Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Drug
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.
Comparison of the influence of two different constant-rate infusions (dexmedetomidine versus morphine) on anaesthetic requirements, cardiopulmonary function and recovery quality in isoflurane anaesthetized horses. Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinded, clinical study. Horses were randomly allocated to receive a constant rate infusion (CRI) of morphine or dexmedetomidine. After induction, anaesthesia was maintained with isoflurane in oxygen/air and mechanical ventilation applied. The end-tidal isoflurane concentration (FÉISO) was initially set at 0.9% and adjusted by the anaesthetist, to maintain a light surgical plane of anaesthesia, according to an objective flow-chart. The cardiopulmonary function was only minimally different between groups...
Therapeutic plasma concentrations of epsilon aminocaproic acid and tranexamic acid in horses. Antifibrinolytic drugs such as epsilon aminocaproic acid (EACA) and tranexamic acid (TEA) are used to treat various bleeding disorders in horses. Although horses are hypofibrinolytic compared to humans, dosing schemes have been derived from pharmacokinetic studies targeting plasma concentrations in humans. Objective: We hypothesized therapeutic plasma concentrations of antifibrinolytic drugs in horses would be significantly lower than in humans. Our objective was to use thromboleastography (TEG) and an in vitro model of hyperfibrinolysis to predict therapeutic concentrations of EACA and TEA in...
Minimum end-tidal sevoflurane concentration necessary to prevent movement during a constant rate infusion of morphine, or morphine plus dexmedetomidine in ponies. To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those of morphine alone on the minimum end-tidal sevoflurane concentration necessary to prevent movement (MACNM ) in ponies. Methods: Prospective, randomized, crossover, 'blinded', experimental study. Methods: Five healthy adult gelding ponies were anaesthetized twice with a 3-week washout period. Methods: After induction of anaesthesia with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (Fe'SEVO 2.5%) i...
A pilot phase II study of the efficacy and biosafety of doxorubicin chemotherapy in tumor-bearing equidae. The efficacy and biosafety of a previously established tolerable dosage of doxorubicin have not been established in horses. Objective: To provide preliminary evidence of the efficacy of doxorubicin in tumor-bearing horses, explore drug pharmacokinetics profile, and estimate period of risk of exposure to drug residues. Methods: Twelve horses with 37 tumors. Methods: Treatment protocol included 6 treatments at 3-week intervals. Eight horses were uniformly treated at a dosage of 70 mg/m(2) and 4 horses received 4 of 6 treatment cycles at 70 mg/m(2) . Clinical signs, tumor responses, and toxicoses...
Evaluation of efficacy of mineral oil, charcoal, and smectite in a rat model of equine cantharidin toxicosis. The efficacy of orally administered therapeutics for the treatment of cantharidin intoxication has not been evaluated in controlled studies. Objective: To develop a model of acute cantharidin intoxication in laboratory rats and to evaluate in this model the relative efficacy of 3 gastrointestinal therapies used to treat equine cantharidin toxicosis. Methods: Sixty-four male Sprague-Dawley rats. Methods: A blinded, randomized, controlled study was performed on rats surgically implanted with telemetry transmitters for evaluating heart rate, locomotor activity, and body temperature. Orogastric ad...
Temporal trends in prevalence of bacteria isolated from foals with sepsis: 1979-2010. Sepsis is an important cause of death in foals. Knowledge of which pathogens are likely to be involved is important for selection of antimicrobial drugs for initial treatment. Objective: To identify temporal trends in prevalence of bacteria isolated from foals with sepsis between 1979 and 2010. Methods: Retrospective review of medical records. Methods: All foals ≤30 days of age presented to the Veterinary Medical Teaching Hospital (VMTH) at the University of California, Davis between 1979 and 2010, with a diagnosis of sepsis confirmed by culture of bacteria from blood or internal organs (ant...
