput in vitro assay suitable for testing candidate antiviral molecules on equine dermal cells infected by EAV. Using t...
Dau SL, Azevedo MDS, Mazaro RD, de La Corte FD, Fighera R.Neurolytic compounds are widely used by equine practitioners for the management of lameness, mostly related to the foot. The present study aimed to evaluate the neurotoxicity of 2% ammonium chloride (2% AC) applied adjacent to the palmar digital nerves in six miniature horses. The 2% AC and 0.9% saline solution were randomly injected into three and one palmar digital nerve of each horse, respectively. Nerve samples were collected by neurectomy performed under general anesthesia at 5, 12, 19, 35, 47, and 62 days after treatment, with one horse per day of surgery. The inflammatory reaction to p...
Albornoz A, Morales N, Uberti B, Henriquez C, Burgos RA, Alarcon P, Moran G.Neutrophils participate in innate immunity as the first line of host defence against microorganisms. However, persistent neutrophil activity and delayed apoptosis can be harmful to surrounding tissues; this problem occurs in diverse inflammatory diseases, including asthma-affected horses. Previous studies in horses with acute lung inflammation indicated that treatment with tamoxifen (TX), a selective oestrogen receptor modulator, produces a significant decrease in bronchoalveolar lavage fluid (BALF) neutrophil content. The aim of this study was to investigate the effect of tamoxifen and its me...
Rahnama S, Vathsangam N, Spence R, Anderson ST, de Laat MA, Bailey S, Sillence MN.Prolonged hyperinsulinemia is thought to be the cause of equine endocrinopathic laminitis, a common and crippling disease of the foot, for which there are no pharmacologic treatments other than pain relief. It has been suggested that insulin causes its effects on the lamellae by activating IGF-1 receptors (IGF-1R), as insulin receptors (InsR) are scarce in this tissue, whereas IGF-1R are abundant and become downregulated after prolonged insulin infusion. As a first step toward confirming this mechanism and beginning to develop a therapeutic anti-IGF-1R monoclonal antibody (mAb) for horses, it ...
Ortillés Á, Sanmartí J, Ríos J, Armengou L, Peña MT, Leiva M.To evaluate the effect of topical cyclopentolate hydrochloride (CH) on quantitative pupillometric readings (PR), tear production (TP), and intraocular pressure (IOP) in healthy horses. Methods: Fourteen client-owned horses. Methods: In a two-phase design study, each animal received 1% CH ophthalmic solution in the left eye [treated] and 0.9% NaCl in the right eye [control] (0.2 mL each). In the first phase (n = 7), TP, IOP, and PR assessment was performed by Schirmer tear test I, rebound tonometry and static pupillometry, at 1, 8, 24, 48, 72, 96, 120, 148, 172, and 196-hours post-instillati...
Kaps M, Okada CTC, Gautier C, Aurich J, Scarlet D, Kuhl J, Aurich C.Behavior during the estrous cycle of mares can affect their performance and therefore inhibition of cyclical ovarian activity is indicated. We hypothesized that implants containing the GnRH analog deslorelin downregulate GnRH receptors and inhibit ovulation in mares. The estrous cycles of Shetland mares were synchronized with 2 injections of a PGF analog. One day after the second injection (day 0), mares received 9.4 (group D1, n = 6) and 4.7 mg deslorelin (D2, n = 5) as slow-release implants or 1.25 mg short-acting deslorelin as a control (C, n = 5). Ultrasonography of the reproductive trac...
Bryant CE, Ouellette A, Lohmann K, Vandenplas M, Moore JN, Maskell DJ, Farnfield BA.Sepsis and endotoxaemia are important causes of morbidity and mortality in humans. Research on sepsis focuses on rodent models most of which are poorly responsive to lipopolysaccharide (LPS), and thus do not mimic very well the high sensitivity of humans. Therefore, there is a need to develop more clinically relevant models. Horses suffer from a similar endotoxaemic syndrome to humans with high morbidity and mortality. LPS analogues that act as antagonists at Toll-like receptor 4 (TLR4) are being developed as novel treatments for endotoxaemia. Due to differences in recognition of ligands by TL...
