Analyze Diet

Topic:Pharmaceuticals

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.
Investigation of in vitro generated metabolites of GLPG0492 using equine liver microsomes for doping control.
Drug testing and analysis    February 19, 2023   Volume 15, Issue 6 605-628 doi: 10.1002/dta.3453
Karatt TK, Sathiq MA, Laya S, Philip M, Karakka Kal AK, Subhahar MB.An effective alternative to testosterone therapy is selective androgen receptor modulators, a class of compounds that has a tissue-specific effect on muscle and bone. These drugs, which enhance performance, pose a severe abuse risk in competitive sports. GLPG0492 is one of the selective androgen receptor modulators discovered in recent decades. This compound has a unique tissue-specific action for muscle and bone against steroid receptors and acts as a partial agonist for androgen receptors. This study examined GLPG0492 and its metabolites in vitro using equine liver microsomes. Liquid chromat...
Use of Liquid Chromatography–Tandem Mass Spectrometry to Quantify and Confirm the Fentanyl Metabolite N-[1-(2-Phenethy-4-Piperidinyl)] Maloanilinic Acid in Equine Urine for Doping Control.
Journal of analytical toxicology    February 11, 2023   Volume 47, Issue 4 393-402 doi: 10.1093/jat/bkad008
You Y, Proctor RM, Haughan J, Missanelli JR, Robinson MA.Fentanyl, a powerful synthetic mu opioid receptor agonist, is banned in equine sports by the Association of Racing Commissioners International and the Fédération Équestre Internationale. The presence of fentanyl in equine blood has been confirmed during routine post-race screening for doping substances in the authors' laboratory. While fentanyl can be detected and confirmed in blood, it is rapidly metabolized, and screening for the metabolite N-[1-(2-phenethy-4-piperidinyl)] maloanilinic acid (PMA) in equine urine is expected to allow for a longer detection time. In this study, a quantitati...
Metabolic study of selective androgen receptor modulator LY2452473 in thoroughbred horses for doping control.
Rapid communications in mass spectrometry : RCM    February 10, 2023   Volume 37, Issue 9 e9491 doi: 10.1002/rcm.9491
Karatt TK, Sathiq MA, Laya S, Karakka Kal AK, Subhahar MB, M P MA, Philip M, Graiban FM, Caveney MR.Since 2010, there has been an increasing number of adverse analytical findings related to selective androgen receptor modulators (SARMs) in competitive sports. It emphasizes the importance of comprehensive doping control analytical procedures that are capable of detecting SARM misuse. Methods: In this study, it is described how LY2452473, a SARM, was metabolized in thoroughbred horses after a single-dose oral administration and in vitro with equine liver microsome preparations. An investigation of the metabolism of LY2452473 in horses' urine, plasma, and hair matrices was carried out during th...
Equine metabolism of the selective androgen receptor modulator YK-11 in urine and plasma following oral administration.
Drug testing and analysis    January 4, 2023   Volume 15, Issue 4 388-407 doi: 10.1002/dta.3425
Harding C, Viljanto M, Habershon-Butcher J, Taylor P, Scarth J.YK-11 is a steroidal selective androgen receptor modulator, a compound class prohibited in both equine racing and human sports because of their potentially performance enhancing properties. YK-11 is easily accessible via internet-based supplement vendors making this compound a possible candidate for doping; however, its phases I and II metabolism has not yet been reported in the horse. The purpose of this study was to investigate the in vivo metabolites of YK-11 in urine and plasma following oral administration with three daily doses of 50 mg to two Thoroughbred horses. In vitro incubations ...
Towards Non-Targeted Screening of Lipid Biomarkers for Improved Equine Anti-Doping.
Molecules (Basel, Switzerland)    December 30, 2022   Volume 28, Issue 1 312 doi: 10.3390/molecules28010312
Tou K, Cawley A, Bowen C, Bishop DP, Fu S.The current approach to equine anti-doping is focused on the targeted detection of prohibited substances. However, as new substances are rapidly being developed, the need for complimentary methods for monitoring is crucial to ensure the integrity of the racing industry is upheld. Lipidomics is a growing field involved in the characterisation of lipids, their function and metabolism in a biological system. Different lipids have various biological effects throughout the equine system including platelet aggregation and inflammation. A certain class of lipids that are being reviewed are the eicosa...
