The topic of drugs and horses encompasses the study of various pharmacological agents used in equine medicine for therapeutic purposes. This includes the administration of medications for pain management, disease treatment, and performance enhancement. The pharmacokinetics and pharmacodynamics of drugs in horses are key areas of research, as they determine the absorption, distribution, metabolism, and excretion of these substances. Additionally, the topic covers the detection and regulation of substances in competitive equestrian sports to ensure fair play and animal welfare. This page compiles peer-reviewed research studies and scholarly articles that explore the effects, safety, and regulatory aspects of drug use in equine health and performance.
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...
Schwarz B, Ihry P.A 26-year-old pony mare (ca. 180 kg bodyweight) was presented as an emergency because it had erroneously received 110 times its standard dose of pergolide (Prascend) per os approximately 4 hours earlier. Clinical examination initially was normal except tachycardia of 52 beats/min. The pony was treated symptomatically with paraffin oil and activated charcoal per nasogastric tube to prevent further systemic absorption and accelerate intestinal excretion of the pergolide. Furthermore, the pony received 400 mg of dopamine antagonist azaperone (Stresnil) intramuscularly (i.m.) followed by 80 mg...
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...
Jinks MR, Miller EJ, Diaz-Campos D, Mollenkopf DF, Newbold G, Gemensky-Metzler A, Chandler HL.To identify the minimum inhibitory concentration (MIC) distribution for commonly used topical antibiotics from isolates of dogs and horses with ulcerative bacterial keratitis, and to investigate changes in MIC values over time and following treatment with topical fluoroquinolones. Methods: One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis. Methods: Minimum inhibitory concentration values for 14 topical antibiotics were reported for canine and equine cases of bacterial ulcerative keratitis between 2013 and 2018. Changes in MIC values over t...
Göktaş EF, Kabil E, Arıöz F.Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in therapeutic doses in human and veterinary medicine for the treatment of inflammation, pain, and fever. A method for the simultaneous determination of nine NSAIDs, known as therapeutic prohibited substances, in equine urine was developed and fully validated according to the European Commission Decision 2002/657/EC and Association of Official Racing Chemists criteria. The validation was performed for naproxen, flunixin, ketoprofen, diclofenac, eltenac, meclofenamic acid, phenylbutazone, vedaprofen, and carprofen in equine urine i...
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...
Studzińska MB, Sallé G, Roczeń-Karczmarz M, Szczepaniak K, Demkowska-Kutrzepa M, Tomczuk K.Parascaris spp. are major gastro-intestinal nematodes that infect foals and can lead to respiratory symptoms, poor growth, and in some cases obstruction of the small intestine and death. Ivermectin resistance has been reported for Parascaris spp. in many countries. In Poland, the knowledge of the level of resistance against ivermectin in Parascaris spp. is limited. The aim of this study was to examine the efficacy of ivermectin against Parascaris spp. in foals from south-eastern Poland. Foals (n = 225 = reared in 7 stud farms) were treated orally with ivermectin paste. Faecal samples w...
Karasek I, Butler C, Baynes R, Werners A.Ectoparasites infestations are a growing concern to horse owners and equine veterinarians alike. Ectoparasites cause significant health and welfare issues and can potentially can serve as vectors for a variety of pathogens. The prevalence of ectoparasites increases around the world, and especially in horses information on the successful prevention and treatment of ectoparasite infestations in scarce and in many instances anecdotal. This poses a challenge to the equine veterinarian and off-label use of drugs can lead to detrimental effects in horses. In this review we describe the current avail...
Waraksa E, Owczarek K, Kubica P, Kłodzińska E, Ozimek M, Wrzesień R, Bobrowska-Korczak B, Namieśnik J.Bromhexine (BH), expectorant used in the treatment of respiratory disorders associated with viscid or excessive mucus, is not permitted for use in the competing horse by many authorities in horseracing and Olympic disciplines. Metabolic studies are of the great importance in anti-doping field because they allow for updating the selection of the most appropriate markers for prohibited substances, such as metabolites present at higher concentration levels and/or lasted for a longer period of time in biological samples than a parent drug. This study describes LC-MS/MS-based method for simultaneou...
de Grauw J, van Loon T.To compare the effects of two different doses of butorphanol combined with detomidine administered intravenously (IV) on quality of sedation, degree of ataxia and anaesthetic induction in horses. Methods: Randomized, blinded, clinical study. Methods: A total of 40 client-owned healthy warmblood horses scheduled for elective surgery under general anaesthesia. Methods: Horses were randomly allocated to be administered 8 μg kg-1 detomidine IV plus either 20 or 50 μg kg-1 butorphanol IV, with the principal investigator blinded to group allocation. Head height was measured before drug injection a...
