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.
Oyarzun-Ampuero F, Vidal A, Concha M, Morales J, Orellana S, Moreno-Villoslada I.The treatment of skin wounds represents an important research area due to the important physiological and aesthetic role of this tissue. During the last years, nanoparticles have emerged as important platforms to treat skin wounds. Silver, gold, and copper nanoparticles, as well as titanium and zinc oxide nanoparticles, have shown potential therapeutic effects on wound healing. Due to their specific characteristics, nanoparticles such as nanocapsules, polymersomes, solid lipid nanoparticles, and polymeric nanocomplexes are ideal vehicles to improve the effect of drugs (antibiotics, growth fact...
Knych HK, Harrison LM, White A, McKemie DS.The use of isoflupredone acetate in performance horses and the scarcity of published pharmacokinetic data necessitate further study. The objective of the current study was to describe the plasma pharmacokinetics of isoflupredone acetate as well as time-related urine and synovial fluid concentrations following intra-articular administration to horses. Twelve racing-fit adult Thoroughbred horses received a single intra-articular administration (8 mg) of isoflupredone acetate into the right antebrachiocarpal joint. Blood, urine and synovial fluid samples were collected prior to and at various tim...
Laverty G, McCloskey AP, Gorman SP, Gilmore BF.The threat of antimicrobial resistance has placed increasing emphasis on the development of innovative approaches to eradicate multidrug-resistant pathogens. Biofilm-forming microorganisms, for example, Staphylococcus epidermidis and Staphylococcus aureus, are responsible for increased incidence of biomaterial infection, extended hospital stays and patient morbidity and mortality. This paper highlights the potential of ultrashort tetra-peptide conjugated to hydrophobic cinnamic acid derivatives. These peptidomimetic molecules demonstrate selective and highly potent activity against resistant b...
Giorgi M, De Vito V, Poapolathep A, Rychshanova R, Sgorbini M, Owen H.Flupirtine (FLU) is a non-opioid analgesic drug, with no antipyretic or anti-inflammatory effects, used in the treatment of a wide range of pain states in human beings. It does not induce the side effects associated with the classical drugs used as pain relievers. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy horses. Six mixed breed adult mares were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received ...
Lima AG, Costa LC, Alvarenga MA, Martins CB.The presence of anovulatory haemorrhagic follicles during the oestrous cycle of mares causes financial impacts, slowing conception and increasing the number of services per pregnancy. Non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam and phenylbutazone are used in the treatment of several disorders in mares, and these drugs can impair the formation of prostaglandins (PGs) and consequently interfere with reproductive activity. This study aimed to evaluate the effects of treatment with NSAIDs on the development of pre-ovulatory follicles in mares. In total, 11 mares were studied o...
Felippelli G, Cruz BC, Gomes LV, Lopes WD, Teixeira WF, Maciel WG, Buzzulini C, Bichuette MA, Campos GP, Soares VE, Bergamasco PL, de Oliveira GP....By means of parasitological necropsies, the present study aimed to evaluate, in six experiments, the degree of susceptibility or resistance of different helminth species which naturally infect horses to ivermectin 0.2 mg/kg, abamectin 0.2 mg/kg, moxidectin 0.4 mg/kg, trichlorfon 35 mg/kg, ivermectin 0.2 mg/kg+praziquantel 2.5 mg/kg, abamectin 0.2 mg/kg+praziquantel 2.5 mg/kg and ivermectin 0.2 mg/kg+6.6 mg/kg pyrantel. At experimental day zero, the horses were allocated to treatment groups based on average counts of strongylid eggs per gram of feces (EPG) obtained on days -3, -2 and -1. Oxyuri...
Derochette S, Serteyn D, Mouithys-Mickalad A, Ceusters J, Deby-Dupont G, Neven P, Franck T.Excessive neutrophil stimulation and reactive oxygen species (ROS) production are involved in numerous human or horse pathologies. The modulation of the neutrophil NADPH oxidase (NOX) has a great therapeutic potential since this enzyme produces superoxide anion whose most of the other ROS derive. The measurement of NOX activity by cell-free systems is often used to test potential inhibitors of the enzyme. A major drawback of this technique is the possible interferences between inhibitors and the probe, ferricytochrome c, used to measure the activity. We designed the "EquiNox2", a new pharmacol...
