Pharmaceuticals in equine medicine encompass a wide range of drugs and therapeutic agents used to treat various conditions in horses. These substances include analgesics, anti-inflammatories, antibiotics, sedatives, and anthelmintics, among others. Each class of pharmaceuticals is designed to address specific health issues, such as pain management, infection control, or parasitic infestations. The pharmacokinetics and pharmacodynamics of these drugs can vary significantly between horses and other species, necessitating careful consideration of dosage and administration methods. This page compiles peer-reviewed research studies and scholarly articles that explore the development, efficacy, safety, and regulatory aspects of pharmaceuticals used in equine healthcare.
Allen RG.The presently used procedures for the colorimetric determination of conjugated estrogens (equine) have been modified for the assay of tablets, capsules, liquids, and creams of low declaration per dosage unit. Modifications in sample chromatographic column preparation and elution have provided a more efficient extraction of the steroids.
Appolonova SA, Baranov PA, Mesonzhnik NV, Brazhnikova DO, Rodchenkov GM.A method is described for the determination of mesocarb abuse in equestrian sport by combining gradient liquid chromatography and electrospray ionization tandem mass spectrometry. Mesocarb was administrated orally to two horses at a dose of 50 µg/kg. Urine samples were collected up to 120 h post administration. Hydrolyzed and conjugated urine fractions were handled using liquid-liquid extraction (LLE). The identity of the parent drug and metabolites was confirmed using liquid chromatography combined with tandem mass spectrometry (MS/MS). Mesocarb and seven metabolites were detected in horse...
Hertzsch R, Emmerich IU, Lachenmeier DW, Sproll C, Monakhova YB, Aboling S, Bachmann U, Vervuert I.Opioid alkaloids were identified in the urine of horses during an anti-doping control and in a case of intoxication. In both cases, it was suspected that the horses had ingested poppy-contaminated feed. To verify this suspicion, possible opioid alkaloid sources in Germany were identified through a literature research. Additionally, the contaminated feed was botanically and chemically analysed. The results indicated that both cases were most probably caused by the poppy in the feed. This highlights the previously underestimated risk of an intake of poppy-contaminated feed in horses. Recommendat...
Brown MP, Kelly RH, Gronwall RR, Stover SM.Six healthy adult mares were given a single IV dose (25 mg/kg of body weight) of chloramphenicol sodium succinate. Chloramphenicol concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The highest measured serum chloramphenicol concentration was 6.21 micrograms/ml at 0.5 hour. Chloramphenicol was detected in synovial and peritoneal fluids, with mean peak concentrations of 3.89 micrograms/ml and 3.50 micrograms/ml, respectively, at 0.5 hour. Serum and synovial concentrations declined rapidly and were not measurable at 3 hours. Chloram...
Shank BR, Ofner CM.Pergolide mesylate (proprietary name Permax) is used to treat equine Cushing's syndrome. Since pergolide mesylate has been removed from the market, the tablets are no longer available. Therefore, pergolide mesylate preparations have to be compounded for veterinary use. Compounded oral liquid formulations have been given arbitrary beyond-use dates of 14 days (aqueous) to 90 days (oil based). The goal of this study was to determine the stability of a 0.2 mg/mL pergolide oral liquid prepared according to a previousy published formulation and stored at room temperature. The sample preparation and ...
Dumasia MC.The in vivo phase I biotransformation of 17 alpha-methyltestosterone in the horse leads to the formation of a complex mixture of regio- and stereoisomeric C(20)O(2), C(20)O(3) and C(20)O(4) metabolites, excreted in urine as glucuronide and sulphate phase II conjugates. The major pathways of in vivo metabolism are the reduction of the A-ring (di- and tetrahydro), epimerisation at C-17 and oxidations mainly at C-6 and C-16. Some phase I metabolites have been identified previously by positive ion electron ionisation capillary gas chromatography/mass spectrometry (GC/EI + MS) mainly from the chara...
Van Eenoo P, Delbeke FT, Deprez P.Clenbuterol, a beta-adrenergic agonist, is used in the treatment of recurrent airway obstruction in horses. It is prohibited by horse racing authorities, because of its stimulating and growth-promoting properties. However, information on detection times of clenbuterol after administration by nebulization is lacking. In this study, a fast, sensitive quantitative GC-MS(2) method for the detection of clenbuterol in urine was developed. Alkaline liquid-liquid extraction was followed by derivatization to a cyclic methyl boronate derivative and analysis on a Finnigan MAT GCQ instrument. Method valid...