Gadaj A, Ventura E, Healy J, Botrè F, Sterk SS, Buckley T, Mooney MH.Selective androgen receptor modulators (SARMs) represent non-steroidal agents commonly abused in human and animal (i.e. equine, canine) sports, with potential for further misuse as growth promoting agents in livestock-based farming. As a direct response to the real and possible implications of illicit application in both sport as well as food production systems, this study incorporated enzymatic hydrolysis (β-glucuronidase/arylsulfatase) into a previously established protocol while maintaining the minimal volume (200 µL) of urine sample required to detect SARMs encompassing various pharmacop...
Shibany KA, Pratt SL, Aldurdunji M, Totemeyer S, Paine SW.Horses are exposed to various kinds of medication, however, there are limited determinations of plasma clearance (CL) for the drugs used due to the high cost of equine studies.Many of the CL values generated come from the equine sports industry for determining drug plasma screening limits in the control of medications at the time of competition.The kinetics of omeprazole metabolism were investigated in freshly isolated and cryopreserved equine hepatocytes and hepatic microsomes ( = 3 horses).The V, K and intrinsic clearance (CL) of omeprazole were determined via the substrate depletion me...
Hopster K, Soma LR, Li X, Hopster-Iversen C, Boston RC, Driessen B.Intravenous (i.v.) bolus administration of xylazine (XYL) (0.5 mg/kg) immediately followed by a continuous rate infusion (CRI) of 1 mg kg hr for 2, 4, and 6 hr produced immediate sedation, which lasted throughout the duration of the CRI. Heart rate decreased and blood pressure increased significantly (p > .05) in all horses during the first 15 min of infusion, both returned to and then remained at baseline during the duration of the infusion. Compartmental models were used to investigate the pharmacokinetics of XYL administration. Plasma concentration-time curves following bolus an...
Wong JKY, Chan GHM, Choi TLS, Kwok KY, Lau MY, Leung GNW, Wan TSM, Ho ENM.A high-throughput method has been developed for the doping control analysis of 124 drug targets, processing up to 154 horse urine samples in as short as 4.5 h, from the time the samples arrive at the laboratory to the reporting deadline of 30 min before the first race, including sample receipt and registration, preparation and instrument analysis and data vetting time. Sample preparation involves a brief enzyme hydrolysis step (30 min) to detect both free and glucuronide-conjugated drug targets. This is followed by extraction using solid-supported liquid extraction (SLE) and analysis using liq...
Mizobe F, Mori M, Nagata SI, Yamashita S, Okada J, Kusano K.Ever since 'One Health' concept was introduced in early 2000s, judicious use of antimicrobials by veterinarians has become an issue of great concern. Recently, findings of anti-inflammatory effects in certain types of antimicrobials have raised a subject for discussion among racing authorities. Regulatory framework of antimicrobials in racing should be based on best interest of horse welfare and doping control perspective, but basic data on prevalence of antimicrobials are lacking. Analysis of 100 postrace urinary samples collected from 10 Japanese racecourses by targeting 21 antimicrobials us...
Tamura N, Okano A, Kuroda T, Niwa H, Kusano K, Matsuda Y, Fukuda K, Mita H, Nagata S.To clarify the detailed pharmacokinetics (PK) of orally administered voriconazole in tear fluid (TF) of horses for evaluating the efficacy of voriconazole secreted into TF against equine keratomycosis. Methods: Five healthy Thoroughbred horses. Methods: Voriconazole was administrated through a nasogastric tube to each horse at a single dose of 4.0 mg/kg. TF and blood samples were collected before and periodically throughout the 24 hours after administration. Voriconazole concentrations in plasma and TF samples were analyzed using liquid chromatography-electrospray tandem-mass spectrometry. T...
Wong ASY, Choi TLS, Kwok KY, Wong JKY, Wan TSM, Ho ENM.Antipsychotics are banned substances and considered by the Fédération Equestrian Internationale (FEI) to have no legitimate use in equine medicine and/or have a high potential for abuse. These substances are also prohibited in horseracing according to Article 6 of the International Agreement on Breeding, Racing and Wagering (published by the International Federation of Horseracing Authorities). Over the years, antipsychotics have been abused or misused in equestrian sports and horseracing. A recent review of literature shows that there is yet a comprehensive screening method for antipsychoti...