Hunter BG, Parker JE, Wehrman R, Stang B, Cebra CK.To determine synovial concentrations of morphine after intravenous regional limb perfusion (IVRLP) with morphine or morphine in combination with gentamicin in clinically healthy, standing sedated horses. Methods: Experimental. Methods: Adult horses (n = 6). Methods: IVRLP was performed using 0.1 mg/kg morphine (M) in standing sedated horses. After a 3-week washout period, IVRLP was performed on the same forelimb with a combination of 0.1 mg/kg morphine and 1 g gentamicin (M/G). Synovial fluid from the middle carpal joint of the perfused limb and jugular blood samples were collected i...
López-Sanromán FJ, Gómez Cisneros D, Varela del Arco M, Santiago Llorente I, Santos González M.The aim of the present study was to quantify by accelerometry the trotting pattern of adult horses sedated with two different doses of acepromazine, in order to assess the use of this drug in equine lameness evaluations. Methods: Seven mature horses were used and three treatments were administered to each horse: saline solution, acepromazine (0.01 mg/kg), and acepromazine (0.02 mg/kg). The portable gait analyzer used consisted of three orthogonal accelerometers that measure accelerations along the dorsoventral, longitudinal, and lateral axes. Baseline values were obtained and after treatment, ...
Giguère S, Macpherson ML, Benson SM, Cox S, McNaughten JW, Pozor MA.Pregnancy induces several physiologic changes that might impact the bioavailability, distribution, metabolism, and excretion of drugs. The objective of this study was to determine the effects of pregnancy on the disposition of oral firocoxib in mares. Seven pony mares received oral firocoxib paste at a dose of 0.1 mg/kg during late pregnancy and again 12 to 33 days postpartum. Firocoxib concentrations were measured in plasma by HPLC with ultraviolet detection. Maximum plasma concentrations were significantly lower in pregnant (50.0 ± 21.8 ng/mL) than in postpartum (73.7 ± 25.6 ng/mL) mares. ...
Underwood C, Pollitt CC, Metselaar JM, Laverman P, van Bloois L, van den Hoven JM, Storm G, van Eps AW.Liposomes are phospholipid nanoparticles used for targeted drug delivery. This study aimed to determine whether intravenous liposomes accumulate in lamellar tissue during laminitis development in horses so as to assess their potential for targeted lamellar drug delivery. Polyethylene-glycol (PEG) coated liposomes were prepared according to the film hydration method and labelled using (99m)Tc-hexamethyl-propylene-amine-oxime. Six horses received 10 g/kg oligofructose via nasogastric tube to induce laminitis, and four control horses received water via nasogastric tube. All horses received 300â...
Sokół R, Raś-Noryńska M, Michalczyk M, Jasiecka A, Ziółkowski H, Jaroszewski J.The aim of the present study was to determine the efficacy of ivermectin against Cyathostominae infections and to describe the drug's pharmacokinetic parameters during two seasonal deworming treatments in horses. The study was performed on warm-blooded mares aged 3-12 years weighing 450-550 kg. A single bolus of an oral paste formulation of ivermectin was administered at a dose of 0.2 mg/kg BW in spring and autumn. Fecal samples were tested before treatment and 1, 2, 3, 4, 6, 10, 20, 30, 40, 50, 60, 75 days after treatment. Ivermectin concentrations in blood samples collected before treatment,...
Vivancos M, Barker J, Engbers S, Fischer C, Frederick J, Friedt H, Rybicka JM, Stastny T, Banse H, Cribb AE.Meloxicam, a non-steroidal anti-inflammatory drug, is approved for use in horses in several countries, but an equine formulation is not available in North America. However, meloxicam is being used in an extra-label manner in horses in Canada. The purpose of this study, therefore, was to assess the bioequivalence of an approved oral meloxicam suspension (Metacam 15 mg/mL for horses; Boehringer Ingelheim Vetmedica GmBH, Ingelheim, Germany) from the European Union with human meloxicam tablets (Meloxicam 15 mg tablets; TEVA Canada, Toronto, Ontario) compounded with molasses to improve palatability...
Wong AS, Ho EN, Wan TS, Lam KK, Stewart BD.Bisphosphonates are used in the management of skeletal disorder in humans and horses, with tiludronic acid being the first licensed veterinary medicine in the treatment of lameness associated with degenerative joint disease. Bisphosphonates are prohibited in horseracing according to Article 6 of the International Agreement on Breeding, Racing and Wagering (published by the International Federation of Horseracing Authorities). In order to control the use of bisphosphonates in equine sports, an effective method to detect the use of bisphosphonates is required. Bisphosphonates are difficult-to-de...