Changes in Heart Rate Variability with Induction of Gastric Ulcers in Adult Horses.
Journal of equine veterinary science    December 11, 2022   Volume 121 104192 doi: 10.1016/j.jevs.2022.104192
Louie EW, Berryhill EH, Nieto J, Wensley F, Knych H, Finno CJ, Morgan JM.Gastric ulceration can be induced by athletic training and is a significant welfare concern. The objective of this study was to evaluate the effect of gastric ulcer induction on heart rate variability (HRV) in the horse. We hypothesized that induction of gastric ulcers would decrease HRV and increase low frequency fluctuations, consistent with increased sympathetic tone. A convenience sample of 8 horses in a larger study were enrolled. Horses were randomly assigned to receive water or 2 mg/kg omeprazole orally once daily for 28 days. Gastric ulcers were induced through intermittent feed withho...
Cocktail drug usage and etofenamate detection in post-race equine urine sample: A case report.
Biomedical chromatography : BMC    December 10, 2022   Volume 37, Issue 3 e5556 doi: 10.1002/bmc.5556
Kabil E, Göktaş EF, Güneş E, Yatanaslan L, Zor TA, Tektaş MH, İnceman B, Tufan M.A recent trend in the use of high-resolution accurate mass screening (HRAMS) for doping control testing in both human and animal sports has emerged owing to significant improvement in high-resolution mass spectrometry in terms of sensitivity, mass accuracy, mass resolution and mass stability. Several HRAMS methods have been reported for the detection of multidrug residues in human or equine urine. These improved analytical technologies have led to changes in the use of prohibited substances, and the administration of more than one substance at low concentrations as a "cocktail" has become one ...
DrugCentral 2023 extends human clinical data and integrates veterinary drugs.
Nucleic acids research    December 10, 2022   Volume 51, Issue D1 D1276-D1287 doi: 10.1093/nar/gkac1085
DrugCentral monitors new drug approvals and standardizes drug information. The current update contains 285 drugs (131 for human use). New additions include: (i) the integration of veterinary drugs (154 for animal use only), (ii) the addition of 66 documented off-label uses and iii) the identification of adverse drug events from pharmacovigilance data for pediatric and geriatric patients. Additional enhancements include chemical substructure searching using SMILES and 'Target Cards' based on UniProt accession codes. Statistics of interests include the following: (i) 60% of the covered drugs are...
Enantioselective CE-MS analysis of ketamine metabolites in urine.
Electrophoresis    December 9, 2022   Volume 44, Issue 1-2 125-134 doi: 10.1002/elps.202200175
Sandbaumhüter FA, Aerts JT, Theurillat R, Andrén PE, Thormann W, Jansson ET.The chiral drug ketamine has long-lasting antidepressant effects with a fast onset and is also suitable to treat patients with therapy-resistant depression. The metabolite hydroxynorketamine (HNK) plays an important role in the antidepressant mechanism of action. Hydroxylation at the cyclohexanone ring occurs at positions 4, 5, and 6 and produces a total of 12 stereoisomers. Among those, the four 6HNK stereoisomers have the strongest antidepressant effects. Capillary electrophoresis with highly sulfated γ-cyclodextrin (CD) as a chiral selector in combination with mass spectrometry (MS) was us...
Agmatine Administration Effects on Equine Gastric Ulceration and Lameness.
Journal of clinical medicine    December 8, 2022   Volume 11, Issue 24 doi: 10.3390/jcm11247283
Taguchi T, Morales Yniguez FJ, Takawira C, Andrews FM, Lopez MJ.Osteoarthritis (OA) accounts for up to 60% of equine lameness. Agmatine, a decarboxylated arginine, may be a viable option for OA management, based on reports of its analgesic properties. Six adult thoroughbred horses, with lameness attributable to thoracic limb OA, received either daily oral phenylbutazone (6.6 mg/kg), agmatine sulfate (25 mg/kg) or a control for 30 days, with 21-day washout periods between treatments. Subjective lameness, thoracic limb ground reaction forces (GRF), plasma agmatine and agmatine metabolite levels were evaluated using an established rubric, a force platform, an...