McCracken MJ, Schumacher J, Doherty TJ, Sun X, Nichols CL, Olivarez J.To determine the efficacy and duration of effect for liposomal bupivacaine following perineural administration to the medial and lateral palmar digital nerves of horses. Methods: 9 nonlame mares. Methods: For each horse, 2 mL of liposomal bupivacaine (13.3 mg/mL; total dose, 53.2 mg or approx 0.11 mg/kg) or sterile saline (0.9% NaCl) solution was injected adjacent to the medial and lateral palmar digital nerves at the level of the distal aspect of the proximal sesamoid bones of a randomly selected forelimb. Twenty-one days later, the opposite treatment was administered in the contralateral for...
Schnepf A, Bienert-Zeit A, Ertugrul H, Wagels R, Werner N, Hartmann M, Feige K, Kreienbrock L.The usage of antimicrobial drugs (AMs) leads to an increase in antimicrobial resistance (AMR). Although different antimicrobial usage (AMU) monitoring programs exist for livestock animals in Germany, there is no such system for horses. However, with the increasing usage of electronic practice management software (EPMS), it is possible to analyze electronic field data generated for routine purposes. The aim of this study was to generate AMU data for German horses with data from the Clinic for Horses (CfH), University of Veterinary Medicine Hannover (TiHo), and in addition to show that different...
Skelding AM, Valverde A.Sympathomimetic drugs mimic the physiological action of the sympathetic nervous system through interaction with adrenergic receptors. These drugs are commonly used to provide cardiovascular support in many veterinary species. Despite their common use, the literature evaluating their effectiveness can be somewhat limited depending on the species. This review details the mechanism of action of various sympathomimetic drugs and summarizes the literature that is available describing the efficacy of these drugs and their use in anesthetized veterinary species.
Recchi L, Alvariza S, Benech A, Ruiz N, José Estradé M, Suarez G, Crosignani N.The purpose of this study was to evaluate the pharmacokinetics of oral amitriptyline in horses. Oral amitriptyline (1 mg/kg) was administered to six horses. Blood samples were collected from jugular and lateral thoracic vein at predetermined times from 0 to 24 hr after administration. Plasma concentrations were determined by high-performance liquid chromatography and analyzed using noncompartmental methods. Pharmacodynamic parameters including heart rate, respiration rate, and intestinal motility were evaluated, and electrocardiographic examinations were performed in all subjects. The mean m...
Meier M, Bettschart-Wolfensberger R, Schwarzwald CC, Portier K, Gysler A, Ringer SK.Dobutamine is routinely used to improve cardiovascular function in anaesthetized horses. However, dobutamine in conscious horses is insufficiently investigated. Ten research horses that were already instrumented for a preceding trial were included into the study. Cardiovascular variables were recorded and blood samples taken after instrumentation (Baseline), before starting dobutamine and after 10 min of dobutamine infusion (2 µg kg min ). A significant increase in systemic blood pressure, mean pulmonary artery pressure and right atrial pressure, and a decrease in heart rate were observe...
Cox S, Sommardahl C, Fortner C, Davis R, Bergman J, Doherty T.Non-steroidal anti-inflammatory drugs are inhibitors of cyclooxygenase (COX) in tissues and used as therapeutic agents in different species. Grapiprant, a member of the piprant class of compounds, antagonizes prostaglandin receptors. It is a highly selective EP4 prostaglandin E receptor inhibitor, thereby limiting the potential for adverse effects caused by wider COX inhibition. The objectives of this study were to determine if the approved canine dose would result in measurable concentrations in horses, and to validate a chromatographic method of analysis for grapiprant in urine and plasma. M...
Emmerich IU.In 2019, one novel pharmaceutical agent for horses or food-producing animals was released on the German market: An injection suspension for horses containing chondrogenic-induced equine allogeneic peripheral blood-derived mesenchymal stem cells as the active ingredient (ArtiCell Forte) is now available. Two established veterinary active pharmaceutical ingredients became accessible for additional species: a salicylanilide anthelmintic oxyclozanide (Distocur) for the treatment and control of fascioliasis in sheep as well as a type-I synthetic pyrethroid permethrin (Z-Itch), which now has additio...
