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.
Hopster K, Ambrisko TD, Stahl J, Schramel JP, Kästner SB.Previous studies showed an influence of xylazine on the LiDCO sensor in vitro and in standing horses, but did not prove that this interaction caused error in LiDCO measurements. Therefore, agreement of cardiac output (CO) measurements by LiDCO and bolus-thermodilution (BTD) was determined in horses receiving xylazine infusions. Methods: Prospective, experimental study. Methods: Eight Warmblood horses. Methods: All horses were premedicated with xylazine. Anaesthesia was induced with midazolam and ketamine and was maintained with isoflurane in oxygen. During six hours of anaesthesia CO measureme...
Sykes BW, Sykes KM, Hallowell GD.A previous study demonstrated that a dose effect between 1.6 and 4.0 mg/kg bwt of omeprazole per os s.i.d. is present in the treatment of equine gastric ulceration. In the same study, healing of glandular ulceration appeared inferior to healing of squamous ulceration. However, several limitations were recognised in that study and further investigation is warranted. Objective: To further investigate the presence of a dose relationship in the treatment of gastric ulceration under conditions that may favour omeprazole efficacy such as administration prior to exercise and after a brief fast, and...
Ho EN, Kwok WH, Leung DK, Riggs CM, Sidlow G, Stewart BD, Wong AS, Wan TS.Testosterone is an endogenous steroid produced primarily in the testes. Trace levels of testosterone are found in urine samples from geldings, as testosterone is also secreted by the adrenal. An international threshold of free and conjugated testosterone in urine (20 ng/mL) was adopted by the International Federation of Horseracing Authorities (IFHA) in 1996 for controlling testosterone misuse in geldings. In view of the recent popularity of using blood in doping control testing, it is necessary to establish a threshold for testosterone in gelding plasma. A liquid chromatography-mass spectro...
Lizarraga I, Castillo-Alcala F.Combinations of α2 -adrenoceptor and opioid agonists are commonly used in equids, but little scientific information is available on donkeys. Objective: To compare the sedative and hypoalgesic effects of xylazine alone or in combination with different dosages of butorphanol in donkeys. Methods: Placebo-controlled, operator-blinded, randomised, crossover, Latin square study. Methods: Six donkeys received intravenous normal saline and normal saline (NS-NS); xylazine (0.5 mg/kg bwt) and normal saline (X-NS); xylazine and 10 μg/kg bwt butorphanol (X-B10); xylazine and 20 μg/kg bwt butorpha...
Betancourt A, Lyons ET, Horohov DW.Anthelmintic treatments have been associated with local inflammatory reactions. Since each class of anthelmintic has unique mechanisms of action affecting different subpopulations of parasites, we hypothesised that they will also induce characteristic proinflammatory responses. Objective: To determine the effect of anthelmintic class on the proinflammatory response post treatment. Methods: Ponies naturally infected with cyathostomins and other parasites after pasture grazing were left untreated or treated with representatives of 3 different classes of anthelmintics: fenbendazole (benzimidazole...
Hart KA, Sherlock CE, Davern AJ, Lewis TH, Robertson TP.N-butylscopolammonium bromide (NBB) is an anticholinergic agent used to treat spasmodic colic in horses. Intestinal smooth muscle spasm also occurs in horses with intraluminal intestinal obstructions, such as ileal impactions. The antispasmodic effects of NBB may be useful in managing ileal impactions, but the effects of NBB on equine ileal smooth muscle are unknown. Objective: To investigate the effects of NBB on spontaneous and induced contraction of the equine ileum in an ex vivo model. Methods: Ex vivo biomechanical study assessing contractile properties in isolate equine ileal smooth musc...
Marzok MA, El-Khodery SA, Oheida AH.To evaluate the effect of intravenous administration of romifidine on the intraocular pressure (IOP) in horses. Methods: Twenty-four horses with no ocular abnormalities. Methods: Horses were randomly assigned into two equal groups (treatment and control). All horses in the treatment group received an intravenous (IV) injection of romifidine (40 μg/kg). The horses in the control group were administrated an intravenous injection of 0.9% saline (0.4 mL/100 kg). In both groups, the IOP values were measured immediately (T0 ) pre-administration and at 5 (T5 ), 15 (T15 ), 30 (T30 ), 45 (T45 ), 60 (T...