Temporal trends in in vitro antimicrobial susceptibility patterns of bacteria isolated from foals with sepsis: 1979-2010. Monitoring the development of antimicrobial resistance is important for the rational selection of appropriate antimicrobial drugs to initiate treatment of foals with sepsis. Objective: To identify temporal trends in antimicrobial susceptibility patterns of bacteria isolated from foals with sepsis. Methods: Retrospective review of medical records. Methods: Foals aged <30 days with a diagnosis of sepsis, confirmed by culture of bacteria, were included. Susceptibility data, expressed as minimum inhibitory concentrations (MICs) (MIC50 , MIC90 , MIC range) and percent of isolates that were susce...
Disposition of firocoxib in equine plasma after an oral loading dose and a multiple dose regimen. The objective of this study was to determine if a single loading dose (LD), 3× the label dose of firocoxib oral paste, followed by nine maintenance doses at the current label dose achieves and maintains near steady state concentrations. Six healthy, adult mares were administered 0.3mg/kg of firocoxib on Day 0, and 0.1 mg/kg 24 h later on Day 1, and at 24 h intervals from Day 2 to Day 9, for a total of 10 doses. Blood samples were collected throughout the study. The mean firocoxib maximum plasma concentration and standard deviation was 199±97 ng/mL, 175±44 ng/mL and 183±50 ng/mL after the L...
Indenopyride derivative RTI-4587-073(l): a candidate for male contraception in stallions. The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baselin...
Voltage changes in the lithium dilution cardiac output sensor after exposure to blood from horses given xylazine. In a previous in vitro study using saline medium, the authors showed that certain drugs changed the voltages of lithium dilution cardiac output (LiDCO) sensors and also influenced their accuracy in measuring lithium concentrations. These two parameters correlated and so we examined whether such drug-sensor interaction exists when LiDCO sensor was exposed to xylazine in blood. Methods: Five healthy adult warm-blood horses were injected with 0.5 mg kg(-1) xylazine i.v. Physiological saline solution and venous blood were consecutively sampled through the same LiDCO sensor at 60, 45, 30, 15, and 0...
Rapid detection and identification of Theileria equi and Babesia caballi by high-resolution melting (HRM) analysis. 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...
Effects of clopidogrel on the platelet activation response in horses. To evaluate the platelet activation response before and after treatment with clopidogrel in horses. Methods: 12 healthy adult mares. Methods: In a masked study, horses (6/group) were randomly allocated to alternately receive placebo or clopidogrel via nasogastric tube at a loading dose of 4 mg/kg followed by 2 mg/kg every 24 hours. Blood samples were collected before and 72 hours after initiation of treatment for ADP- and collagen-induced light transmission aggregometry; determination of closure time in collagen-ADP cartridges; modified thrombelastography for comparison of maximal amplitudes g...
In vitro effects of lidocaine on contractility of circular and longitudinal equine intestinal smooth muscle. The purpose of the study was to compare the contractility-enhancing effects of lidocaine in equine jejunal circular (CSM) and longitudinal smooth muscle (LSM) in vitro. In previous studies, more pronounced effects of lidocaine were observed in ischaemia-reperfusion (IR) injured smooth muscle. Therefore in this study, effects were examined in both non-injured control tissues and tissues challenged by a defined, artificial IR injury. Isometric contractile performance of CSM and LSM, assessed by frequency (F), amplitude (A) and mean active force (MAF) of contractions, was defined as contractility...
[New drugs for horses and production animals in 2012]. In 2012, two newly developed active pharmaceutical ingredients for horses and food producing animals were released on the German market for veterinary drug products. Those are the parenterally applicable first generation cephalosporin Cefalonium (Cepravin®) and the nonsteroidal anti-inflammatory drug Suxibuzone (Danilon®). Furthermore, one established veterinary active pharmaceutical ingredient is applicable to additional species: The anticoccidial Amprolium (Eimeryl®) has again been authorized for chicken and turkeys. Additionally, two veterinary drugs with a new formulation as well as thr...