Emmerich IU.In 2014, no new active pharmaceutical ingredients were released on the German market for horses and food producing animals. One established veterinary active pharmaceutical ingredient is avaibable for an additional species. The analgetic buprenorphine (Buprenodale® Multidose) has additionally been authorized for horses. Furthermore, four new preparations with a new pharmaceutical form, one drug with a new formulation, new galenics and a new indication, respectively, have recently been released to the market. Furthermore, the prostaglandin F2α analoque luprostiol is available again.
Garrison KL, Sahin S, Benet LZ.This study was conducted to determine the number of drugs exhibiting flip-flop pharmacokinetics following oral (p.o.) dosing from immediate-release dosage forms and if they exhibit a common characteristic that may be predicted based on BDDCS classification. The literature was searched for drugs displaying flip-flop kinetics (i.e., absorption half-life larger than elimination half-life) in mammals in PubMed, via internet search engines and reviewing drug pharmacokinetic data. Twenty two drugs were identified as displaying flip-flop kinetics in humans (13 drugs), rat (nine drugs), monkey (three ...
Underwood C, Collins SN, van Eps AW, Mills PC, Allavena RE, Bailey SR, Medina Torres CE, Meizler A, Pollitt CC.No validated laminitis drug therapy exists, yet pharmaceutical agents with potential for laminitis prevention have been identified. Many of these are impractical for systemic administration but may be effective if administered locally. This study compared intraosseous infusion of the distal phalanx (IOIDP) with systemic intravenous constant rate infusion (CRI) to determine which was more effective for lamellar marimastat delivery. Ultrafiltration probes were placed in both forefeet of five horses to collect lamellar interstitial fluid as lamellar ultrafiltrate (LUF). Marimastat solution (3.5â€...
Sykes BW, Underwood C, Greer R, McGowan CM, Mills PC.Omeprazole is widely used in the treatment of equine gastric ulcer syndrome. To date, little is known about the relative pharmacokinetics of the different formulations making comparisons between products difficult. The objectives of the study were to investigate the relative pharmacokinetics of five commercially available formulations of omeprazole in the horse and to test for bioequivalence of four of the formulations using one of the formulations as a reference standard. Twelve mature Thoroughbred horses were fasted for 16 h then administered 2 g of each formulation in a cross-over design. S...
Afonso T, Giguère S, Rapoport G, Barton MH, Coleman AE.Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. Objective: To determine the cardiovascular effects of pimobendan in healthy mature horses. Methods: Randomised experimental study. Methods: Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses ...
Casoni D, Spadavecchia C, Wampfler B, Thormann W, Levionnois OL.Intravenous anaesthetic drugs are the primary means for producing general anaesthesia in equine practice. The ideal drug for intravenous anaesthesia has high reliability and pharmacokinetic properties indicating short elimination and lack of accumulation when administered for prolonged periods. Induction of general anaesthesia with racemic ketamine preceded by profound sedation has already an established place in the equine field anaesthesia. Due to potential advantages over racemic ketamine, S-ketamine has been employed in horses to induce general anaesthesia, but its optimal dose remains und...
Hunter BG, Duesterdieck-Zellmer KF, Larson MK.Anecdotal accounts of tiludronate administration via intravenous regional limb perfusion (IVRLP) exist despite a lack of information regarding safety for synovial structures in the perfused area. The objective of this study was to determine whether tiludronate concentrations in synovial structures after IVRLP with low dose (0.5 mg, LDT) or high dose (50 mg, HDT) tiludronate remain below a value demonstrated in vitro to be safe for articular cartilage (<19,000 ng/ml), and to determine effects of tiludronate on synovial fluid cytology variables compared to saline perfused control limbs. Using...
Rizk MA, El-Sayed SA, Terkawi MA, Youssef MA, El Said el Sel S, Elsayed G, El-Khodery S, El-Ashker M, Elsify A, Omar M, Salama A, Yokoyama N....A rapid and accurate assay for evaluating antibabesial drugs on a large scale is required for the discovery of novel chemotherapeutic agents against Babesia parasites. In the current study, we evaluated the usefulness of a fluorescence-based assay for determining the efficacies of antibabesial compounds against bovine and equine hemoparasites in in vitro cultures. Three different hematocrits (HCTs; 2.5%, 5%, and 10%) were used without daily replacement of the medium. The results of a high-throughput screening assay revealed that the best HCT was 2.5% for bovine Babesia parasites and 5% for equ...