Steffey EP, Pascoe PJ, Woliner MJ, Berryman ER.To quantitate dose- and time-related anesthetic-sparing effects of xylazine hydrochloride (XYL) during isoflurane-induced anesthesia in horses and to characterize selected physiologic responses of anesthetized horses to administration of XYL. Methods: 6 healthy adult horses. Methods: Horses were anesthetized 2 times to determine the minimum alveolar concentration (MAC) of isoflurane in O2 and to characterize the anesthetic-sparing effect (MAC reduction) after IV administration of XYL (0.5 and 1 mg/kg of body weight, random order). Selected measures of cardiopulmonary function, blood glucose co...
Moore BR, Hinchcliff KW.Heparin is used clinically in horses to treat hemostatic abnormalities associated with severe gastrointestinal disease, septicemia, and endotoxemia. The primary anticoagulant effect of heparin is through the suppression of thrombin-dependent amplification of the coagulation cascade, and inhibition of thrombin-mediated conversion of fibrinogen to fibrin. Heparin may be of benefit in preventing the complications associated with hypercoagulable states such as jugular vein thrombosis, laminitis, and organ failure. Heparin may also be beneficial in the prevention of intraabdominal adhesions after g...
Driessen B, Nann L, Benton R, Boston R.To study whether hemodynamic function in horses, particularly mean arterial blood pressure (MAP), is better maintained with sevoflurane than isoflurane, thus requiring less pharmacological support. Methods: Prospective randomized clinical investigation. Animals Thirty-nine racehorses undergoing arthroscopy in lateral recumbency. Methods: Horses were assigned to receive either isoflurane (n = 20) or sevoflurane (n = 19) at 0.9-1.0 minimum alveolar concentration (MAC) for maintenance of anesthesia. Besides routine clinical monitoring, cardiac output (CO) was measured by lithium dilution. Hemodyn...
Zielinski K, Sekula B, Bujacz A, Szymczak I.Serum albumin, the most abundant transport protein of mammalian blood, interacts with various nonsteroidal anti-inflammatory drugs (NSAIDs) affecting their disposition, metabolism, and excretion. A big group of chiral NSAIDs transported by albumin, profens, is created by derivatives of 2-arylpropionic acid. The chiral center in the structures of profens is adjacent to the carboxylate moiety and often determines different pharmacological properties of profen enantiomers. This study describes crystal structures of two albumins, isolated from equine and leporine serum, in complexes with three pro...
Enderle AK, Levionnois OL, Kuhn M, Schatzmann U.To compare isoflurane alone or in combination with systemic ketamine and lidocaine for general anaesthesia in horses. Methods: Prospective, randomized, blinded clinical trial. Methods: Forty horses (ASA I-III) undergoing elective surgery. Methods: Horses were assigned to receive isoflurane anaesthesia alone (ISO) or with ketamine and lidocaine (LKI). After receiving romifidine, diazepam, and ketamine, the isoflurane end-tidal concentration was set at 1.3% and subsequently adjusted by the anaesthetist (unaware of treatments) to maintain a light plane of surgical anaesthesia. Animals in the LKI ...
Tarigo-Martinie JL, Wyatt AR, Kaplan RM.To determine the prevalence and clinical implications of anthelmintic resistance in cyathostomes of horses. Methods: Prospective study. Methods: 80 horses on 10 farms in a 5-county region of northeast Georgia. Methods: On each farm, horses were stratified in descending order according to pretreatment fecal egg count (FEC), blocked into groups of 4, and then randomly assigned to 1 of 4 treatment groups: no treatment (controls), and treatment with pyrantel pamoate, fenbendazole, or ivermectin. Fecal samples were collected 24 hours prior to treatment and 2, 4, and 6 weeks after treatment for dete...
Sweeney CR, Soma LR, Maxson AD, Thompson JE, Holcombe SJ, Spencer PA.The effects of furosemide on the racing times of 79 horses without exercise-induced pulmonary hemorrhage (EIPH) and 52 horses with EIPH were investigated. Racing times were adjusted to 1-mile equivalent racing times by 2 speed handicapping methods, and analysis of covariance was used to adjust actual racing times by winning time and distance for each race. All 3 methods of determining racing time indicated that geldings without EIPH had significantly faster racing times (P less than 0.05) when given furosemide before racing than when furosemide was not given before racing. Females and colts wi...
Williams DC, Aleman MR, Brosnan RJ, Fletcher DJ, Holliday TA, Tharp B, Kass PH, Steffey EP, LeCouteur RA.Previous study of the diagnostic validity of electroencephalography (EEG) to detect abnormalities in equine cerebral cortical function relied on the administration of various drugs for sedation, induction, and maintenance of general anesthesia but used identical criteria to interpret recordings. Objective: To determine the effects of 2 inhalation anesthetics on the EEG of healthy horses. Methods: Six healthy horses. Methods: Prospective study. After the sole administration of one of either isoflurane or halothane at 1.2, 1.4, and 1.6 times the minimum alveolar concentration, EEG was recorded d...