Tappenbeck K, Hoppe S, Geburek F, Feige K, Huber K.By blocking the enteric nervous system (ENS) using tetrodotoxin (TTX), previous studies have documented the contractility-enhancing (CE) effects of lidocaine in equine intestinal smooth muscle (SM) at the level of SM cells and/or interstitial cells of Cajal (ICC). The present study examined the impact of ENS deactivation on CE lidocaine effects, and investigated the effects of lidocaine on ENS activity. TTX application did not affect the CE effects of lidocaine, indicating that these were not mediated by TTX-sensitive sodium channels. Application of TTX or ≥100 mg/L lidocaine reduced ENS a...
Norman TE, Batista M, Lawhon SD, Zhang S, Kuskie KR, Swinford AK, Bernstein LR, Cohen ND.This study's objective was to determine the in vitro antimicrobial activities of gallium maltolate (GaM) and 20 other antimicrobial agents against clinical equine isolates of Corynebacterium pseudotuberculosis. The growth of cultured isolates was not inhibited by any concentration of GaM. MIC data revealed susceptibility to commonly used antimicrobials.
Harlow BE, Lawrence LM, Kagan IA, Flythe MD.The goals of this study were to determine if β-acid from hops (Humulus lupulus L.) could be used to control fructan fermentation by equine hindgut micro-organisms, and to verify the antimicrobial mode of action on Streptococcus bovis, which has been implicated in fructan fermentation, hindgut acidosis and pasture-associated laminitis (PAL) in the horse. Results: Suspensions of uncultivated equine faecal micro-organisms produced fermentation acids when inulin (model fructan) was the substrate, but β-acid (i.e. lupulone) concentrations ≥9 ppm inhibited lactate production and mitigated the d...
Pinto NI, Gilger BC.To determine the feasibility of using a handheld spectral-domain optical coherence tomography (SD-OCT) instrument to characterize normal corneal, retinal, and optic nerve head anatomy in vivo in standing horses. Methods: Clinically normal horses under sedation, palpebral nerve blockage, and pharmacologically induced mydriasis were imaged with a SD-OCT instrument (Envisu SD-OCT, Bioptigen, Inc., Morrisville, NC). Radial volumes from the cornea (axial, superior, inferior, nasal, and temporal), and rectangular volumes from the retina (dorsal, ventral, nasal, and temporal) and optic nerve head wer...
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. These drugs include lidocaine, ketamine, opioids and α2 -agonists. The Part 1 of this review will focus in the use of lidocaine and ketamine. Methods: Pubmed & Web of Science. Search terms: horse, inhalant anaesthesia, balanced anaesthesia, partial intravenous anaesthesia, lidocaine, ketamine. Conclusions: Different drugs and their combinations can be administered systemically in anaesthetized horses, with the aim of reducing the amount of the volatile agen...
Underwood C, Collins SN, van Eps AW, Allavena RE, Medina-Torres CE, Pollitt CC.There are no experimentally validated pharmacological means of preventing laminitis; however, locally acting pharmaceutical agents with the potential to prevent laminitis have been identified. Demonstrating therapeutic drug concentrations in lamellar tissue is essential for evaluating the efficacy of these agents. The aim of this study was to develop an experimental technique for repeatedly sampling lamellar interstitial fluid. A technique for placing ultrafiltration probes was developed in vitro using 15 cadaver limbs. Subsequently, lamellar ultrafiltration probes were placed in one forelimb ...
Stine JM, Michau TM, Williams MK, Kuebelbeck KL, Stengard ME.Original study. Objective: To evaluate the effect of sedation with romifidine hydrochloride 1% (Sedivet: Boehringer-Ingelheim) on intraocular pressure (IOP) in the normal horse and horses with incidental ophthalmic findings as measured by applanation tonometry. Methods: Nineteen clinically normal horses (13 geldings, six mares) and eight horses (three geldings, five mares) with incidental ophthalmic findings were included in this study. Methods: All horses underwent complete ophthalmic examination with pharmacologic mydriasis a minimum of 2 weeks prior to IOP evaluation. Baseline intraocular p...