Equine endoparasite resistance and its management – a vet practice perspective.
The Veterinary record    December 3, 2022   Volume 191, Issue 11 e2512 doi: 10.1002/vetr.2512
Wallace J.With concerns growing globally about anthelmintic resistance in equine endoparasites, James Wallace's practice undertook some research among its horse-owning clients and introduced a fixed-fee parasite management programme to help ensure the most effective use of these valuable medicines.
Hydroxy levamisole and its phase II conjugates as potential indicators of levamisole doping in thoroughbred horses.
Rapid communications in mass spectrometry : RCM    November 17, 2022   Volume 37, Issue 3 e9430 doi: 10.1002/rcm.9430
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Perwad Z, Graiban FM, Caveney MR, Sayed R, Kadry AM.According to previous research, aminorex is the major metabolite of levamisole; however, in the screening of levamisole-positive racehorse urine and plasma samples, aminorex could only be detected in trace amounts or not at all. In forensic laboratories, hydroxy levamisole and its phase II conjugates make it easier to confirm levamisole misuse and to differentiate between the abuse of levamisole and aminorex. This study aimed to identify the major levamisole metabolites that can be detected along with the parent drug. Methods: The study describes levamisole and its metabolites in thoroughbred ...
Safety and efficacy of a feed additive consisting of glyceryl polyethyleneglycol ricinoleate (PEG castor oil) for all animal species (FEFANA asbl).
EFSA journal. European Food Safety Authority    October 28, 2022   Volume 20, Issue 10 e07433 doi: 10.2903/j.efsa.2022.7433
Bampidis V, Azimonti G, Bastos ML, Christensen H, Dusemund B, Fašmon Durjava M, Kouba M, López-Alonso M, López Puente S, Marcon F, Mayo B....Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of glyceryl polyethyleneglycol ricinoleate (PEG castor oil) as technological feed additive for all animal species. PEG castor oil is safe at a maximum concentration in complete feed of 90 mg/kg for chickens for fattening and other minor growing poultry; 134 mg/kg for laying hens and other laying/breeding birds kept for egg production/reproduction; 121 mg/kg for turkeys for fattening; 162 mg/kg for piglets and other minor growing ; 194 mg/kg for pigs for fattening; 23...
Shortened egg reappearance periods of equine cyathostomins following ivermectin or moxidectin treatment: morphological and molecular investigation of efficacy and species composition.
International journal for parasitology    October 13, 2022   Volume 52, Issue 12 787-798 doi: 10.1016/j.ijpara.2022.09.003
Nielsen MK, Steuer AE, Anderson HP, Gavriliuc S, Carpenter AB, Redman EM, Gilleard JS, Reinemeyer CR, Poissant J.Macrocyclic lactones have been the most widely used drugs for equine parasite control during the past four decades. Unlike ivermectin, moxidectin exhibits efficacy against encysted cyathostomin larvae, and is reported to have persistent efficacy with substantially longer egg reappearance periods. However, shortened egg reappearance periods have been reported recently for both macrocyclic lactones, and these findings have raised several questions: (i) are egg reappearance period patterns different after ivermectin or moxidectin treatment? (ii) Are shortened egg reappearance periods associated w...
Generic approach for the discovery of drug metabolites in horses based on data-dependent acquisition by liquid chromatography high-resolution mass spectrometry and its applications to pharmacokinetic study of daprodustat.
Analytical and bioanalytical chemistry    October 1, 2022   Volume 414, Issue 28 8125-8142 doi: 10.1007/s00216-022-04347-2
Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN.In drug metabolism studies in horses, non-targeted analysis by means of liquid chromatography coupled with high-resolution mass spectrometry with data-dependent acquisition (DDA) has recently become increasingly popular for rapid identification of potential biomarkers in post-administration biological samples. However, the most commonly encountered problem is the presence of highly abundant interfering components that co-elute with the target substances, especially if the concentrations of these substances are relatively low. In this study, we evaluated the possibility of expanding DDA coverag...