Jochle W, Moore JN, Brown J, Baker GJ, Lowe JE, Fubini S, Reeves MJ, Watkins JP, White NA.Detomidine hydrochloride, butorphanol tartrate, flunixin meglumine and xylazine hydrochloride were evaluated in a blind multi-centre clinical trial in 152 horses with abdominal pain. The drugs were administered as follows: detomidine 20 or 40 micrograms/kg bodyweight (bwt); butorphanol 0.1 mg/kg bwt; flunixin meglumine 1.0 mg/kg bwt; xylazine hydrochloride 0.5 mg/kg bwt. Each centre compared responses to the two doses of detomidine with those to one of the other analgesics. The drugs were administered intravenously (i.v.) after clinical assessment of the degree of sweating, kicking, pawing, he...
Trim CM, Hanson RR.The intravenous administration of xylazine (1.1 mg/kg bodyweight) in six ponies resulted in a significant increase in urine output over two hours, with maximum flow occurring between 30 and 60 minutes after injection. Urine specific gravity, osmolality and glucose concentration decreased. Renal clearance of endogenous creatinine was unchanged. Significant increases in the excretion of potassium and chloride occurred. Plasma glucose concentration was increased 30 minutes after the administration of xylazine by a mean value of 37 per cent. Serum osmolality and sodium, potassium and chloride conc...
Leclere M, Lefebvre-Lavoie J, Beauchamp G, Lavoie JP.Orally administered prednisolone and dexamethasone are used commonly in the treatment of recurrent airway obstruction (RAO) in horses. However, the efficacy of prednisolone in improving pulmonary function during continuous antigen exposure has not been evaluated critically and there is little evidence supporting the efficacy of low-dose oral dexamethasone in the same conditions. Objective: Oral prednisolone and dexamethasone improve pulmonary function in RAO under conditions of continuous antigen exposure, and dexamethasone is more effective than prednisolone at commonly used dosages. Methods:...
Gozalo-Marcilla M, Luna SP, Crosignani N, Filho JNP, Possebon FS, Pelligand L, Taylor PM.To evaluate intravenous (IV) detomidine with methadone in horses to identify a combination which provides sedation and antinociception without adverse effects. Methods: Randomized, placebo-controlled, blinded, crossover. Methods: A group of eight adult healthy horses aged (mean ± standard deviation) 7 ± 2 years and 372 ± 27 kg. Methods: A total of six treatments were administered IV: saline (SAL); detomidine (5 μg kg; DET); methadone (0.2 mg kg; MET) alone or combined with detomidine [2.5 (MLD), 5 (MMD) or 10 (MHD) μg kg]. Thermal, mechanical and electrical nociceptive thresholds were mea...
Welsh CE, Duz M, Parkin TDH, Marshall JF.Electronic medical records from first opinion equine veterinary practice may represent a unique resource for epidemiologic research. The appropriateness of this resource for risk factor analyses was explored as part of an investigation into clinical and pharmacologic risk factors for laminitis. Amalgamated medical records from seven UK practices were subjected to text mining to identify laminitis episodes, systemic or intra-synovial corticosteroid prescription, diseases known to affect laminitis risk and clinical signs or syndromes likely to lead to corticosteroid use. Cox proportional hazard ...
Frondoza CG, Fortuno LV, Grzanna MW, Ownby SL, Au AY, Rashmir-Raven AM.Objective Pro-inflammatory mediators such as prostaglandin E-2 (PGE2) play major roles in the pathogenesis of osteoarthritis (OA). Although current pharmacologic treatments reduce inflammation, their prolonged use is associated with deleterious side effects prompting the search for safer and effective alternative strategies. The present study evaluated whether chondrocyte production of PGE2 can be suppressed by the combination of avocado/soybean unsaponifiables (ASU) and α-lipoic acid (LA). Design Chondrocytes from articular cartilage of equine joints were incubated for 24 hours with: (1) con...