Sheats MK, Pescosolido KC, Hefner EM, Sung EJ, Adler KB, Jones SL.Neutrophil infiltration is a prominent feature in a number of pathologic conditions affecting horses including recurrent airway obstruction, ischemia-reperfusion injury, and laminitis. Cell signaling components involved in neutrophil migration represent targets for novel anti-inflammatory therapies. In order to migrate into tissue, neutrophils must respond to chemoattractant signals in their external environment through activation of adhesion receptors (i.e. integrins) and reorganization of the actin cytoskeleton. Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS), a highly conserved actin...
Balssa F, Fischer M, Bonnaire Y.5(10)-Estrene-3β,17α-diol is an essential reference material for doping analysis in horse-racing laboratories. It is used to detect misuse, for doping purpose, of the pregnancy status in the mare. Its stereoselective synthesis from 17β-estradiol-3-methyl ether (prepared from estrone or 17β-estradiol) was performed in four steps: (1) Mitsunobu inversion of the 17β-alcohol; (2) Birch reduction of the aromatic ring; (3) stereoselective reduction of the 3-ketone via Noyori asymmetric transfer hydrogenation; (4) chemoenzymatic purification.
Bujacz A, Zielinski K, Sekula B.Serum albumin, a protein naturally abundant in blood plasma, shows remarkable ligand binding properties of numerous endogenous and exogenous compounds. Most of serum albumin binding sites are able to interact with more than one class of ligands. Determining the protein-ligand interactions among mammalian serum albumins is essential for understanding the complexity of this transporter. We present three crystal structures of serum albumins in complexes with naproxen (NPS): bovine (BSA-NPS), equine (ESA-NPS), and leporine (LSA-NPS) determined to 2.58 Å (C2), 2.42 Å (P61), and 2.73 Å (P2₁2₁...
Geurden T, van Doorn D, Claerebout E, Kooyman F, De Keersmaecker S, Vercruysse J, Besognet B, Vanimisetti B, di Regalbono AF, Beraldo P, Di Cesare A....The objective of the present study was to evaluate the efficacy of an oral treatment with ivermectin (IVM) or moxidectin (MOX) against gastro-intestinal strongyles in naturally infected horses by performing a faecal egg count reduction test (FECRT) and by monitoring the egg reappearance period (ERP) after treatment. Therefore, a field efficacy study with a randomised complete block design for each study site was conducted, with the individual animal as the experimental unit. At least 10 study sites in Italy, Belgium and The Netherlands were selected and animals were allocated to one of the two...
Mangal D, Uboh CE, Soma LR, Liu Y.Glucocorticoids (corticosteroids) are widely used anti-inflammatory agents in veterinary medical practice. These drugs are considered doping agents because they mask pain and thus, increase injury potential in equine athletes. They exhibit anti-inflammatory property by binding to glucocorticoids receptor (GR) to control the transcription of pro- and anti-inflammatory cytokines and enzymes involved in the synthesis of bioactive eicosanoids. To evaluate the role of triamcinolone acetonide (TA) on concentrations of bioactive eicosanoids in equine plasma, TA (0.04 mg/kg) was intravenously administ...
Wohlfender FD, Doherr MG, Driessen B, Hartnack S, Johnston GM, Bettschart-Wolfensberger R.Multicentre Confidential Enquiries into Perioperative Equine Fatalities (CEPEF) have not been conducted since the initial CEPEF Phases 1-3, 20 years ago. Objective: To collect data on current practice in equine anaesthesia and to recruit participants for CEPEF-4. Methods: Online questionnaire survey. Methods: An online questionnaire was prepared and the link distributed internationally to veterinarians possibly performing equine anaesthesia, using emails, posters, flyers and an editorial. The questionnaire included 52 closed, semiclosed and open questions divided into 8 subgroups: demographic ...
Agrawal K, Ebel JG, Bischoff K.Most antidoping method development in the equine industry has been for plasma and urine, though there has been recent interest in the analysis of synovial fluid for evidence of doping by intra-articular corticosteroid injection. Published methods for corticosteroid analysis in synovial fluid are primarily singleplex methods, do not screen for all corticosteroids of interest and are not adequately sensitive. The purpose of this study is to develop a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) screening method for the detection of four of the most common intra-a...