Cohen ND, Slovis NM, Giguère S, Baker S, Chaffin MK, Bernstein LR.Macrolide-resistant isolates of Rhodococcus equi are emerging, prompting the search for clinically effective alternative antimicrobials. Objective: The proportion of foals with ultrasonographic evidence of pneumonia presumed to be caused by R. equi that had a successful outcome when administered gallium maltolate (GaM) PO would not be more than 10% inferior (ie, lower) than that of foals receiving standard treatment. Methods: Fifty-four foals with subclinical pulmonary abscesses among 509 foals at 6 breeding farms in Kentucky. Methods: Controlled, randomized, prospective noninferiority study. ...
Janssen IJ, Krücken J, Demeler J, von Samson-Himmelstjerna G.P-glycoproteins (Pgps) are suspected to mediate drug extrusion in nematodes contributing to macrocyclic lactone resistance. This association was recently shown for Parascaris Pgp-11. Ivermectin resistance was correlated with the presence of three pgp-11 single nucleotide polymorphisms and/or increased pgp-11 mRNA levels. In the present study, the ability of Pgp-11 to modulate ivermectin susceptibility was investigated by its expression in a pgp-11-deficient Caenorhabditis elegans strain. Expression of Parascaris pgp-11 in two transgenic lines significantly decreased ivermectin susceptibility i...
Menendez MI, Phelps MA, Bertone AL.To the date, no reports exist of the pharmacokinetics (PK) of betamethasone (BTM) sodium phosphate and betamethasone acetate administered intra-articular (IA) into multiple joints in exercising horses. The purpose of the study was to determine the PK of BTM and HYD concentrations in plasma and urine after IA administration of a total of 30 mg BTM. Eight 4 years old Thoroughbred mares were exercised on a treadmill and BTM was administered IA. Plasma and urine BTM and HYD were determined via high performance liquid chromatography spectrometry for 6 weeks. Concentration-time profiles of BTM and H...
Wang CC, Hartmann-Fischbach P, Krueger TR, Wells TL, Simonson A, Compton JC.Due to opiorphin's analgesic and antidepressant functions, its illicit use is rumored in some racing jurisdictions. Opiorphin is very difficult to detect due to its hydrophilic nature and rapid degradation in plasma and urine samples. METHODOLOGY & RESULTS: We have developed a sensitive, reliable method for opiorphin detection and confirmation in equine samples, using EDTA to inhibit analyte degradation between the time of collection and analysis. Opiorphin was extracted by weak cation exchange followed by analysis using HILIC-MS/MS. The method was validated and the LOD was determined to b...
Bienert-Zeit A, Gietz C, Staszyk C, Kietzmann M, Stahl J, Ohnesorge B.To monitor concentrations of sulfadimidine in the paranasal sinus mucosa (PSM) of unsedated horses following IV administration of trimethoprim-sulfadimidine via in vivo microdialysis. Methods: 10 healthy adult horses. Methods: Concentric microdialysis probes were implanted into the subepithelial layers of the frontal sinus mucosa of standing sedated horses. Four hours after implantation, trimethoprim-sulfadimidine (30 mg/kg) was administered IV every 24 hours for 2 days; dialysate and plasma samples were collected at intervals during that 48-hour period and analyzed for concentrations of sulfa...
Qi M, Zhou H, Wang H, Wang R, Xiao L, Arrowood MJ, Li J, Zhang L.A total of 262 fecal specimens collected from grazing horses at five locations in Xinjiang, China were examined by PCR for Cryptosporidium spp. and Giardia duodenalis. The Cryptosporidium and G. duodenalis infection rates were 2.7% and 1.5%, respectively. Seven Cryptosporidium-positive specimens were found in foals (16.3%), and four G. duodenalis-positive specimens were found in mares (2.5%). Sequence analyses of 18S rRNA and gp60 genes revealed that seven animals were positive for the subtype VIaA15G4 of Cryptosporidium horse genotype. G. duodenalis assemblages A and B were identified by mole...
The intestinal tract is a rich and complex environment and its microbiota has been shown to have an important role in health and disease in the host. Several factors can cause disruption of the normal intestinal microbiota, including antimicrobial therapy, which is an important cause of diarrhea in horses. This study aimed to characterize changes in the fecal bacterial populations of healthy horses associated with the administration of frequently used antimicrobial drugs. Results: Twenty-four adult mares were assigned to receive procaine penicillin intramuscularly (IM), ceftiofur sodium IM, tr...