Picandet V, Léguillette R, Lavoie JP.Corticosteroids are currently the most effective drugs for the control of 'heaves' in horses. However, there is limited information concerning the comparative efficacy and tolerability of the various corticosteroids when used for treatment. Objective: To compare the therapeutic and side effects of isoflupredone acetate to those of dexamethasone. Methods: A parallel design to compare the effects of 2 corticosteroids by evaluating lung function, serum cortisol and electrolyte concentrations, response to ACTH stimulation and haematology sequentially during a 14 day control period (no treatment), ...
Du J, White N, Eddington ND.The purpose of this study was to determine if glucosamine (GL) hydrochloride (FCHG49) and low molecular weight (LMW) chondroitin sulfate (CS) (TRH122) are absorbed after oral administration to horses. The bioavailability of LMWCS was evaluated by quantifying the total disaccharides found in the plasma following chondroitinase ABC digestion. Methods: Two separate studies were conducted. In study 1, ten adult horses received the following four treatments in a randomized crossover fashion: (1) i.v. LMWCS (3 g of 8 kDa), (2) p.o. LMWCS (3 g of 8 kDa), (3) i.v. LMWCS (3 g of 16.9 kDa) and (4) p.o. ...
Nielsen MK, Sauermann CW, Leathwick DM.Anthelmintic resistance is widespread in equine cyathostomin populations across the world, and with no new anthelmintic drug classes in the pharmaceutical pipeline, the equine industry is forced to abandon traditional parasite control regimens. Current recommendations aim at reducing treatment intensity and identifying high strongylid egg shedders in a targeted treatment approach. But, virtually nothing is known about the effectiveness of these recommendations, nor their applicability to different climatic regions, making it challenging to tailor sustainable recommendations for equine parasite...
Atyabi N, Yasini SP, Jalali SM, Shaygan H.Nitrite intoxication occurs frequently in ruminants and equines. The most common treatment of this disorder is administration of 1% methylene blue, although the use of some antioxidant agents e.g. vitamins and complementary treatment may also be useful. The aim of this study was to evaluate the in vitro antioxidative effects of some vitamins on methemoglobinemia induced by sodium nitrite. For this purpose the blood sample of a healthy dairy cattle was pre-incubated with three different concentrations (5, 10, 20 mmol L(-1)) of each vitamin (E, C, B1, A and a combination of vitamin E and vitamin...
Greene SA, Thurmon JC, Tranquilli WJ, Benson GJ.Eight ponies were anesthetized with a solution containing 50 mg of guaifenesin, 1 mg of ketamine, and 0.5 mg of xylazine X ml-1 of 5% dextrose in water. Anesthesia was induced by IV injection (1.1 ml X kg-1), followed by continuous IV infusion at 2.75 ml X kg-1 X hr-1. Heart rate, rate-pressure product, mean pulmonary artery pressure, and standard bicarbonate were not significantly changed throughout the study. Systolic, diastolic, and mean arterial pressures and left ventricular stroke work index were significantly decreased at 5 and 15 minutes after a bolus of the anesthetic solution was inj...
D'Arcy-Moskwa E, Noble GK, Weston LA, Boston R, Raidal SL.Newer NSAIDs that more selectively target the induced isoform of the cyclooxygenase enzyme (COX2) activity might reduce adverse effects while preserving therapeutic benefits of these drugs. Objective: To compare the effect of oral administration of multiple dose rates of meloxicam and phenylbutazone (PBZ) on gastric mucosal integrity in horses. Methods: Twenty-five light breed horses. Methods: In vivo toxicity study. Horses were randomly assigned to 5 treatment groups, receiving placebo, PBZ (4.4 mg/kg PO q12h day 1, 2.2 mg/kg PO q12h for 4 days, 2.2 mg/kg PO q24h for 9 days), or 3 dose rates ...
Steffey EP, Mama KR, Galey FD, Puschner B, Woliner MJ.To quantitate effects of dose of sevoflurane and mode of ventilation on cardiovascular and respiratory function in horses and identify changes in serum biochemical values associated with sevoflurane anesthesia. Methods: 6 healthy adult horses. Methods: Horses were anesthetized twice: first, to determine the minimum alveolar concentration (MAC) of sevoflurane and second, to characterize cardiopulmonary and serum biochemical responses of horses to 1.0, 1.5, and 1.75 MAC multiples of sevoflurane during controlled and spontaneous ventilation. Results-Mean (+/- SEM) MAC of sevoflurane was 2.84 +/- ...