Sampaio BFB, DeRossi R, Vieira N, Milan B, Ávila LG.The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330-370 kg and aged 10-15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 μg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 μg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidur...
Furr M, Kennedy T.Ponazuril is used for the treatment of equine protozoal myeloencephalitis (EPM). Coadministration of ponazuril with oil could result in higher serum and cerebrospinal fluid (CSF) concentrations of ponazuril. Objective: Coadministration of corn oil will result in higher serum and CSF concentrations of ponazuril than when ponazuril is administered alone. Methods: Ten resident university-owned adult horses of either sex and >2 years of age. Methods: Cohort study. Ponazuril oral paste (5 mg/kg BW; ponazuril treatment group (PON); n = 5), or ponazuril oral paste (5 mg/kg BW; ponazuril and oil tre...
Mora-Pereira M, Abarca EM, Duran S, Ravis W, McMullen RJ, Fischer BM, Lee YP, Wooldridge AA.Keratomycosis is a relatively common, sight threatening condition in horses, where treatment is often prolonged and costly. Subconjunctival (SCo) injections offer less resistance to drug diffusion than the topical route, resulting in better penetration to the ocular anterior segment. Voriconazole, a second generation triazole antifungal, is effective against common fungal organisms causing keratomycosis. If combined with a thermogel biomaterial, voriconazole can be easily injected in the SCo space to provide sustained drug release. The purpose of this study was to evaluate the drug concentrati...
Bauer C, Merkt JC, Janke-Grimm G, Bürger HJ.The prevalence of benzimidazole-resistant small strongyles was determined in a survey, conducted on 14 thoroughbred studs, which compared the faecal egg counts of groups of horses before and after treatment with the recommended doses of cambendazole (20 mg kg-1 b.w.) or febantel (6 mg kg-1 b.w.). Benzimidazole-resistant cyathostomes were found on all farms examined. Pyrantel pamoate (19 mg kg-1 b.w.), oxibendazole (10 mg kg-1 b.w.) and ivermectin (0.2 mg kg-1 b.w.) reduced the strongyle egg counts on these studs by 97-100% at 2 weeks post-treatment. However, 6 weeks after dosing the reduction ...
Barton MH, Paske E, Norton N, King D, Giguère S, Budsberg S.Two firocoxib preparations for oral use are approved for use in animals in many countries: a chewable canine tablet and an equine paste. In order to reduce costs, many veterinarians use the canine product in horses even though this is an off-label use of the preparation. Objective: To determine the relative efficacy of 2 commercially available firocoxib products to inhibit prostaglandin E₂ (PGE2) synthesis after oral dosing in horses. Methods: A crossover design using 8 adult horses (n = 4 for each preparation during each treatment period). Body weight range 532-614 kg. Methods: Horses recei...
Salim B, Bakheit MA, Sugimoto C.The application of high-resolution melting (HRM) analysis in the differentiation between Theileria equi and Babesia caballi was evaluated using control samples from the United States Department of Agriculture and field samples collected from horses in Sudan and China. A region of the 18S rRNA gene, with four known nucleotide differences between the two parasites, was selected for primer design. HRM analysis successfully allowed the detection and differentiation of T. equi and B. caballi without the necessity of performing time-consuming and expensive post-PCR procedures such as sequencing or r...
Geor RJ, Petrie L, Papich MG, Rousseaux C.The effects of sucralfate and ranitidine on the gastrointestinal manifestations of phenylbutazone (PBZ) toxicity in horse foals were determined by complete blood count, serum chemistry profile, and gross and histological necropsy examinations. Twenty-eight, three to four month old Belgian-cross foals were randomly assigned to one of four groups. Phenylbutazone was administered at a dosage of 10 mg/kg of bodyweight (BW) per day, intravenously (IV), in equally divided doses to three of the groups. In addition to PBZ, ranitidine was administered at 2 mg/kg BW, IV, twice daily, to one group of sev...
Ducharme NG, Fubini SL.Atropine sulfate was given at 2 dosages (0.044 mg/kg, 0.176 mg/kg) to clinically normal ponies in order to evaluate the drug's effect on the gastrointestinal tract. Intestinal motility, as assessed by ausculation of borborygmus, was stopped 30 minutes after injection, but it gradually returned to normal within 12 hours. Signs of abdominal pain developed in 3 of 10 ponies. In 3 clinical cases of gastrointestinal disorder, prior atropine treatment was confusing to the diagnostician and resulted in delayed surgical treatment in 1 case. It was concluded that atropine should not be used for allevia...