Giguère S, Burton AJ, Berghaus LJ, Haspel AD.The objective of this study was to compare the pharmacokinetics of minocycline in foals vs. adult horses. Minocycline was administered to six healthy 6- to 9-week-old foals and six adult horses at a dose of 4 mg/kg intragastrically (IG) and 2 mg/kg intravenously (i.v.) in a cross-over design. Five additional oral doses were administered at 12-h intervals in foals. A microbiologic assay was used to measure minocycline concentration in plasma, urine, synovial fluid, and cerebrospinal fluid (CSF). Liquid chromatography-tandem mass spectrometry was used to measure minocycline concentrations in ...
Adams RJ, Mathys DA, Mollenkopf DF, Whittle A, Daniels JB, Wittum TE.The emergence of bacterial resistance to carbapenem antibiotics is an urgent public health threat. Carbapenem drugs are a last resort treatment option for life-threatening infections. The frequent use of broad-spectrum antibiotics to treat hospitalized patients provides significant selection pressure favoring the emergence and dissemination of resistant organisms, including carbapenem-resistant Enterobacteriaceae (CRE). CREs have been reported in animal populations, but only rarely in horses. Our objective was to determine the prevalence of CRE in the environment of a referral equine specialty...
Capponi L, Schmitz A, Thormann W, Theurillat R, Mevissen M.To investigate cytochrome P450 (CYP) enzymes involved in metabolism of racemic and S-ketamine in various species and to evaluate metabolic interactions of other analgesics with ketamine. Methods: Human, equine, and canine liver microsomes. Methods: An analgesic was concurrently incubated with luminogenic substrates specific for CYP 3A4 or CYP 2C9 and liver microsomes. The luminescence signal was detected and compared with the signal for negative control samples. Ketamine and norketamine enantiomers were determined by use of capillary electrophoresis. Results: A concentration-dependent decrease...
Anwaar F, Ijaz M, Rasheed H, Shah SFA, Haider SAR, Sabir MJ.The purpose of the current study was to investigate the nasal colonization and drug resistance profile of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and vancomycin-resistant S. aureus (VRSA) in donkeys (n =63), mules (n = 42), and horses (n = 98). MRSA and VRSA were confirmed based on phenotypic and molecular methods, followed by phylogenetic analysis. Furthermore, the association of various animal and management-based risk factors with S. aureus colonization was also evaluated. The presence of nuc gene on polymerase chain reaction showed an overall prevalence of 42.86%...
Szöke MO, Blais D, Cuvelliez SG, Lavoie JP.To evaluate the cardiovascular and respiratory effects of buprenorphine administered intravenously in clinically normal horses and horses with chronic obstructive pulmonary disease (COPD). Methods: 5 clinically normal horses and 5 horses with COPD that were in partial clinical remission (period A) or were having an acute attack of airway obstruction (period B). Methods: Pulmonary function testing, arterial blood gas analysis, and arterial blood pressure measurements were performed before and after a single intravenous bolus of buprenorphine (3 microg/kg of body weight). Respiratory rate (f), t...
Steel R, Timms M, Levina V, Vine J.The Dermorphins are a family of peptides that act as potent agonists of the opioid μ receptor. Originally identified as a seven amino acid peptide on the skin of the South American Phyllomedusa frog, peptide chemists have since developed a large number of Dermorphin variants, many with superior opioid activity to the original peptide. Dermorphins are unique among the peptide opioid agonists as they appear to have a limited ability to cross the blood brain barrier, producing effects on both the central and peripheral nervous systems. It is this ability of Dermorphins to provide central anaesth...
Gold JR, Grubb TL, Green S, Cox S, Villarino NF.In humans, gabapentin an analgesic, undergoes non-proportional pharmacokinetics which can alter efficacy. No information exists on the pharmacokinetics of dosages >20 mg/kg, escalating dosages or dose proportionality of gabapentin in horses. Objective: Gabapentin exposure in plasma would not increase proportionally relative to the dose in horses receiving dosages ≥20 mg/kg. To assess the plasma pharmacokinetics of gabapentin after nasogastric administration of gabapentin at dosages of 10 to 160 mg/kg in adult horses. Methods: Nine clinically healthy adult Arabian and Quarter Horses....
