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.
Joyner RL, Liu CC, Cremer J, Carter RT, Lewin AC.Intravenous sedation is frequently necessary for ophthalmic examination in horses. Common sedation protocols have not been directly compared in terms of relative intraocular pressure (IOP) reduction, duration of IOP reduction and time to maximum IOP reduction. Objective: To compare the effects of standing sedation protocols on IOP. Methods: Randomised cross-over experiment. Methods: Twelve healthy horses received four intravenous sedation protocols with a 48 hours washout: 0.5 mg/kg xylazine and 0.01 mg/kg butorphanol (SED1); 10 µg/kg detomidine and 0.01 mg/kg of butorphanol (SED2); 10 ...
Alvarado TD, Mariezcurrena Berasain MD, Salem AZM, Pinzón Martínez DL.Functional biocompounds beneficial for animals and humans are in Mexican folk herbs. Cuphea and Eryngium species presented antimicrobial potential. Natural antibiotic uses by ethnoveterinary research with medicinal plants in equine infection or digestive diseases need more scientific evidence. Staphylococcus aureus, Escherichia coli, Salmonella enterica serotype Enteritidis are etiological agents in horses responsible for stable infections, abortions, fetal or perinatal deaths, and resistant intrahospital infections. The main objective of the present research was to evaluate the potential of a...
VanderBroek AR, Engiles JB, Kästner SBR, Kopp V, Verhaar N, Hopster K.Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia. Objective: To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse. Methods: Randomised, controlled, experimental study. Methods: Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum...
Hernández-Avilés C, Love CC, Serafini R, Ramírez-Agámez L, Kelley DE, de Andino EM, Teague SR, LaCaze KA, Brinsko SP, Varner DD.In this study, the effectiveness of supplementing INRA-96® extender (INRA-Control; original antibiotic formulation: potassium penicillin G = 38 μg/mL; gentamicin sulfate = 105 μg/mL; amphotericin B = 0.315 μg/mL) with amikacin sulfate and potassium penicillin G (AP) was determined. In Exp. 1, two sources of amikacin (INRA-AP-Sigma or INRA-AP-GoldBio) in combination with penicillin G were compared with ticarcillin/clavulanate (INRA-Tim) or no-supplemental antibiotics (INRA-Control) to examine effects on sperm quality and commensal bacterial growth. No differences were detected in s...
Thieulent C, Hue ES, Sutton G, Fortier C, Dallemagne P, Zientara S, Munier-Lehmann H, Hans A, Paillot R, Vidalain PO, Pronost S.Equid herpesvirus-1 infections cause respiratory, neurological and reproductive syndromes. Despite preventive treatments with vaccines, resurgence of EHV-1 infection still constitutes a major threat to equine industry. However, no antiviral compound is available to treat infected horses. In this study, 2891 compounds were screened against EHV-1 using impedance measurement. 22 compounds have been found to be effective in vitro against EHV-1. Valganciclovir, ganciclovir, decitabine, aphidicolin, idoxuridine and pritelivir (BAY 57-1293) are the most effective compounds identified, and their antiv...
De Ridder T, Ruppin M, Wheeless M, Williams S, Reddell P.Tigilanol tiglate is a novel small molecule approved as a veterinary pharmaceutical in Europe for intratumoural treatment of non-metastatic, non-resectable canine mast cell tumors. The drug has a "tumor agnostic" mode of action associated with induction of an acute inflammatory response at the treatment site, immune cell recruitment, and disruption of tumor vasculature. Consequently, tigilanol tiglate has potential in treating a range of tumor types in humans and companion animals. However, it is likely that species-specific dosing and concomitant medication protocols will be required, especia...
Alonso BB, La Rosa L, Carregaro AB, Gasthuys F, Schauvliege S.To examine the influence of detomidine or romifidine on recovery quality from isoflurane anesthesia, 78 anesthetic records were reviewed, from horses that had received romifidine (group R) during premedication [80-120 μg kg IV], anesthetic maintenance (40 μg kg hour IV), and recovery (20 μg kg IV) or detomidine (group D), at doses of 10-20 μg kg IV, 5 μg kg hour IV, and 2.5 μg kg IV, respectively. Duration of the different recovery phases, the number of attempts to sternal and standing, scores for transition to standing (TrSta), balance and coordination once standing (BC), and fina...
Sierra-Rodriguez T, Groover ES, Lascola KM, Mora-Pereira M, Lee YH, Duran SH, Ravis WR, Spangler E, Hathcock T, Wooldridge AA.Voriconazole (VRC) is a potential treatment for pneumomycosis in horses. The objectives of this study were to determine if the delivery of Vfend using a Flexineb nebulizer produced clinically significant [VRC] in lower airways. The hypothesis was that [VRC] after delivery by nebulization would be greater in the pulmonary epithelial lining fluid than plasma. A secondary objective was to determine [VRC] in upper airways through the collection of nasopharyngeal wash (NPW) samples. Voriconazole solution [Vfend-6.25 mg/mL, 100 (n = 2), 200 (n = 3), 500 (n = 1) mg] was nebulized once in 6 health...