Wenzel R, Major D, Hesp K, Doble P.Regulating authorities in the racing industry have restricted the administration of potentially performance enhancing cobalt salts to horses. There are severe penalties for trainers presenting horses with elevated urine cobalt concentrations, and compliance is ensured via analysis of total urinary cobalt at thresholds of 100 μg/L. When cobalt is present as part of the cobalamin molecule it is not considered performance enhancing. This paper demonstrates that a horse can excrete a significant proportion of a commercially available vitamin B12 injection in urine without metabolic modification...
Salonen JS, Vuorilehto L, Gilbert M, Maylin GA.Horse urine was investigated for metabolites by chromatography and mass spectrometry following the oral administration of the large animal analgesic sedative detomidine to two stallions and intravenous administration of [3H]-detomidine to a mare. Detomidine carboxylic acid and hydroxydetomidine glucuronic acid conjugate were identified in the urine after the oral doses. In addition, traces of free hydroxydetomidine were observed. About half of the radioactivity of [3H]-detomidine was excreted in the urine in 12 h after the i.v. dose (80 micrograms/kg). Most of the excretion occurred between 5 ...
Anfossi P, Villa R, Montesissa C, Carli S.Lysine salts are often used in human pharmaceuticals to increase the solubility and absorption of acidic drugs when these are administered parenterally. In this study the intramuscular bioavailability of ketoprofen administered as the lysine salt was evaluated in horses (n = 5) treated intravenously and intramuscularly (2.2 mg/kg active substance) in a cross-over study. The absorption rate of ketoprofen administered as the lysine salt was rather low: the mean residence time increased from 31.7 min after IV injection to 128.9 min (after IM injection), and the bioavailability was high (mean 92.4...
Vonaparti A, Lyris E, Panderi I, Koupparis M, Georgakopoulos C.In equine sport, salicylic acid is prohibited with a threshold level of 750 microg mL(-1) in urine; hence, doping control laboratories have to establish quantitative and qualitative methods for its determination. A simple and rapid liquid chromatographic/mass spectrometric method was developed and validated for the quantification and identification of salicylic acid. Urine samples after 900-fold dilution and addition of the internal standard (4-methylsalicylic acid) were directly injected to the liquid chromatography/quadrupole time-of-flight mass spectrometry system. Electrospray ionization i...
Dyke TM, Sams RA, Hinchcliff KW.To measure renal clearance of antipyrine and urinary excretion of antipyrine (AP) metabolites in horses by use of validated high-performance liquid chromatography (HPLC) methods. Methods: 8 Standardbred mares. Methods: HPLC methods for measurement of AP in equine plasma and AP and its metabolites in equine urine were validated. Antipyrine (20 mg/kg of body weight) was administered i.v., and blood samples and urine specimens were collected over 24 hours. Results: Median plasma clearance of AP in horses was 6.2 ml/min/kg, of which < 2% could be attributed to renal clearance. Urinary excretion...
Stewart RH, Griffiths JP.In spinal cord disease of horses, a complete history, neurologic examination, and adjunctive diagnostic procedures are very helpful in establishing a tentative diagnosis; however, a definitive diagnosis may be difficult or impossible to establish antemortem. Medical management should be initiated with full consideration of possible etiologies and knowledge of the effects and consequences of medical therapies. This article discusses the drugs commonly used in the management of spinal cord disease and the rationale for their use.
Costello S, Heffron B, Taddei L, Benoit M, Hurt L, Simpson L, Bishop J, Folker-Calderon D, Negrusz A.Fluphenazine, a potent antipsychotic used to treat schizophrenia in humans, is used in racehorses as a performance-enhancing drug, and for that reason it has been banned by the Association of Racing Commissioners International. A liquid chromatography-tandem mass spectrometry method for detecting and quantitating fluphenazine in equine serum was developed and validated. The method was then employed to quantitate fluphenazine in serum samples collected from three study horses after intramuscular injection of fluphenazine decanoate. Stability testing showed that fluphenazine is stable in unextra...
Aramaki S, Ishidaka O, Suzuki E, Momose A, Umemura K.In a doping test for racing horses, it is useful for the elucidation of the illegal use of drugs if one can estimate the time at which the detected drug was administered. In order to estimate the time which has elapsed after the administration of caffeine (CA) into horses, the ratios of concentration for the respective metabolites to the unchanged CA in the plasma or the urine were determined. These ratios have been known to be independent of the dose of CA. The relationship between [plasma or urinary concentration of a metabolite]/ [plasma or urinary concentration of the unchanged drug] and t...