Vergara-Hernandez FB, Nielsen BD, Colbath AC.Osteoclasts are unique and vital bone cells involved in bone turnover. These cells are active throughout the individual's life and play an intricate role in growth and remodeling. However, extra-label bisphosphonate use may impair osteoclast function, which could result in skeletal microdamage and impaired healing without commonly associated pain, affecting bone remodeling, fracture healing, and growth. These effects could be heightened when administered to growing and exercising animals. Bisphosphonates (BPs) are unevenly distributed in the skeleton; blood supply and bone turnover rate determ...
Suagee JK, Corl BA, Wearn JG, Crisman MV, Hulver MW, Geor RJ, McCutcheon LJ.Obesity and insulin resistance increase the risk of laminitis in horses. Pioglitazone (PG) is an insulin-sensitizing drug used in humans that is absorbed after oral administration to horses. Objective: PG treatment will increase insulin sensitivity and transcript abundance of glucose and lipid transporters in adipose and skeletal muscle tissues. Methods: Sixteen lean, healthy horses. Methods: Eight horses were administered PG (1 mg/kg bodyweight PO) for 12 days before induction of insulin resistance through IV administration of lipopolysaccharide (LPS). Treated and untreated controls (CN; n = ...
Yiğin A.The extensive use of antibacterial agents used for treatment in human and veterinary clinics to increase yield in livestock and aquaculture in developing countries causes the detection and spread of multidrug-resistant (MDR) strains in different sources. The presence of Escherichia coli strains is very common in racehorses and it's a serious problem on horse farms. Extended-spectrum beta-lactamase (ESBL) production is an important source of MDR development in Gram-negative strains such as E.coli. This study aimed to detect the presence of ESBL genes in E. coli strains isolated from horse farms...
Lyons E.Population-S small strongyles have been studied since 1974 in central Kentucky in a closed Shetland pony breeding herd. The ponies were treated approximately every 8 weeks with cambendazole (1974-1978), oxibendazole (OBZ) (1978-1992), or pyrantel pamoate (PRT) (1992-1999). Small strongyles in the ponies have shown resistance to these compounds in field and critical tests. One purpose of this presentation was to compare different parameters for determination of effects on the small strongyle species in ponies after treatment, mainly with OBZ or PRT, from data in critical tests (n=112). Also, th...
Dahan R, Oreff GL, Tatz AJ, Raz T, Britzi M, Kelmer G.The objectives of this study were to evaluate the compatibility and the pharmacokinetic properties of combined amikacin and penicillin administration by intravenous regional limb perfusion (IVRLP) in horses. A tourniquet was applied proximal to the carpus of 7 clinically healthy adult horses and 2 g of amikacin and 10 × 10 IU of penicillin (100 mL total volume) were sequentially injected into the cephalic vein just distal to the tourniquet. Synovial samples were collected from the joint at several times after injection. All samples were analyzed for amikacin and penicillin concentration. The ...
Kamerling SG, Weckman TJ, DeQuick DJ, Tobin T.Pain perception and its alteration by analgesic drugs is difficult to measure in the horse. The latency to onset of flexion of a limb in response to a noxious thermal stimulus has been used as a nociceptive end point for analgesic studies in many species. While this method has been employed in the horse, it may be confounded by the spontaneous locomotor activity observed after administration of narcotic analgesics. Consequently, an alternative method of assaying narcotic analgesia that did not involve the equine locomotor apparatus was developed. This report describes the use of the heat-evoke...
Schauvliege S, Gasthuys F.Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often needed in anesthetized horses. Antimuscarinics can be used to treat bradycardia unrelated to hypertension. Vasopressors can be useful when hypotension is caused by vasodilation and/or when the effect of fluids and inotropes is insufficient. In most cases, however, inotropes, including sympathomimetics, calcium salts, and phosphodiesterase inhibitors, are preferred. Of the β-sympathomimetics, dobutamine remains the agent of choice. Calcium salts are mainly useful in hypocalcemic patients. Phosphodiest...