Villar T, Pascoli AL, Chaulagain S, Fadl-Alla BA, Martins BC.Corneal neovascularization can result from many pathological processes affecting the ocular surface leading to disturbances and opacifications that reduce corneal clarity and may impact vision. In veterinary medicine, the use of topical corticosteroid is contraindicated in the presence of ulcerative keratitis, and there is sparse research regarding safe medical alternatives to inhibit corneal neovascularization in dogs to improve visual outcome. To investigate the pigment epithelium-derived factor (PEDF) concentration in equine amniotic membrane homogenate (EAMH) and its in-vitro vascular endo...
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...
Davis JL, Little D, Blikslager AT, Papich MG.Ussing chambers have been used to study the mucosal permeability of drugs in humans, rats and other species. This data can then be used to develop in vitro/in vivo correlations (IVIVC) for drugs based on the Biopharmaceutics Classification System (BCS). Due to the poor oral bioavailability of many drugs in the horse, this method may be useful for screening drugs before development to determine if they warrant further study. Cephalexin (CPX), marbofloxacin (MAR), metronidazole (MTZ) and fluconazole (FCZ) were chosen for this study based on the wide range of physicochemical properties and bioava...
Scott I, Bishop RM, Pomroy WE.There is growing concern that given the high frequency with which anthelmintics are being administered to many horses, anthelmintic resistance amongst equine helminth populations will be an increasing problem, rendering many of the currently available products unusable with little prospect of new products becoming available, at least in the near future. Worldwide, much reliance has been placed on the macrocyclic lactone (ML) group of anthelmintics, but resistance has been reported to these products as well as to the two other major anthelmintic classes used in this species, the benzimidazoles ...
Trailovic SM, Rajkovic M, Marjanovic DS, Neveu C, Charvet CL. sp. is the only ascarid parasitic nematode in equids and one of the most threatening infectious organisms in horses. Only a limited number of compounds are available for treatment of horse helminthiasis, and sp. worms have developed resistance to the three major anthelmintic families. In order to overcome the appearance of resistance, there is an urgent need for new therapeutic strategies. The active ingredients of herbal essential oils are potentially effective antiparasitic drugs. Carvacrol is one of the principal chemicals of essential oil from , , , , and herbs. However, the antiparasi...
Herd RP, Gabel AA.Studies on a Thoroughbred breeding farm in Ohio from 1982 to 1988 demonstrated the value of three anthelmintic pastes (ivermectin, oxibendazole, pyrantel pamoate) in controlling benzimidazole resistant cyathostomes (small strongyles) in adult horses. However, a comparison of drug efficacy in suppressing faecal egg counts for the full period between treatments showed a significant reduction in efficacy of all drugs in yearling horses compared with adults. Mean faecal egg counts of adult horses were generally kept below 100 eggs per gram (epg) of faeces when using oxibendazole or pyrantel pamoat...
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...
Lyons ET, Drudge JH, Tolliver SC.Experimentally induced infections of Parascaris equorum in worm-free pony foals required 14 to 17 days for migration of the larvae through the liver and lungs, and 79 to 110 days to become gametogenically functional. Treatment of experimentally infected or naturally exposed foals during the parenteral phase of development, using levamisole at 8 mg/kg, a mixture of levamisole at 8 mg/kg plus piperazine at 88 mg base equivalent/kg, or dl-tetramisole at 10 mg/kg, was quite efficacious in (1) reducing the number of P. equorum larvae recovered from the small intestines of the foals at necropsy, or ...
van der Woerdt A, Gilger BC, Wilkie DA, Strauch SM.Intraocular pressure (IOP) was measured, using applanation tonometry, in both eyes of 20 horses after topical application of 0.5% proparacaine to the cornea. Ultrasonic pachymetry was used to measure central, mid-peripheral, and peripheral corneal thickness (CT) in all 4 quadrants of both eyes of 25 horses. All measurements were repeated after auriculopalpebral nerve block, sedation by IV administration of xylazine, or combination of nerve block and sedation. Mean IOP after topical anesthesia of the cornea was 20.6 +/- 4.7 mm of Hg for the left eye and 20.35 +/- 3.7 mm of Hg for the right eye....
Rush BR, Raub ES, Thomsen MM, Davis EG, Matson CJ, Hakala JE.To evaluate clinical response, pulmonary function, and adrenal gland response to incremental doses of beclomethasone dipropionate in horses with recurrent airway obstruction. Methods: Crossover trial. Methods: 8 horses with recurrent airway obstruction. Methods: Horses randomly assigned to 4 groups were treated twice daily via aerosol administration of placebo or 500, 1,000, or 1,500 micrograms of beclomethasone dipropionate in a crossover design with a 10-day minimum washout period. Subjective assessment of airway obstruction, serum cortisol concentration, and maximum change in pleural pressu...
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...
Martens RJ, Mealey K, Cohen ND, Harrington JR, Chaffin MK, Taylor RJ, Bernstein LR.To determine the pharmacokinetics of gallium maltolate (GaM) after intragastric administration in healthy foals. Methods: 6 healthy neonatal foals. Methods: Each foal received GaM (20 mg/kg) by intragastric administration. Blood samples were obtained before (time 0) and at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, and 48 hours after GaM administration for determination of serum gallium concentrations by use of inductively coupled plasma mass spectroscopy. Results: Mean +/- SD pharmacokinetic variables were as follows: peak serum gallium concentration, 1,079 +/- 311 ng/mL; time to peak serum concentra...
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...