Kullmann A, Sanz M, Fosgate GT, Saulez MN, Page PC, Rioja E.Alpha-2 agonist-induced changes in packed cell volume (PCV), total solids (TS), selected biochemical parameters, and splenic thickness were investigated in horses. Four healthy mares were treated in a blinded, randomized, cross-over design with a dose of xylazine (0.5 mg/kg), romifidine (0.04 mg/kg), or detomidine (0.01 mg/kg) IV, and detomidine (0.02 mg/kg) IM. Hematology, TS, colloid osmotic pressure (COP), plasma osmolality; glucose, lactate, urea (BUN) and electrolyte concentrations; venous blood pH and ultrasonographic splenic thickness were evaluated at intervals for 300 min. Repeated me...
Aarnes TK, Bednarski RM, Bertone AL, Hubbell JA, Lerche P.The objective of this study was to compare recovery from desflurane anesthesia in horses with or without post-anesthetic xylazine. Six adult horses were anesthetized on 2 occasions, 14 d apart using a prospective, randomized crossover design. Horses were sedated with xylazine, induced to lateral recumbency with ketamine and diazepam, and anesthesia was maintained with desflurane. One of 2 treatments was administered intravenously at the end of anesthesia: xylazine [0.2 mg/kg body weight (BW)] or an equivalent volume of saline. Recovery parameters were recorded and assessed by 2 blinded observe...
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 ...
Tappenbeck K, Schmidt S, Feige K, Naim HY, Huber K.Lidocaine is the most commonly chosen prokinetic for treating postoperative ileus in horses, a motility disorder associated with ischaemia-reperfusion injury of intestinal tissues. Despite the frequent use of lidocaine, the mechanism underlying its prokinetic effects is still unclear. Previous studies suggested that lidocaine altered cell membrane characteristics of smooth muscle cells. Therefore, the present study aimed to elucidate effects of lidocaine administration on characteristics of detergent-resistant membranes in equine jejunal smooth muscle. Lidocaine administration caused significa...
Brennan KM, Urschel KL.Dexamethasone is an anti-inflammatory drug commonly used in equine medicine. Insulin sensitivity decreases with prolonged dexamethasone administration, but little information is available about the duration of this side effect after long-term treatment ends. Objective: To determine how long it takes for blood glucose, insulin and markers of insulin sensitivity to return to normal ranges after extended dexamethasone treatment has ceased. Methods: Experimental study. Methods: Eight healthy, mature, mixed-breed horses received 0.04 mg/kg bwt/day oral dexamethasone for 21 days. Blood samples wer...
Fenton JI, Chlebek-Brown KA, Caron JP, Orth MW.Glucosamine inhibits recombinant human interleukin-1 stimulated cartilage degradation in equine cartilage explants. Recently, recombinant equine interleukin-1 has been cloned and purified. Therefore, the objective of this study was to characterise the effects of glucosamine on indices of cartilage degradation in recombinant equine IL-1beta-stimulated equine articular cartilage explants. Cartilage discs were harvested from the weight-bearing region of the articular surface of the antebrachiocarpal and middle carpal joints of horses (age 2-8 years) and cultured under standard conditions. Explant...
Frean SP, Lees P.To investigate effects of the anti-arthritic agents hyaluronan and polysulfated glycosaminoglycan (PSGAG) on inflammatory metabolism in cultured equine synoviocytes. Methods: Synoviocytes cultured from samples obtained from the metacarpophalangeal joints of 4 horses. Methods: Equine synoviocytes were grown in monolayer culture. Synoviocytes were stimulated with lipopolysaccharide (LPS) and simultaneously treated with various concentrations of hyaluronan or PSGAG for 48 hours. Three hyaluronan preparations were compared. Prostaglandin E2 (PGE2) concentrations in culture medium were measured, us...
Yamanaka T, Oku K, Koyama H, Mizuno Y.To clarify time-related changes in equine cardiovascular system during maintenance anesthesia (180 min, 1.2 minimum alveolar concentration) with sevoflurane (Sev-group) compared to isoflurane (Iso-group) as the basis for clinical use of Sev, horses were examined for the heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), systemic vascular resistance (SVR) and pre-ejection period (PEP)/ejection time (ET) that is an index of the cardiac contractility. The HR was almost 30 beats/min in both groups without significant temporal change. MAP was significantly elevated with time but the...