Errico JA, Trumble TN, Bueno AC, Davis JL, Brown MP.To compare isolated limb retrograde venous injection (ILRVI) and isolated limb infusion (ILI) for delivery of amikacin to the synovial fluid of the distal interphalangeal and metacarpophalangeal joints and to evaluate the efficacy of use of an Esmarch tourniquet in standing horses. Methods: 6 healthy adult horses. Methods: Horses were randomly assigned in a crossover design. In ILRVI, the injection consisted of 1 g of amikacin diluted to a total volume of 60 mL administered during a 3-minute period. In ILI, the infusion consisted of 1 g of amikacin diluted to 40 mL administered during a 3-minu...
Parry BW, Anderson GA.The effect of acepromazine maleate (ACP) on the equine venous haematocrit and total plasma protein concentration was studied in six clinically normal horses. Total plasma protein concentration was not appreciably influenced by ACP. However, the haematocrit decreased with the duration, but not the degree, of the decrease being dose-related. Mean haematocrit values returned to control levels by 12 h after 0.05 mg ACP/kg body weight and 21 h after 0.15 mg ACP/kg body weight.
Toutain PL.In racing and other equine sports, it is possible to increase artificially both the physical capability and the presence of a competitive instinct, using drugs, such as anabolic steroids and agents stimulating the central nervous system. The word doping describes this illegitimate use of drugs and the primary motivation of an equine anti-doping policy is to prevent the use of these substances. However, an anti-doping policy must not impede the use of legitimate veterinary medications and most regulatory bodies in the world now distinguish the control of illicit substances (doping control) from...
Gaustad G, Larsen S.A randomised double blind and placebo controlled clinical study was carried out. Standardbred trotters (n=77), age 3-4 years) with moderate to severe lameness were grouped according to number of affected joints and, within each group, were randomised for treatment with polysulphated glycosaminoglycan (PSGAG), sodium hyaluronate (SH) or placebo for 3 weeks. The horses were inspected weekly with a final examination 2-4 weeks after the end of treatment. Mean initial lameness score was significantly reduced during treatment and at the last examination in all 3 groups (P<0.01). Additionally, the...
Toro M, León E, López R, Pallota F, Garcia JA, Ruíz A.Assays dealing with the therapeutic and prophylactic activity of isometamidium on experimental infections by Trypanosoma vivax and T. evansi were carried out. The drug was found to be highly effective against T. vivax infection in sheep and cattle in which periods of protection ranging from 118 to 195 days were achieved. No complete effects against infection by T. evansi were observed. The drug was well tolerated in sheep and cattle while side-effects were noted in treated mares. It was concluded that isometamidium could be used to prevent damage and economical losses caused by T. vivax in Ven...
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.
Spyridaki MH, Lyris E, Georgoulakis I, Kouretas D, Konstantinidou M, Georgakopoulos CG.Xylazine and its main metabolites were detected in equine urine after a single-dose intravenous administration of 0.98 and 1.01 mg/kg body weight xylazine, respectively, in two horses, in order to be used for equine doping control routine analysis. The urine levels of the parent drug and its metabolites were determined using gas chromatography-mass spectrometry (GC-MS). Xylazine is metabolised rapidly, down to a concentration level of about 1.0 microg/ml after 1-3h administration. Seven metabolites were identified in urine. 4-Hydroxy-xylazine, the major metabolite, could be traced for 25 h and...
Larsen J.This review article describes the different aetiological agents known or suspected to cause colitis in the adult horse, namely Salmonella spp., Clostridium spp., Ehrlichia risticii, Cyathostomes, fungi, various antibiotics, drugs, and toxins, with emphasis on their mechanism of action. For each of the infectious agents, diagnostic procedures are indicated. The effects of endotoxin can be important in all forms of equine colitis.
Gilger BC, Stoppini R, Wilkie DA, Clode AB, Pinto NH, Hempstead J, Gerding J, Salmon JH.To describe the use of episcleral silicone matrix cyclosporine (ESMC) drug delivery devices in horses with immune-mediated keratitis (IMMK) with evaluation of tolerability and efficacy in long-term control of inflammation. Methods: Retrospective study. ESMC implants (1.2 cm length, 30% wt/wt cyclosporine (CsA) in silicone; with approximately 2 μg/day steady-state release for at least 400 days) were used. Results: Nineteen horses (20 eyes) received two or more ESMC implants for superficial stromal (n = 9), midstromal (n = 3), or endothelial (n = 5) IMMK. Three additional horses received two or...