Karatt TK, Muhammed Ajeebsanu M, Karakka Kal AK, Subhahar MB, Sathiq MA, Laya S.The formation of mass adducts is common during electrospray ionization mass spectrometry (ESI-MS). However, the mechanism that leads to adduct formation is poorly understood and difficult to control. Multiplication of mass adducts at once will adversely impact the sensitivity of mass analysis and cause misinterpretation of the level of detection. Prior studies on selective androgen receptor modulators (SARMs) revealed an immense mass adduct formation in both positive and negative ESI modes. Methods: In this study, additives in the mobile phases are investigated as a potential means of controll...
Assis RA, Kuchler IL, Miekeley N, Tozzi MB.Capillary electrophoresis coupled to inductively coupled plasma mass spectrometry was used in a speciation study on disodium monomethylarsonate (DS-MMA(V)) and its metabolites in horses, to which the drug was administered by intramuscular injection on five consecutive days at a single arsenic dosage of 270 mg day(-1). Samples of urine, whole blood, plasma, and mane hair were analyzed before, during, and after drug administration. The data show that blood clearing and urinary excretion of MMA is a fast process following first-order kinetics with biological half-lives of about 38 h and 44 h for ...
Emmerich IU.In 2015, four newly developed active pharmaceutical ingredients for horses and food-producing animals were released on the German market for veterinary drug products. These were the bisphosphonate Clodronic Acid (Osphos®), the 5-hydroxytryptamine (2A) receptor antagonist Ketanserin (Vulketan®), the aminoglycoside antibiotic Paromomycin (Parofor®) and the antibiotic Thiamphenicol (TAF Spray®) from the fenicole group. With Chlorphenamine, a temporary not available active ingredient was reapproved in a new drug. Furthermore, three veterinary drugs with a new formulation as well as one product...
You Y, Uboh CE, Soma LR, Guan F, Li X, Rudy JA, Chen J.A sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated for screening, quantification, and confirmation of phenylbutazone and oxyphenbutazone in equine plasma. Analytes were recovered from plasma by liquid-liquid extraction followed by separation in a reversed-phase column and identification by mass spectrometry with selected reaction monitoring in negative electrospray ionization mode. Extraction recovery for both analytes was >80%. Limits of detection, quantification, and confirmation for both analytes were 0.01 microg/mL (S/N>or= 3), 0.05 microg...
Van Eenoo P, Deventer K, Delbeke FT.A sensitive, accurate and precise liquid chromatography/tandem mass spectrometry (LC/MS(2)) method was developed for the quantification of salmeterol in the urine of horses. The method consists of a liquid-liquid extraction with tert-butylmethyl ether and isopropanol at pH 12 after enzymatic hydrolysis. The extracts are analysed using an LC/MS system equipped with an electrospray ionisation (ESI) probe. Method validation showed excellent linearity, specificity, accuracy, precision and intra-laboratory repeatability and reproducibility. The limit of quantitative detection was 0.25 ng/mL and the...
Beaudry F, Lavoie JP, Vachon P.A rapid and selective method has been developed for the determination of theophylline in horse serum by LC-ESI/MS/MS. The analytical method includes a protein precipitation extraction for sample preparation, liquid chromatography separation technique and ionspray tandem mass spectrometry. The drug was extracted from serum using a protein precipitation with acetonitrile and the supernatants were analyzed using an LC-ESI/MS/MS instrument. The chromatography was performed using a 50 x 2.1 mm C(8) analytical column and an isocratic mobile phase composes of 60:40 acetonitrile-0.5% formic acid in wa...
Müntener CR, Müntener C, Kupper J, Naegeli H, Gassner B.A total of 253 reports of adverse reactions to veterinary medicinal products were received during the year 2016 representing a decrease of 13% compared to the previous year (292 reports). The majority of the reports described reactions affecting companion animals (178 dogs and 32 cats) as well as cattle (17 reports) and horses (10 reports). Most of the reactions reported were linked to the use of antiparasitics (145 reports), hormone products (26 reports) and antiinfectives (10 reports). 32 reports were generated from consultations with Tox Info Suisse in Zürich and involved mainly the excess...
Singh AK, Ashraf M, Granley K, Mishra U, Rao MM, Gordon B.A simple and reproducible column (Clean Screen-DAU, copolymeric bonded-phase silica column) extraction procedure has been described for the screening and confirmation of drugs in horse urine. The recovery of drugs by the column extraction was better than or comparable to the recovery by the liquid-liquid extraction, which is commonly used in the equine analytical laboratories. The column extraction provided broad coverage of drugs, separated extracts into three fractions (acidic/neutral, steroids, basic), produced a cleaner extract, and eliminated the need for special liquid-liquid extraction ...