Gray PR, Derksen FJ, Robinson NE, Carpenter-Deyo LJ, Johnson HG, Roth RA.Airway obstruction and hyperreactivity are characteristics of human asthma and of "heaves," a naturally occurring respiratory disorder of horses and ponies. To document the role of cyclooxygenase products of arachidonic acid metabolism in the pathogenesis of heaves, we measured plasma and bronchoalveolar lavage (BAL) fluid concentrations of metabolites of thromboxane (TX)A2 and prostaglandins (PG) I2 and D2 in five affected ponies and their age- and gender-matched controls prior to and during acute airway obstruction precipitated by housing the ponies in a barn and exposing them to hay dust. P...
Nielsen MK, Donoghue EM, Stephens ML, Stowe CJ, Donecker JM, Fenger CK.Parascaris spp. infections can lead to life-threatening small intestinal impactions in foals. Currently available diagnostic techniques cannot estimate the magnitude of an ascarid burden, and hence identify foals potentially at risk of developing impactions. Objective: To describe and evaluate an ultrasonographic transabdominal scoring technique for monitoring of ascarid burdens in foals and to perform a cost-benefit analysis of the application of this technique. Methods: A transabdominal ultrasonographic technique was validated against ascarid worm counts from 10 foals aged 162-294 days. In a...
Anderson MJ, Ibrahim AS, Cooper BR, Woolcock AD, Moore GE, Taylor SD.Sepsis is associated with ascorbic acid (AA) depletion and critical illness-related corticosteroid insufficiency (CIRCI) in humans. Objective: Intravenous infusion of lipopolysaccharide (LPS) would (a) decrease endogneous AA concentrations, (b) induce CIRCI and (c) administration of a combination of AA and hydrocortisone (HC) would have decreased indices of inflammation compared to either drug alone. Methods: Thirty-two healthy horses. Methods: Randomized placebo-controlled experimental trial. Horses were assigned to 1 of 4 groups (saline, AA and HC, AA only, or HC only). Treatments were admin...
Jiménez BLM, Elghandour MMMY, Adegbeye MJ, Tirado González DN, Tirado Estrada G, Salem AZM, Pacheco EBF, Pliego AB.In the race against deadly diseases, multiple drugs have been developed as a treatment strategy in livestock. Each treatment is based on a specific mechanism to find a suitable drug. Antibiotics have become a fundamental part of the equine industry to treat bacterial diseases. These antibiotics have specific doses and side effects, and understanding each parameter allows veterinarians to avoid or limit the adverse effects of such drugs. Use of antibiotics causes microbial imbalance, decreased microbial diversity and richness in both cecal and fecal samples. Antibiotics reduced metabolites prod...
Rush BR, Worster AA, Flaminio MJ, Matson CJ, Hakala JE.To determine alteration in adrenocortical function in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure to moldy hay and straw for 7 days (natural challenge). Horses then underwent treatment (aerosolized beclomethasone, parenterally administered dexamethasone, and aerosolized propellant) for 7 days. Horses remained in the mold-contaminated environment for 7 days after discontinuat...
Théon AP, Pascoe JR, Galuppo LD, Fisher PE, Griffey SM, Madigan JE.To determine the benefits of reducing the interval between surgical cytoreduction and intratumoral administration of cisplatin. Methods: Randomized clinical study. Methods: 70 horses with 89 incompletely resected T2- and T3-stage sarcoids (n = 64) and squamous cell carcinomas (25). Methods: Horses were given 4 intratumoral treatments of cisplatin at 2-week intervals. The first treatment was given at the time of, or immediately after, surgical resection for horses treated in accordance with the perioperative protocol (group 1). Horses in group 2 were treated with cisplatin after the skin healed...
Wagner AE, Mama KR, Steffey EP, Hellyer PW.To determine whether infusion of xylazine (XYL) and ketamine (KET) for 30 minutes after isoflurane administration in horses would result in improved quality of recovery from anesthesia, without detrimental cardiopulmonary changes. Methods: Randomized, blinded experimental trial. Methods: Seven healthy adult horses aged 6.4 +/- 1.9 years and weighing 506 +/- 30 kg. Methods: Horses were anesthetized twice, at least 1 week apart. On both occasions, anesthesia was induced by the administration of XYL, diazepam, and KET, and maintained with isoflurane for approximately 90 minutes, the last 60 minut...