Daunt DA, Steffey EP.Administration of alpha-2 agonists to horses produces a variety of behavioral effects (sedation, somnolence, analgesia), and physiological effects. One of the most significant beneficial effects of administering alpha-2 agonists is the degree of analgesia they provide. Alpha-2 agonists have been the mainstay of analgesia for colic pain in horses since their introduction to clinical veterinary medicine. The increased potency of the more recently introduced alpha-2 agonists allows the provision of analgesia for conditions not previously relieved by other drugs. Unfortunately, there are significa...
López-Sanromán FJ, Holmbak-Petersen R, Varela M, del Alamo AM, Santiago I.To evaluate the duration of effects on movement patterns of horses after sedation with equipotent doses of xylazine hydrochloride, detomidine hydrochloride, or romifidine hydrochloride and determine whether accelerometry can be used to quantify differences among drug treatments. Methods: 6 healthy horses. Methods: Each horse was injected IV with saline (0.9% NaCl) solution (10 mL), xylazine diluted in saline solution (0.5 mg/kg), detomidine diluted in saline solution (0.01 mg/kg), or romifidine diluted in saline solution (0.04 mg/kg) in random order. A triaxial accelerometric device was used f...
Larenza MP, Peterbauer C, Landoni MF, Levionnois OL, Schatzmann U, Spadavecchia C, Thormann W.To evaluate pharmacokinetics of ketamine and norketamine enantiomers after constant rate infusion (CRI) of a subanesthetic dose of racemic ketamine or S-ketamine in ponies. Methods: Five 6-year-old Shetland pony geldings that weighed between 101 and 152 kg. Methods: In a crossover study, each pony received a CRI of racemic ketamine (loading dose, 0.6 mg/kg; CRI, 0.02 mg/kg/min) and S-ketamine (loading dose, 0.3 mg/kg; CRI, 0.01 mg/kg/min), with a 1-month interval between treatments. Arterial blood samples were collected before and at 5, 15, 30, 45, and 60 minutes during drug administration and...
Duesterdieck-Zellmer KF, Driscoll N, Ott JF.To determine concentration-dependent effects of tiludronate on cartilage explants incubated with or without recombinant equine interleukin-1β (rEq IL-1). Methods: Articular cartilage explants from the femorotibial joints of 3 young adult horses. Methods: Cartilage explants were incubated with 1 of 6 concentrations (0, 0.19, 1.9, 19, 190, or 1,900 mg/L) of tiludronate and with or without rEq IL-1 (0.01 ng/mL) for 96 hours. Prostaglandin E(2) (PGE(2)) concentrations in culture medium and explant digests were analyzed via PGE(2) enzyme immunoassay. Sulfated glycosaminoglycan (sGAG) concentration...
Mancebo OA, Verdi JH, Bulman GM.On the basis of positive skin snips for Onchocerca cervicalis microfilariae (MF), 45 horses were chosen from 48 in a total of 257 screened on 12 locations in the northeast Province of Formosa (Argentina), and randomly assigned to two treatment groups of 20 horses each, and a nontreated control group of five horses. On Day 14 post-treatment (PT), skin snip samples in the ivermectin-treated (0.2 mg/kg) group were negative for normal viable microfilariae (MF), while horses in the control group maintained their pretreatment level of infection. On the same Day in the moxidectin-treated (0.4 mg/kg) ...
Scarth JP, Spencer HA, Timbers SE, Hudson SC, Hillyer LL.The detection of drug abuse in horseracing often requires knowledge of drug metabolism, especially if urine is the matrix of choice. In this study, equine liver/lung microsomes/S9 tissue fractions were used to study the phase I metabolism of eight drugs of relevance to equine drug surveillance (acepromazine, azaperone, celecoxib, fentanyl, fluphenazine, mepivacaine, methylphenidate and tripelennamine). In vitro samples were analyzed qualitatively alongside samples originating from in vivo administrations using LC-MS on a high resolution accurate mass Thermo Orbitrap Discovery instrument and by...
Winther L, Honoré Hansen S, Baptiste KE, Friis C.Doxycycline concentrations, following two types of oral administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. The oral bioavailability was estimated from plasma concentrations achieved after an intravenous study in two horses. Doxycycline (10 mg/kg) was administered either intragastric or as topdressing to nonfasted horses. Blood samples were collected for drug analysis, before and 11 times after administration during 24 h. PELF samples were collected by a tampon device four times after drug administration and analysed for do...