Steffey EP, Pascoe PJ.To quantitate the dose- and time-related magnitude of the anesthetic sparing effect of, and selected physiological responses to detomidine during isoflurane anesthesia in horses. Methods: Randomized cross-over study. Methods: Three, healthy, young adult horses weighing 485 ± 14 kg. Methods: Horses were anesthetized on two occasions to determine the minimum alveolar concentration (MAC) of isoflurane in O and then to measure the anesthetic sparing effect (time-related MAC reduction) following IV detomidine (0.03 and 0.06 mg kg). Selected common measures of cardiopulmonary function, blood glucos...
Jaussaud P, Guieu D, Bellon C, Barbier B, Lhopital MC, Sechet R, Courtot D, Toutain PL.The pharmacokinetics of tolfenamic acid were studied in five ponies after an intravenous (iv) administration (2 mg/kg bodyweight [bwt]) and in four horses after an oral administration (30 mg/kg bwt) of tolfenamic acid. The plasma levels were determined by high pressure liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). For the iv administration, a three-compartment model was used to represent the plasma concentration-time curve of the drug. The elimination half-life of the compound was 6.1 +/- 1.5 h, the total body clearance was 72.4 +/- 16.7 ml/kg bwt/h and the ste...
Sams RA, Ruoff WW.The pharmacokinetics and bioavailability of cefazolin given (IV, IM) to horses at the dosage of 11 mg/kg were investigated. The disposition of cefazolin given by IV route was characterized by a rapid disposition phase with a half-life of 5 to 10 minutes and a subsequent slower elimination phase with a half-life of 35 to 46 minutes. The total plasma clearance of cefazolin averaged 5.51 ml/min/kg and was due mainly to renal clearance (5.39 ml/min/kg) of unchanged drug. The volume of distribution at steady-state averaged 188 ml/kg. Plasma protein binding of cefazolin at a concentration of 10 micr...
Fischer B, Clark-Price S.Anesthetizing the neonatal foal presents significant challenges as a result of physiologic differences from the adult equine. This article gives the reader an overview of these differences and the impact they have on anesthetic drug selection, monitoring, and support of the equine neonate. Special emphasis is directed to the sick neonate and appropriate preparation and maintenance of anesthesia in the face of commonly presented disease conditions.
Pellegrini-Masini A, Poppenga RH, Sweeney RW.An injectable preparation of flunixin meglumine was administered orally and intravenously at a dose of 1.1 mg/kg to six healthy adult horses in a cross-over design. Flunixin meglumine was detected in plasma within 15 min of administration and peak plasma concentrations were observed 45-60 min after oral administration. Mean bioavailability of the oral drug was 71.9 +/- 26.0%, with an absorption half-life of 0.76 h. The apparent elimination half-life after oral administration was 2.4 h. The injectable preparation of flunixin meglumine is suitable for oral administration to horses.
Vatistas NJ, Snyder JR, Hildebrand SV, Harmon FA, Woliner MJ, Barry SJ, Nieto J, Henry P, Enos LR, Magliano D, Brown SA, Drake C.To determine the effects of the 21-aminosteroid, U-74389G, on reperfusion of the equine jejunum, using total (TVO) and partial (PVO) vascular occlusion during the ischemic period. Methods: TVO: 16 healthy horses were randomly allotted to 3 groups-4 horses received the vehicle alone, 6 horses received a low dosage (3 mg/kg o body weight), and 6 horses a high dosage (10 mg/kg) of U-7438G. PVO: 10 healthy horses were randomly allotted to 2 groups--5 horses received the vehicle alone, and 5 horses received the low dosage (3 mg/kg) of U-74389G. Methods: TVO was induced for 1 hour followed by 2 hour...
von Fellenberg RL, Jordan JC, Ludwig B, Rehm WF.Aditoprim, a broad spectrum antimicrobial agent acting as a reversible dihydrofolate reductase inhibitor, was intravenously injected into four 12 to 24-year old horses at a dosage of 5 mg/kg b. w. Blood samples were collected over a 48-hour period after drug injection, and the separated plasma samples were assayed for aditoprim by high performance liquid chromatography. The body temperature, heart rate, respiration rate, and behaviour were recorded during the experiment. The bilirubin and urea concentrations were also determined in several plasma samples, and liver function tests were carried ...
