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.
Dixon PM.The structure and possible functions of respiratory secretions are reviewed. In the equine, goblet (mucus producing) cells are the main source but little information is available on the volume or composition of equine respiratory secretions. Airway mucus has complex and incompletely understood physical characteristics which can be partially assessed by a wide range of in vitro and biological techniques. The complex relationship between mucus structure and its propulsion by the airway cilia are discussed, both in health and with pulmonary disease. Mucokinesis in the horse has been assessed visu...
Hagedorn HW, Schulz R, Friedrich A.The metabolic transformation of methandienone (I) in the horse was investigated. After administration of a commercial drug preparation to a female horse (0.5 mg/kg), urine samples were collected up to 96 h and processed without enzymic hydrolysis. Extraction was performed by a series of solid-liquid and liquid-liquid extractions, thus avoiding laborious purification techniques. For analysis by gas chromatography-mass spectrometry, the extracts were trimethylsilylated. Besides the parent compound I and its C-17 epimer II, three monohydroxylated metabolites were identified: 6 beta-hydroxymethand...
Steffenrud S, Maylin G.A high-performance liquid chromatographic method was developed for thermospray mass spectrometric analysis of steroidal hormones. Using a Nova-Pak C18 reversed-phase column and isocratic elution with a solvent comprised of 25 mM ammonium formate in 30% acetonitrile, corticosteroids were separated within 10 min. This solvent also permitted ultraviolet absorbance detection down to 220 nm with low-nanogram sensitivity. The use of acetonitrile was favourable for thermospray mass spectrometric analysis because mass spectra were obtained with a pseudomolecular ion as the base peak. A combination of ...
Coyne CP, Smith JE, DeBowes RM.Several pharmaceutical compounds were evaluated for their ability to selectively inhibit activated coagulation factor-XIII-like enzyme activity (eg, XIIIa*) in pooled equine plasma. Presence of coagulation factor-XIIIa*-like enzyme activity in plasma was established by assay procedures involving incorporation of the fluorescent amine compound, monodansylcadaverine, into purified casein, which served as a protein substrate. Pharmaceuticals inhibitory to coagulation factor-XIIIa*-like enzyme activity were recognized by plasma gel formation of high spectrophotometric transmittance (transparency),...
Hagedorn HW, Schulz R.The use of diuretics in horses subject to doping control is prohibited. Thus, a sensitive screening procedure is required to identify the chemically different diuretics. We communicate here a method to detect three commonly employed acidic diuretics: bumetanide, ethacrynic acid, and furosemide. A liquid-liquid extraction on Extrelut 3 was performed at weak acidic and basic conditions using ethyl acetate as organic solvent. For analysis by GC, the diuretics were methylated on-column in the presence of MSTFA/TMAH, avoiding the commonly employed highly toxic derivatizing agent methyl iodide. For ...
Stevenson AJ, Weber MP, Todi F, Mendonca M, Fenwick JD, Young L, Kwong E, Chen F, Beaumier P, Timmings S.The variability in plasma and urine equine procaine measurement between three independent laboratories using current methods led to the development of a sensitive, reliable, and reproducible high-performance liquid chromatographic method. Standardbred mares were administered either a penicillin G procaine preparation intramuscularly or procaine hydrochloride subcutaneously, and blood and urine were collected at defined time intervals. By HPLC the detection limits for procaine in plasma and urine were 1 and 10 ng/mL, respectively. In contrast procaine in plasma could not be detected by GC-NPD, ...
Zertuche JM, Brown MP, Gronwall R, Merritt K.Pharmacokinetic values for flunixin meglumine (1 mg/kg of body weight) and phenylbutazone (4 mg/kg) dosages were determined after a single IV injection with and without concurrent intragastric administration of probenecid (50 mg/kg) in 6 healthy mares. Significant difference was not apparent in the pharmacokinetic values of flunixin meglumine with and without concurrent probenecid administration. Significant (P less than or equal to 0.05) increase was evident in the 12-hour mean concentration of phenylbutazone (11.45 +/- 1.66 micrograms/ml without probenecid; 14.56 +/- 1.20 micrograms/ml with ...
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, Detra RL, Muir WW.The pharmacokinetics and metabolism of doxapram in horses administered intravenous (iv) doses of 0.275, 0.55 and 1.1 mg doxapram/kg bodyweight (bwt) were investigated. Plasma doxapram concentrations decreased rapidly after drug administration and the disappearance of doxapram from plasma was best described by a polyexponential equation. Median values of total body clearance were 10.9, 10.6 and 10.9 ml/min/kg bwt for the three doses and were independent of dose. The steady-state volume of distribution was approximately 1,200 ml/kg bwt and the median biological half-life ranged from 121 to 178 m...