Manohar M, Hutchens E, Coney E.Catheter mounted micro-tip-manometers (the signals from which were matched with fluid-filled pressure signals from same cardiovascular sites and zeroed at the point of the shoulder), were used to study pulmonary haemodynamics in 8 healthy sound horses at rest and during exercise performed at 8, 10, 12 and 14 m/s on a treadmill. Measurements were made without frusemide (control) and 4 h after iv administration of 250 mg frusemide. Post-frusemide data were also obtained on a separate day, and these observations were not significantly different from those made on the same day as controls. Pre-fru...
Morris LH, Colgan S, Leathwick DM, Nielsen MK.Parasite control in foals is complicated by the concurrent presence of biologically diverse parasites with differing levels of anthelmintic resistance. Several combination anthelmintic products are available for use in horses, but information on their efficacies against important equine parasites is scarce. Two trials were performed in New Zealand during 2008 and 2011 on four different farms with substantially different anthelmintic treatment histories. The first trial evaluated the efficacy of an ivermectin/praziquantel/oxibendazole combination, a single active oxibendazole, and a single-acti...
Elliott J, Berhane Y, Bailey SR.To determine in vitro vasoactive potency of monoamines formed in the cecum and found in the systemic circulation of horses. Methods: Segments of digital blood vessels obtained from 6 healthy mixed-breed horses and ponies euthanatized at an abattoir and platelets isolated from 4 healthy ponies. Methods: Paired rings of digital artery and vein from the same horse were examined, and isometric tension was recorded. Concentration-response curves for tryptamine (TRP), tyramine (TYR), phenylethylamine (PEA), isoamylamine (IAA), and isobutylamine (IBA) were obtained. Vasoconstrictor mechanisms were in...
Smith MA, Nolan TJ, Rieger R, Aceto H, Levine DG, Nolen-Walston R, Smith BI.In the last decade there have been numerous reports of anthelmintic resistant cyathostomins in many parts of the world. The objective of the present study was to evaluate the efficacy of the commercially available anthelmintics against cyathostomin egg shedding in the Mid-Atlantic region of the United States. A total of 989 horses from 67 different farms located in southeastern Pennsylvania, northern Delaware, and northeastern Maryland were treated with fenbendazole, oxibendazole, pyrantel pamoate, ivermectin, or moxidectin at their recommended dosages. Fecal egg count reduction testing was us...
Young JM, Schoonover MJ, Kembel SL, Taylor JD, Bauck AG, Gilliam LL.To evaluate the analgesic effects of orally administered gabapentin on horses with chronic thoracic limb lameness. Methods: Randomized, crossover design. Methods: A total of 14 adult horses with chronic thoracic limb lameness. Methods: Following baseline measurement of lameness, horses were administered each of four treatments orally in grain: treatment G, gabapentin (20 mg kg) twice daily for 13 doses; treatment F, firocoxib (171 mg once, then 57 mg once daily for six doses); treatment GF, gabapentin and firocoxib at previously stated doses and frequencies; or treatment C, grain only as a con...
Wellcome open researchNovember 5, 2018
Volume 3 58 doi: 10.12688/wellcomeopenres.14587.2
Loan HT, Yen LM, Kestelyn E, Hao NV, Thanh TT, Dung NTP, Turner HC, Geskus RB, Wolbers M, Tan LV, Van Doorn HR, Day NP, Wyncoll D, Hien TT....Despite long-standing availability of an effective vaccine, tetanus remains a significant problem in many countries. Outcome depends on access to mechanical ventilation and intensive care facilities and in settings where these are limited, mortality remains high. Administration of tetanus antitoxin by the intramuscular route is recommended treatment for tetanus, but as the tetanus toxin acts within the central nervous system, it has been suggested that intrathecal administration of antitoxin may be beneficial. Previous studies have indicated benefit, but with the exception of one small trial n...
Dabernat HJ, Delmas CF, Tainturier DJ, Lareng MB.The in vitro susceptibility of recent clinical isolates of Haemophilus equigenitalis to various antimicrobial agents was determined by the disk diffusion test and the World Health Organization-International Collaborative Study agar dilution procedure. Ampicillin and tetracycline were the most active drugs. All strains were susceptible to beta-lactam antibiotics, chloramphenicol, trimethoprim-sulfamethoxazole, nalidixic acid, nitrofurantoin (Furadantin), and bacitracin. All but two strains were resistant to streptomycin, whereas all strains were susceptible to the other aminocyclitol antibodies...