Pharmacodynamic evaluation of 4 angiotensin-converting enzyme inhibitors in healthy adult horses. Angiotensin-converting enzyme (ACE) inhibitors are used in horses with cardiovascular disorders despite the paucity of available data regarding their efficacy. Objective: The degree of serum ACE inhibition varies considerably between drugs. Methods: Eight healthy adult horses. Methods: Randomized prospective study. Horses were fasted overnight prior to receiving one of 4 ACE inhibitors intragastrically, administered at one of 2 dosages, using a randomized Latin square design (benazepril: 0.5 and 0.25 mg/kg; ramipril: 0.3 and 0.1 mg/kg; quinapril: 0.25 and 0.125 mg/kg; perindopril: 0.1 and 0.05...
Detection and elimination profile of cathinone in equine after norephedrine (Propalin®) administration using a validated liquid chromatography-tandem mass spectrometry method. Cathinone is the principal psychostimulant present in the leaves of khat shrub, which are widely used in East Africa and the Arab peninsula as an amphetamine-like stimulant. Cathinone readily undergoes metabolism in vivo to form less potent cathine and norephedrine as the metabolites. However, the presence of cathine and norephedrine in biological fluids cannot be used as an indicator of cathinone administration. The metabolism of pseudoephedrine and ephedrine, commonly used in cold and allergy medications, also produces cathine and norephedrine, respectively, as the metabolites. Besides, cath...
Monitoring the endogenous steroid profile disruption in urine and blood upon nandrolone administration: An efficient and innovative strategy to screen for nandrolone abuse in entire male horses. Nandrolone (17β-hydroxy-4-estren-3-one) is amongst the most misused endogenous steroid hormones in entire male horses. The detection of such a substance is challenging with regard to its endogenous presence. The current international threshold level for nandrolone misuse is based on the urinary concentration ratio of 5α-estrane-3β,17α-diol (EAD) to 5(10)-estrene-3β,17α-diol (EED). This ratio, however, can be influenced by a number of factors due to existing intra- and inter-variability standing, respectively, for the variation occurring in endogenous steroids concentration levels in a si...
Pharmacokinetics and thrombolytic effects of the recombinant tissue-type plasminogen activator in horses. To test the efficacy of the recombinant tissue-type plasminogen activator (rt-PA) alteplase in horses, the thrombolytic effect was tested in in vitro generated equine thrombi. The extent of lysis was determined by measuring the decrease in thrombi weight over a period of 4 hours. In vivo pharmacokinetics of alteplase were determined in 6 healthy horses. A single dose (1 mg/kg) was applied via intravenous infusion over a period of 30 minutes Coagulation-related variables, blood count and clinical parameters were taken before the treatment and until 48 h after treatment. In addition, plasma rt-P...
A clinician’s guide to factors affecting withdrawal times for equine therapeutic medications. Equine forensic science can now detect concentrations down to 25 femtograms/mL (parts per quadrillion, ppq) or less in blood and urine. As such, horsemen are increasingly at risk of inadvertent 'positives' due to therapeutic medication 'overages' or trace identifications of dietary or environmental substances. Reviewed here are the factors which determine detection times and 'withdrawal times' for substances administered to horses. Withdrawal times are affected by many factors, including dose, formulation, route and frequency of administration, bioavailability, plasma half-life, sensitivity of...
Evaluation of the conjunctival fungal flora and its susceptibility to antifungal agents in healthy horses in Switzerland. To characterize the conjunctival fungal flora and to determine the susceptibility of 2 isolated molds to antifungal drugs in samples of 64 healthy horses from The National Stud in Switzerland. Methods: Conjunctival cytobrush samples were collected from both eyes of 64 ophthalmologically normal horses in August 2012 and subsequently cultured on Sabouraud's agar medium. Growing fungi were identified and counted. Etests or broth microdilution tests for Aspergillus fumigatus and Eurotium amstelodami were carried out to determine antifungal drug sensitivity. These species had previously been detect...
Treatment of immune-mediated keratitis in horses with episcleral silicone matrix cyclosporine delivery devices. 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...