Jaussaud P, Guieu D, Courtot D, Barbier B, Bonnaire Y.A tolfenamic acid metabolite, a hydroxylated product, has been identified in equine plasma and urine samples using gas chromatography-mass spectrometry in the electron-impact and chemical-ionization modes. The method also allows the qualitative monitoring of the elimination of the drug and its metabolites from plasma. The two compounds are detected up to 48 and 24 h, respectively, after a single oral administration of a 30 mg/kg dose. The simultaneous detection of the two products increases the reliability of anti-doping control analysis.
Matassa LC, Woodard D, Leavitt RK, Firby P, Beaumier P.Glycopyrrolate (Robinul) is a quaternary ammonium salt which serves as a respiratory enhancing drug. It is reportedly used in horse racing to improve breathing. Extraction of glycopyrrolate from equine urine employing unique solid-phase extraction techniques gave a residue suitable for liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-mass spectrometry (GC-MS). LC-MS-MS analysis employed an extract derived from 5 ml of urine subjected to cation-exchange chromatography. The daughter ion of m/z 318 monitored in the positive-ion mode was m/z 116. Recovery of glycopy...
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 ...
Stanley S, Jeganathan A, Wood T, Henry P, Turner S, Woods WE, Green M, Tai HH, Watt D, Blake J.We have raised antibodies to morphine and etorphine and developed one-step enzyme-linked immunosorbent assays (ELISA) for these drugs as part of a panel of post race tests for drugs in racing horses. These tests are simple, can be completed in 2 h, and can be read by visual inspection. The morphine ELISA has an I50 for morphine of about 1.5 ng/mL, while the etorphine ELISA has an I50 for etorphine of 250 pg/mL. Cross-reactivity studies show that the antimorphine antibody cross-reacts well with levorphanol, hydromorphone, and oxycodone, while the anti-etorphine antibody showed no cross-reactivi...
Heinrich B.This research article corrects a common misconception about the energy metabolism in horses during short sprinting and long-distance running events, emphasizing that short sprints are primarily powered by anaerobic activity, […]
Chapman CB, Courage P, Huntington PJ.A high-performance liquid chromatography (HPLC) assay was developed for the detection of reserpine. The assay was used to monitor the plasma concentrations of the drug given intramuscularly on one or two occasions to five horses. The blood concentrations of reserpine varied quite considerably between horses given the same dose of the drug. However, on average, reserpine could be detected consistently, and quantified, for 48 h after a single dose of 2.5 mg, and for a similar period after the second of two 2.5 mg doses given 13 d apart. Because of the apparently large variability in the pharmaco...
Prügner W, Huber R, Lühmann R.Two controlled studies to determine efficacy in the horse were performed with eltenac, a new injectable, non-steroidal anti-inflammatory drug (NSAID). Clinical trials were carried out with a dose rate of 1 mg/kg body weight in a randomized, placebo-controlled, double-blind design to assess therapeutic efficacy in acute inflammatory disorders and in animals with orthopaedic conditions. In a preliminary pharmacokinetic investigation in six horses mean elimination half-life was 1.7 h after i.v. administration. In the first clinical study, analgesic activity on pain-related lameness was determined...
Delbeke FT, Debackere M, Vynckier L.A high-performance liquid chromatographic method to measure urinary indomethacin levels is described. In 0.5 ml urine, 1 micrograms/ml of indomethacin could be detected. Alkaline hydrolysis of urine resulted in the decomposition of indomethacin. When two suppositories of Indocid corresponding to 200 mg indomethacin were administered rectally to four horses the drug was rapidly absorbed and remained detectable in urine from 1 to 12 h. The excretion rate peaked after 2-3 h while the maximal concentration ranged from 18.5 to 80.6 micrograms/ml. Only 8 to 16% of the indomethacin dose was eliminate...
Pereira MC, Kohek Júnior I, Campos R, Lima SB, Foz RP.The anthelmintic efficacy of ivermectin (IVM), piperazine citrate (PPZ) and fenbendazole (FBZ) alone, and combinations of FBZ with varying dosages of PPZ, was evaluated for the control of strongyles of Mangalarga equids. In all cases of positive strongly egg counts per gram of faeces (EPG) before and after treatment, pure populations of cyathostome larvae with eight gut cells were consistently observed in faecal cultures. The faecal egg count reductions (FECR) were evaluated between Day 7 and Day 56 post-treatment. Significant differences (P less than or equal to 0.05) were found between Day 7...
Bourdon R.Toxicomania and doping give rise to an increasing number of drug measurements in the body fluids. Consequently the analysts have to face, at one and the same time, ethical and analytical problems. Should the analyst participate to investigations organised in order to disclose a toxicomania in a working place? The author suggests a positive answer as long as the adduct person benefits to a social and medical care. What is the analytical meaning of a positive test? Taking into account the increasing sensitivity of the methods used, thresholds have to be established, at least for the blood concen...