Young SS, Tesarowski D, Viel L.The effect of measurement frequency on respiratory mechanics was investigated in six horses with reversible allergic airway disease. Total respiratory impedance was measured at 1.5, 2.0, 3.0, and 5.0 Hz by using the forced oscillation technique with the horses in remission, after acute antigenic challenge producing clinical heaves, and with heaves but after the administration of 2 mg fenoterol by inhalation. The slopes of the magnitude (magnitude of Zrs) and real part (R) of total respiratory impedance over the frequency range 1.5-3 Hz changed significantly after antigenic challenge and fenote...
Baxter GM.Low doses of endotoxin cause vasoconstriction and hypoperfusion of the digit, small intestine, and cecum in horses. To determine the potential cause of these vascular alterations, in vitro vascular responses of palmar digital arteries and veins were determined in 8 horses after intravenous (IV) infusion of 1 L 0.9% NaCl (control) and 0.1 microgram/kg Escherichia coli 055:B5 endotoxin in 1 L of 0.9% NaCl (endotoxin-treated). Vessels were surgically removed under general anesthesia, cut into 4-mm vascular rings, suspended in tissue baths, and attached to force displacement transducers for measur...
Hu HH, MacAllister CG, Payton ME, Erkert RS.To compare analgesic effects of phenylbutazone administered at a dosage of 4.4 mg/kg/d (2 mg/lb/d) or 8.8 mg/kg/d (4 mg/lb/d) in horses with chronic lameness. Methods: Controlled crossover study. Animals-9 horses with chronic forelimb lameness. Methods: Horses were treated i.v. with phenylbutazone (4.4 mg/kg/d or 8.8 mg/kg/d) or saline (0.9% NaCl) solution once daily for 4 days. All horses received all 3 treatments with a minimum of 14 days between treatments. Mean peak vertical force (mPVF) was measured and clinical lameness scores were assigned before initiation of each treatment and 6, 12, ...
Gozalo-Marcilla M, Hopster K, Gasthuys F, Hatz L, Krajewski AE, Schauvliege S.Dexmedetomidine has been administered in the equine as a constant-rate infusion (CRI) during inhalation anaesthesia, preserving optimal cardiopulmonary function with calm and coordinated recoveries. Inhalant anaesthetic sparing effects have been demonstrated in other species, but not in horses. Objective: To determine the effects of a CRI of dexmedetomidine on the minimal alveolar concentration (MAC) of sevoflurane in ponies. Methods: Six healthy adult ponies were involved in this prospective, randomised, crossover, blinded, experimental study. Each pony was anaesthetised twice (3 weeks washou...
Holm-Martin M, Levot GW, Dawson KL.A gel formulation containing moxidectin (20 g/kg) and praziquantel (125 g/kg) reduced the geometric mean faecal strongyle egg count in horses to below 100 eggs per gram of faeces (epg) for at least 12 weeks despite their being exposed continuously to reinfection from pasture grazed by treated and untreated horses. The geometric mean egg count of horses treated with a proprietary paste containing abamectin (3.7 g/kg) and praziquantel (46.2 g/kg) increased steadily from six weeks after the treatment, peaking at over 820 epg after 12 weeks. Relative to the efficacy of the abamectin/praziquantel t...
Casella S, Giannetto C, Giudice E, Marafioti S, Fazio F, Assenza A, Piccione G.Adenosine diphosphate (ADP)-induced platelet aggregation in fed and fasted horses after addition of tramadol hydrochloride was evaluated in vitro. On 10 horses citrated blood samples were collected 2h after feeding (fed animals) and 21 h after feeding (fasted animals). Final concentrations of ADP 1 and 0.5 μM, and tramadol hydrochloride (1, 15, 30, 45 and 60 min after the addition of tramadol) were used to determine the maximum degree and initial velocity of platelet aggregation. Repeated measures multifactor analysis of variance (MANOVA) was used to evaluate the effect of feeding/fasting con...