Kowalczyk L, Steblaj B, Schauvliege S, Schramel JP, Pavlidou K, Savvas I, Duchateau L, Gasthuys F, Moens Y.To compare breathing patterns and transdiaphragmatic pressure during total intravenous (TIVA) and isoflurane anaesthesia in ponies. Methods: Experimental, cross-over study. Methods: Six healthy ponies weighing 286 (233-388) ± 61 kg, age 13 (9-16) ± 3 years. Methods: Following premedication with romifidine [80 μg kg(-1) intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg(-1) IV) and ketamine (2.5 mg kg(-1) IV) and maintained with either isoflurane (Fe'Iso = 1.1%) (T-ISO) or an IV combination of romifidine (120 μg kg(-1) per hour), midazolam (0.09 mg kg(-1) hour(-...
Flynn H, Cenani A, Brosnan RJ, DiMaio Knych HK, de Araujo Aguiar AJ.To determine the pharmacokinetics and pharmacodynamics of high-concentration formulation of buprenorphine (1.8 mg mL; Simbadol) following subcutaneous (SC) administration in horses. Methods: Prospective, randomized, crossover trial. Methods: A group of six healthy adult horses weighing 521-602 kg. Methods: On three occasions, Simbadol (0.005 mg kg; treatment S5), (0.0025 mg kg; treatment S2.5) or saline (treatment SAL) were administered SC at least 7 days apart in random order. Electrical nociceptive threshold (ENT) measured on the neck region, physiologic variables, locomotor activity, degree...
Torbert BJ, Kramer BS, Klei TR.A controlled test was used in ponies to compare the antiparasitic efficacy of ivermectin (22,23-dihydro-avermectin B1) in an injectable micelle solution administered IM with the efficacy of the same drug in an oral paste formulation. Parasite infections were naturally acquired in southern Louisiana. The drug was tested in both formulations at a dosage level of 0.2 mg/kg of body weight. Ivermectin in both formulations tested had an efficacy greater than 98% against Gasterophilus intestinalis and G nasalis larvae. Trichostrongylus axei, Habronema spp, Strongylus vulgaris, S. edentatus, and speci...
Hall LW, Taylor PM.One hundred anaesthetics were administered in a clinical trial to 95 equine patients, ranging in age from nine months to 19 years and in weight from 140 to 1270 kg, undergoing a variety of surgical procedures. Acepromazine maleate premedication (0.01 to 0.03 mg per kg intramuscularly) was given to seven animals, the remainder were not premedicated. Xylazine (1.1 mg per kg) was injected intravenously over a two minute period and after a pause of two minutes ketamine (2.2 mg per kg) was injected rapidly by the same route. For 30 procedures no other anaesthetic was given but in 59 cases anaesthes...
Welsh CE, Parkin TDH, Marshall JF.As antimicrobial resistant bacterial strains continue to emerge and spread in human and animal populations, understanding prescription practices is key in benchmarking current performance and setting goals. Antimicrobial prescription (AP) in companion veterinary species is widespread, but is neither monitored nor restricted in the USA and Canada. The veterinary use of certain antimicrobial classes is discouraged in some countries, in the hope of preserving efficacy for serious human infections. Objective: The aim of this study was to ascertain the rate of prescription of a number of 'reserved'...
Matthews JB, McArthur C, Robinson A, Jackson F.Cyathostomins are the primary parasitic pathogens of equids. For over 40 years, these nematodes have been controlled using broad spectrum anthelmintics. Three classes of anthelmintic are currently available for this use but, unfortunately, resistance to each of these has now been recorded in cyathostomin populations. As part of an optimal strategy to control cyathostomin infections in the field, it will be important to identify drug-resistant worms at as early a stage as possible. This objective needs to be supported by methodologies that will allow the accurate comparison of anthelmintic resi...
DiMaio Knych HK, DeStefano Shields C, Buckpitt AR, Stanley SD.Substantial gaps exist in our knowledge of the metabolic clearance of therapeutic agents in horses. Accordingly, a cytochrome P450 monooxygenase in the 2C family was cloned from an equine liver, sequenced and expressed in a baculovirus expression system. Catalytic activities of the recombinant protein were measured with a number of substrates. The protein, assigned CYP2C92, displayed optimal catalytic activity with diclofenac using molar ratios of CYP2C92 to NADPH CYP450 reductase of 1:18. Addition of cytochrome b(5) to diclofenac incubations had no significant effect on metabolic turnover. CY...
Luo Y, Uboh CE, Soma LR, Guan F, Rudy JA, Tsang DS.This method describes the simultaneous separation, identification, quantification and confirmation of betamethasone (BTM) and dexamethasone (DXM) in equine plasma by liquid chromatography (LC) integrated with multidimensional tandem mass spectrometry. Analytes were directly extracted from equine plasma by methyl tert-butyl ether (MTBE). The residues were reconstituted with sample solvent. LC separation of the analytes was performed on a Hypercarb column using acetonitrile/water/formic acid (95:5:0.5, v/v/v) as the mobile phase. Sample screening, quantification and confirmation were performed i...