Dehennin L, Bonnaire Y, Plou P.The dietary supplements 19-norandrostenedione and 19-norandrostenediol are potential metabolic precursors of nandrolone. They are considered by law in the United States as prohormones without proven therapeutic, curative or diagnostic properties, and therefore available as over-the-counter drugs. Oral dosages of 0.1-1 mg/kg body weight were readily absorbed in the equine intestinal tract and thereby led to urinary excretion of drastically increased 5alpha-estrane-3beta,17alpha-diol conjugates, which are known to be final metabolites of nandrolone. The actual rules for detection of illicit nand...
Knych HK, Stanley SD, Arthur RM, McKemie DS.Cetirizine is an antihistamine used in performance horses for the treatment of hypersensitivity reactions and as such a withdrawal time is necessary prior to competition. The objective of the current study was to describe the disposition and elimination of cetirizine following oral administration in order to provide additional serum concentration data upon which appropriate regulatory recommendations can be established. Nine exercised thoroughbred horses were administered 0.4 mg/kg of cetirizine orally BID for a total of five doses. Blood samples were collected immediately prior to drug admin...
Emmerich IU.In 2022, one novel pharmaceutical agent was released on the German market for horses or food-producing animals: An injection suspension for horses containing tenogenic primed equine allogeneic peripheral blood-derived mesenchymal stem cells as the active ingredient (RenuTend®) is now available. The authorization of one established veterinary active ingredient was extended to an additional species: The synthetic prostaglandin F2α-analogue cloprostenol (Syncroprost®) received approval for goats. Additionally, for 2 active ingredients (paracetamol, suxibuzone), drugs with a higher content of t...
Wong JKY, Kwok WH, Chan GHM, Choi TLS, Ho ENM, Jaubert M, Bailly-Chouriberry L, Bonnaire Y, Cawley A, Ming Williams H, Keledjian J, Brooks L....Acadesine, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, commonly known as AICAR, is a naturally occurring adenosine monophosphate-activated protein kinase (AMPK) activator in many mammals, including humans and horses. AICAR has attracted considerable attention recently in the field of doping control because of a study showing the enhancement of endurance performance in unexercised or untrained mice, resulting in the term 'exercise pill'. Its use has been classified as gene doping by the World Anti-Doping Agency (WADA), and since it is endogenous, it may only be possible to control del...
Skrabalak DS, Henion JD.Betamethasone and its major unconjugated metabolite, 6-beta-hydroxybetamethasone, were detected in equine urine by thin-layer chromatography and characterized by micro-liquid chromatography/mass spectrometry (micro-LC/MS). Their structures were confirmed by a combination of infrared spectroscopy and nuclear magnetic resonance spectroscopy.
Wallace GE, McKaba VF, Reinhart JM, Li Z, Austin S, Fries RC.Large vessel and microvascular thrombi are common complications in systemically ill horses contributing to patient morbidity and mortality. Apixaban, an oral factor Xa inhibitor, shows excellent efficacy against stroke and deep vein thrombosis in humans. The purpose of this study was to determine serum apixaban concentrations and anti-factor Xa activity in horses after orally administered apixaban. Five horses received a single dose of intravenous (0.09 mg/kg) and oral (1 mg/kg) apixaban in a cross-over design. Serum apixaban concentrations and anti-Xa activity were measured serially via liq...
Takeda A, Shinohara T.A simple method for the simultaneous analysis of tiaramide (TRA) metabolites in the horse is described. The sample preparation method using a Bond-Elut PH cartridge and stepwise elution with ice-cold, 30% aqueous methanol followed by additional methanol is effective for recovering the metabolites with different properties. The extraction method gives good recoveries (greater than 80%) and reproducibility. Each metabolite is well separated by high-performance liquid chromatography using an octadecyl-type column of polymer-based packing with a solvent system of 20 mM phosphate buffer (pH 6.5)-ac...
Houghton E, Teale P, Dumasia MC, Wellby JK.The negative ion chemical ionization mass spectra of the MO-TMS derivatives of the corticosteroids prednisolone, betamethasone and dexamethasone have been obtained using capillary column gas chromatography mass spectrometry. The spectra showed abundant diagnostic ions at m/z greater than 300 allowing for clear discrimination between the three steroid derivatives. A capillary column gas chromatographic mass spectrometric method using negative ion chemical ionization mass spectrometry has been developed to confirm the presence of the parent steroids in horse urine following the administration of...