Uboh CE, Rudy JA, Soma LR, Fennell M, May L, Sams R, Railing FA, Shellenberger J, Kahler M.The purpose of this study was two-fold: (1) to develop a simple and sensitive screening procedure for identifying and confirming bromhexine and ambroxol and, (2) to determine the effect of furosemide on the detection of bromhexine, ambroxol, or their metabolites in urine. Female horses (450-550 kg) treated with bromhexine or ambroxol (1 g, p.o.) were used. Urine samples were collected up to 48 h post-drug administration and analysed. Blind samples were used in evaluating the sensitivity of these methods and reproducibility of the results. Bromhexine and ambroxol were extensively metabolized in...
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.
Guan F, You Y, Fay S, Adreance MA, McGoldrick LK, Robinson MA.Doping control is essential for sports, and untargeted detection of doping agents (UDDA) is the holy grail for anti-doping strategies. The present study examined major factors impacting UDDA with metabolomic data processing, including the use of blank samples, signal-to-noise ratio thresholds, and the minimum chromatographic peak intensity. Contrary to data processing in metabolomics studies, both blank sample use (either blank solvent or plasma) and marking of background compounds were found to be unnecessary for UDDA in biological samples, the first such report to the authors' knowledge. The...
Wijnberg ID, van der Kolk JH, Hiddink EG.Two miniature Shetland ponies showing clinical signs of Digitalis purpurea (foxglove) poisoning were examined. One animal died shortly afterwards, but the second was treated successfully with the anti-arrhythmic agent, phenytoin, and was discharged after 16 days.
Respondek F, Lallemand A, Julliand V, Bonnaire Y.Presence of drugs is completely prohibited in post racing urine samples by most of racing and competition authorities, even if environmental contamination might occur. Objective: To assess the daily dose of several contaminants absorbed through the diet that would result in detectable concentrations in urine. Methods: Caffeine, theobromine, theophylline, atropine, scopolamine, bufotenine, DMT or morphine were administered orally to 6 horses, in different dosages, for 3 days before their urine was sampled for regular anti-doping tests. Results: Theobromine, theophylline, bufotenine and morphine...
Salvadori MC, Rieser EM, Ribeiro Neto LM, Nascimento ES.The seeds of Guaraná are rich in xanthines and are used for the preparation of guaraná powder which is very commonly given to horses as a 'tonic' in Brazil. In this paper, the xanthine content of guaraná powder was determined, in addition to its clearance time in horses. Thin-layer chromatography was used as a screening procedure and high-performance liquid chromatography was performed to quantify the drugs in both the powder and urine samples. The guaraná powder was found to contain 2.16, 1.10 and 36.78 mg g-1 of theobromine (TB), theophylline (TP) and caffeine (CF), respectively, and in ...
Maddison JE.Seventy-seven reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee (ADRSc) of the Australian Veterinary Association from April 1993 to December 1994 inclusive. The number of reports received/number of animals involved per species were: dogs (32/44), cats (18/31), horses (17/48), and cattle (10/21). Of these, 49 (64%) were classified as definite ADRs and 9 (12%) as probable ADRs. In 11 (14%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Eight reports were not classified because ...
Park J, Shin YO, Choo HY.The propionylpromazine concentrations in plasma after intramuscular administration to horses were determined using gas chromatography with nitrogen-phosphorus detection. After hydrolysis by beta-glucuronidase/arylsulphatase, the parent drug and three metabolites were detected in urine. The metabolites were identified as 2-(1-hydroxypropyl)promazine, 2-(1-propenyl)promazine and 7-hydroxypropionylpromazine by gas chromatography-mass spectrometry. No N-demethylated or sulphoxidated metabolites of propionylpromazine were observed in the horse urine.
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Muir T, Biddle S, Van Eenoo P.AC-262536 is one of a number of selective androgen receptor modulators that are being developed by the pharmaceutical industry for treatment of a range of clinical conditions including androgen replacement therapy. Though not available therapeutically, selective androgen receptor modulators are widely available to purchase online as (illegal) supplement products. The growth- and bone-promoting effects, along with fewer associated negative side effects compared with anabolic-androgenic steroids, make these compounds a significant threat with regard to doping control in sport. The aim of this st...
Clarke EG, Moss MS.Doping can improve or impair performance and can be done either deliberately or accidentally. Accidental doping to win is the offence which most concerns the veterinary surgeon. The distinction between legitimate therapy and assisting an unfit horse to win a race by giving it a drug is a fine one. General guidelines are presented for the veterinary surgeon in practice.
Kauffman VG, Soma L, Divers TJ, Perkons SZ.To provide long-term sedation, a horse was given fluphenazine decanoate, a human antipsychotic drug. The horse was progressively agitated and made unusual repetitive motions. Sedation with barbiturates was an effective treatment. This case is not unusual, and the use of fluphenazine by veterinarians in horses as a mild long-acting tranquilizer is not uncommon.