Linardi RL, Stokes AM, Andrews FM.Methadone is an effective analgesic opioid that may have a place for the treatment of pain in horses. However, its absorption seems to be impaired by the presence of a transmembrane protein, P-glycoprotein, present in different tissues including the small intestine in other species. This study aims to determine the effect of the P-glycoprotein on methadone flux in the equine intestinal mucosa, as an indicator of in vivo drug absorption. Jejunum tissues from five horses were placed into the Ussing chambers and exposed to methadone solution in the presence or absence of Rhodamine 123 or verapami...
Kwok WH, Choi TLS, Kwok KY, Chan GHM, Wong JKY, Wan TSM.The high sensitivity of ultra high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS) allows the identification of many prohibited substances without pre-concentration, leading to the development of simple and fast 'dilute-and-shoot' methods for doping control for human and equine sports. While the detection of polar drugs in plasma and urine is difficult using liquid-liquid or solid-phase extraction as these substances are poorly extracted, the 'dilute-and-shoot' approach is plausible. This paper describes a 'dilute-and-shoot' UHPLC-HRMS screening me...
Skarda RT, Muir WW.To determine the analgesic, hemodynamic, and respiratory effects induced by caudal epidural administration of meperidine hydrochloride in mares. Methods: 7 healthy mares. Methods: Each mare received meperidine (5%; 0.8 mg/kg of body weight) or saline (0.9% NaCl) solution via caudal epidural injection on 2 occasions. At least 2 weeks elapsed between treatments. Degree of analgesia in response to noxious electrical, thermal, and skin and muscle prick stimuli was determined before and for 5 hours after treatment. In addition, cardiovascular and respiratory variables were measured and degree of se...
Colglazier ML, Enzie FD, Kates KC.The comparative efficacy of four benzimidazoles against gastrointestinal parasites of ponies was evaluated by the critical test method. Mebendazole (8.8 mg/kg), cambendazole (20 mg/kg), fenbendazole (5 mg/kg), and albendazole (2.5 and 5 mg/kg) given in single oral doses were highly effective against adult large strongylids (Strongylus vulgaris, S. endentatus, S. equinus) and adult small strongylids (genera identified in order of frequency: Cylicostephanus, Cylicocyclus, Cyathostomum, Triodontophorus, Poteriostomum, Oesophagodontus, Cylicodontophorus, Gyalocephalus, and Craterostomum). Limited ...
Davis JL, Papich MG, Morton AJ, Gayle J, Blikslager AT, Campbell NB.The purpose of this study was to determine the pharmacokinetics of etodolac following oral and intravenous administration to six horses. Additionally, in vitro cyclooxygenase (COX) selectivity assays were performed using equine whole blood. Using a randomized two-way crossover design, horses were administered etodolac (20 mg/kg) orally or intravenously, with a minimum 3-week washout period. Plasma samples were collected after administration for analysis using high pressure liquid chromatography with ultraviolet detection. Following intravenous administration, etodolac had a mean plasma half-li...
Smith KM, Pucket JD, Gilmour MA.To describe a reproducible technique for intrastromal injection in the standing horse for treatment of corneal stromal abscessation. Methods: A retrospective clinical study addressing the history, treatment, and outcome of six equids (six eyes) that received intrastromal voriconazole injection. Methods: Equids having a deep stromal abscess suspected to be of fungal origin were administered intrastromal injection of 5% voriconazole solution under standing sedation in an effort to bring about enhanced resolution of clinical disease. Results: Intracorneal administration of 5% voriconazole solutio...
Meucci V, Minunni M, Vanni M, Sgorbini M, Corazza M, Intorre L.Detection of nonsteroidal anti-inflammatory drugs (NSAIDs) in equine plasma is a significant analytical problem in veterinary anti-doping controls. Results: A new HPLC method coupled to selective extraction with molecularly imprinted polymers was developed for the simultaneous determination in equine plasma of the NSAIDs phenylbutazone, flunixin, oxyphenbutazone, ketoprofen and naproxen. The analytical performances of the method have been evaluated both in standard solutions and equine plasma samples. Recovery: Molecularly imprinted polymers solid-phase extraction for all NSAIDs was >94% with ...