Spadavecchia C, Arendt-Nielsen L, Spadavecchia L, Mosing M, Auer U, van den Hoven R.To assess the effects of a single intravenous dose of butorphanol (0.1 mg kg(-1)) on the nociceptive withdrawal reflex (NWR) using threshold, suprathreshold and repeated subthreshold electrical stimuli in conscious horses. Methods: 'Unblinded', prospective experimental study. Methods: Ten adult horses, five geldings and five mares, mean body mass 517 kg (range 487-569 kg). Methods: The NWR was elicited using single transcutaneous electrical stimulation of the palmar digital nerve. Repeated stimulations were applied to evoke temporal summation. Surface electromyography was performed to record a...
Cuniberti B, Odore R, Barbero R, Cagnardi P, Badino P, Girardi C, Re G.Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenases (COX), and the inhibition of COX-2 rather than COX-1 can limit the onset of NSAID-related adverse effects. The pharmacodynamic properties of eltenac, naproxen, tepoxalin, SC-560 and NS 398 in healthy horses were investigated using an in vitro whole blood assay. To predict COX selectivity in clinical use, eltenac and naproxen were also studied ex vivo after intravenous administration. SC-560 acted as a selective COX-1 inhibitor, tepoxalin as a dual inhibitor with potent activity against COX-1, and NS 398 as a preferential CO...
Gough MR, Mayhew G, Munroe GA.This paper tests the hypothesis that the local analgesic agent mepivacaine diffuses between adjacent equine synovial structures in the forelimb and with greater frequency than latex, gelatine dye or contrast media. We report the incidence of diffusion of mepivacaine between the distal interphalangeal joint (DIPJ) and navicular bursa (NB) of the forelimbs and between the intercarpal (IC) and radiocarpal (RC) joints of 31 fresh equine cadavers. The DIPJ of one forelimb and the NB of the contra lateral forelimb and the RC joint of one forelimb and the IC joint of the contra lateral forelimb were ...
Tiley HA, Geor RJ, McCutcheon LJ.To determine the effects of dexamethasone treatment on selected components of insulin signaling and glucose metabolism in skeletal muscle obtained from horses before and after administration of a euglycemic-hyperinsulinemic clamp (EHC). Methods: 6 adult Standardbreds. Methods: In a balanced crossover study, horses received either dexamethasone (0.08 mg/kg, IV, q 48 h) or an equivalent volume of saline (0.9% NaCl) solution, IV, for 21 days. A 2-hour EHC was administered for measurement of insulin sensitivity 1 day after treatment. Muscle biopsy specimens obtained before and after the EHC were a...
Giguère S, Slade JK, Sanchez LC.Despite a lack of data regarding their efficacy, both caffeine and doxapram have been recommended for treatment of hypercapnia in equine neonates with central nervous system damage. Objective: Caffeine and doxapram alleviate hypercapnia in foals with hypoxic-ischemic encephalopathy. Methods: Sixteen foals treated with either caffeine (n = 8) or doxapram (n = 8). Methods: Information on age, body temperature, heart rate, respiratory rate, arterial blood gas parameters, duration of therapy, and outcome was abstracted from each medical record. Results: Therapy with doxapram resulted in a signific...
Witonsky S, Buechner-Maxwell V, Santonastasto A, Pleasant R, Werre S, Wagner B, Ellison S, Lindsay D.Equine protozoal myeloencephalitis (EPM) is a common and devastating neurologic disease of horses in the United States. Because some EPM-affected horses have decreased immune responses, immunomodulators such as levamisole have been proposed as supplemental treatments. However, little is known about levamisole's effects or its mechanism of action in horses. Objective: Levamisole in combination with another mitogen will stimulate a macrophage 1 (M1), dendritic cell 1 (DC1), T-helper 1 (CD4 Th1), and T-cytotoxic (CD8) immune response in equine peripheral blood mononuclear cells (PBMCs) in vitro a...
Nannarone S, Spadavecchia C.To compare the ability of 2 partial IV anesthesia (PIVA) techniques to maintain anesthesia, compared with isoflurane alone, in horses. Methods: 45 horses. Methods: Client-owned horses requiring general anesthesia for a variety of procedures of at least 1 hour's duration were randomly allocated to 3 groups (n = 15/group) that differed for the maintenance protocol. Anesthesia was maintained with isoflurane with a starting end-tidal isoflurane concentration of 1.3% (isoflurane group) or a concentration of 1% supplemented with an adjustable continuous infusion of guaifenesin-ketamine (IGK group) o...