Maria WS, Cambuy MO, Costa JO, Velarde DT, Chávez-Olórtegui C.The correlation coefficients between in vivo neutralization of lethal toxicity (ED50), neutralization of the hemolytic activity (PLA2) and levels of antibodies measured by ELISA, was investigated to test the potency of horse anti-bothropic antivenom. Twenty six horses were hyperimmunized with Bothrops venoms (B. alternatus, B. jararaca, B. jararacussu, B. neuwiedii and B. moojeni). To set up an indirect ELISA, for neutralization of PLA2 activity and for determination of ED50 in Swiss mice, the whole Bothrops jararaca venom (reference venom for assessing the bothropic antivenom potency in Brazi...
Franck T, Kohnen S, Grulke S, Neven P, Goutman Y, Peters F, Pirotte B, Deby-Dupont G, Serteyn D.In the horse, the inflammation response to various pathologies (intestinal strangulations, laminitis, etc.) involves an excessive stimulation of the polymorphonuclear neutrophils releasing reactive oxygen species (ROS) and myeloperoxidase (MPO). The aim of the present work was to study the effect of natural polyphenols, curcuminoids and tetrahydrocurcuminoids (THC) on isolated stimulated equine neutrophils and on the activity of purified MPO. The ROS production and the release of MPO by activated neutrophils were measured by chemiluminescence and ELISA techniques, respectively. The activity of...
Hammond RA, Hannon R, Frean SP, Armstrong SJ, Flower RJ, Bryant CE.To determine the amount of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzymes induced in vitro in equine alveolar macrophages in response to lipopolysaccharide (LPS). Sample Population-Alveolar macrophages obtained from 12 horses. Methods: Alveolar macrophages were collected by bronchoalveolar lavage from 12 horses and incubated for 6 hours with LPS (0.001 to 10 microg/ml) or vehicle. Total RNA was extracted and purified. After first-strand cDNA synthesis, mRNA induction was measured, using a polymerase chain reaction (PCR) technique for COX-2, iNOS, and glyceraldehyde...
van Loon JP, Menke ES, L'ami JJ, Jonckheer-Sheehy VS, Back W, René van Weeren P.Epidural morphine is widely used in veterinary medicine, but there is no information about the anti-hyperalgesic and anti-inflammatory effects in acute inflammatory joint disease in horses. The analgesic, anti-hyperalgesic and anti-inflammatory effects of epidural morphine (100mg/animal or 0.17 ± 0.02 mg/kg) were therefore investigated in horses with acute synovitis. In a cross-over study, synovitis was induced in the talocrural joint by intra-articular lipopolysaccharide (LPS). The effect of epidural morphine was evaluated using physiological, kinematic and behavioural variables. Ranges of m...
Song Y, Day CM, Afinjuomo F, Tan JE, Page SW, Garg S.While the global market for veterinary products has been expanding rapidly, there is still a lack of specialist knowledge of equine pharmaceutics. In many cases, the basic structure of the gastrointestinal tract (GIT) and integumentary system of the horse shares similarities with those of humans. Generally, the dosage form developed for humans can be repurposed to deliver equine medications; however, due to physiological variation, the therapeutic outcomes can be unpredictable. This is an area that requires more research, as there is a clear deficiency in literature precedence on drug delivery...
Whitehair KJ, Steffey EP, Willits NH, Woliner MJ.To study behavioral and cardiopulmonary characteristics of horses recovering from inhalation anesthesia, 6 nonmedicated horses were anesthetized under laboratory conditions on 3 different days, with either halothane or isoflurane in O2. Anesthesia was maintained at constant dose (1.5 times the minimum alveolar concentration [MAC]) of halothane in O2 for 1 hour (H1), halothane in O2 for 3 hours (H3), or isoflurane in O2 for 3 hours (I3). The order of exposure was set up as a pair of Latin squares to account for horse and trial effects. Circulatory (arterial blood pressure and heart rate) and re...
Sun WC, Moore JN, Hurley DJ, Vandenplas ML, Linden J, Cao Z, Murray TF.Adenosine is an endogenous nucleoside that regulates many physiological processes by activating one or more adenosine receptor subtypes, namely A1, A2A, A2B and A3. The results of previous studies indicate that adenosine analogues inhibit lipopolysaccharide (LPS)-induced production of reactive oxygen species (ROS) by equine neutrophils primarily through activation of A2A receptors. Because peripheral blood monocytes produce cytokines that are responsible for many of the deleterious effects of LPS, the current study was performed to evaluate the effects of an array of novel adenosine receptor a...
Meyer GA, Lin HC, Hanson RR, Hayes TL.This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to admi...