Induction of cytochrome P450 enzymes in primary equine hepatocyte culture. In this study, we established cell culture conditions for primary equine hepatocytes allowing cytochrome P450 enzyme (CYP) induction experiments. Hepatocytes were isolated after a modified method of Bakala et al. (2003) and cultivated on collagen I coated plates. Three different media were compared for their influence on morphology, viability and CYP activity of the hepatocytes. CYP activity was evaluated with the fluorescent substrate 7-benzyloxy-4-trifluoromethylcoumarin. Induction experiments were carried out with rifampicin, dexamethasone or phenobarbital. Concentration-response curves for...
In vivo and in vitro evaluation of the effects of domperidone on the gastrointestinal tract of healthy horses. To determine the effects of domperidone on in vivo and in vitro measures of gastrointestinal tract motility and contractility in healthy horses. Methods: 18 adult horses and tissue samples from an additional 26 adult horses. Methods: Domperidone or placebo paste was administered to healthy horses in a 2-period crossover study. Gastric emptying was evaluated after oral administration of domperidone paste (1.1 or 5.0 mg/kg) or placebo paste by means of the acetaminophen absorption test in 12 horses. Frequency of defecation, weight of feces produced, fecal moisture, and stomach-to-anus transit ti...
Disposition of methylprednisolone acetate in plasma, urine, and synovial fluid following intra-articular administration to exercised thoroughbred horses. Methylprednisolone acetate (MPA) is commonly administered to performance horses, and therefore, establishing appropriate withdrawal times prior to performance is critical. The objectives of this study were to describe the plasma pharmacokinetics of MPA and time-related urine and synovial fluid concentrations following intra-articular administration to sixteen racing fit adult Thoroughbred horses. Horses received a single intra-articular administration of MPA (100 mg). Blood, urine, and synovial fluid samples were collected prior to and at various times up to 77 days postdrug administration a...
The pharmacokinetics of methocarbamol and guaifenesin after single intravenous and multiple-dose oral administration of methocarbamol in the horse. A simple LC/MSMS method has been developed and fully validated to determine concentrations and characterize the concentration vs. time course of methocarbamol (MCBL) and guaifenesin (GGE) in plasma after a single intravenous dose and multiple oral dose administrations of MCBL to conditioned Thoroughbred horses. The plasma concentration-time profiles for MCBL after a single intravenous dose of 15 mg/kg of MCBL were best described by a three-compartment model. Mean extrapolated peak (C0 ) plasma concentrations were 23.2 (± 5.93) μg/mL. Terminal half-life, volume of distribution at steady-state...
Mutant prevention concentration and mutant selection window for 10 antimicrobial agents against Rhodococcus equi. The objectives of this study were to determine the mutant prevention concentration (MPC), time above the MPC and mutant selection window for 10 antimicrobial agents against Rhodococcus equi and to determine if the combination of a macrolide with rifampin would decrease emergence of resistant mutants. Antimicrobial agents investigated (erythromycin, clarithromycin, azithromycin, rifampin, amikacin, gentamicin, enrofloxacin, vancomycin, imipenem, and doxycycline) were selected based on in vitro activity and frequency of use in foals or people infected with R. equi. Each antimicrobial agent or co...
Efficacy of cyclo-oxygenase inhibition by two commercially available firocoxib products in horses. 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...
Nociceptive thermal threshold testing in horses – effect of neuroleptic sedation and neuroleptanalgesia at different stimulation sites. Aim of the study was to compare the effect of neuroleptic sedation with acepromazine and neuroleptanalgesia with acepromazine and buprenorphine on thermal thresholds (TT) obtained at the nostrils and at the withers. The study was carried out as a randomized, blinded, controlled trial with cross-over design. Thermal thresholds were determined by incremental contact heat applied to the skin above the nostril (N) or the withers (W). Eleven horses were treated with saline (S), acepromazine (0.05 mg/kg) (ACE) or acepromazine and buprenorphine (0.0075 mg/kg) (AB) intravenously (IV). Single stimula...