Pharmacokinetic Study of Vadadustat and High-Resolution Mass Spectrometric Characterization of its Novel Metabolites in Equines for the Purpose of Doping Control.
Current drug metabolism    August 27, 2022   Volume 23, Issue 10 850-865 doi: 10.2174/1389200223666220825093945
Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN.Vadadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, is a substance which carries a lifetime ban in both horse racing and equestrian competition. A comprehensive metabolic study of vadadustat in horses has not been previously reported. Objective: Metabolism and elimination profiles of vadadustat in equine plasma and urine were studied for the purpose of doping control. Methods: A nasoesophageal administration of vadadustat (3 g/day for 3 days) was conducted on three thoroughbred mares. Potential metabolites were comprehensively detected by differential analysis of ful...
Efficient and Scalable Process to Produce Novel and Highly Bioactive Purified Cytosolic Crystals from Bacillus thuringiensis.
Microbiology spectrum    August 10, 2022   Volume 10, Issue 4 e0235622 doi: 10.1128/spectrum.02356-22
Chicca J, Cazeault NR, Rus F, Abraham A, Garceau C, Li H, Atwa SM, Flanagan K, Soto ER, Morrison MS, Gazzola D, Hu Y, Liu DR, Nielsen MK, Urban JF....Bacillus thuringiensis (Bt) is a Gram-positive soil bacterium that is widely and safely applied in the environment as an insecticide for combatting insect pests that damage crops or are disease vectors. Dominant active ingredients made by Bt are insect-killing crystal (Cry) proteins released as crystalline inclusions upon bacterial sporulation. Some Bt Cry proteins, e.g., Cry5B (formally Cry5Ba1), target nematodes (roundworms) and show exceptional promise as anthelmintics (cures for parasitic nematode diseases). We have recently described inactivated bacteria with cytosolic crystal(s) (IBaCC) ...
Simultaneous quantification of caffeine and its main metabolites by gas chromatography mass spectrometry in horse urine.
Biomedical chromatography : BMC    July 15, 2022   Volume 36, Issue 10 e5445 doi: 10.1002/bmc.5445
Göktaş EF, Kabil E, Yatanaslan L, Güneş E, Dirikolu L.Caffeine is a naturally occurring alkaloid and it is metabolized to paraxanthine, theophylline and theobromine. Analysis of caffeine and its metabolites is challenging since the metabolites theophylline and paraxanthine generate similar product and precursor ions. In this study, a new method was developed for the simultaneous analysis of caffeine, paraxanthine, theobromine and theophylline in horse urine using gas chromatography-mass spectrometry (GC-MS). Urine samples were treated using solid-phase extraction followed by the elution with dichloromethane-isopropanol (90:10) after the pH was ad...
[New drugs for horses and production animals in 2021].
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere    July 5, 2022   Volume 50, Issue 3 195-199 doi: 10.1055/a-1849-1770
Emmerich IU.In 2021, one novel pharmaceutical agent for horses or food-producing animals was released on the German market, making the anti-haemorrhagic etamsylate (Hemosilate) available for horses, cattle, pigs, sheep, goats, dogs and cats, for the first time. The authorization of one established veterinary active ingredient was extended to an additional species: The endectocide eprinomectin (Eprecis) from the group of macrocyclic lactones was also approved for sheeps and goats. Additionally, two veterinary formulations with a new active substance content (bromhexine, tiamulin) and one active ingredient ...
Characterization of growth hormone secretagogue small molecule ibutamoren (MK-0677) and its possible metabolites in thoroughbred horses for doping control.
Rapid communications in mass spectrometry : RCM    June 19, 2022   Volume 36, Issue 18 e9337 doi: 10.1002/rcm.9337
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Koshy SA.It is important to remember that performance-enhancing agents such as non-peptide growth hormone secretagogues present a significant risk of abuse. Ibutamoren (MK-0677) is a potent, long-acting, selective non-peptide growth hormone secretagogue that can be taken orally. Methods: This study examines ibutamoren and its metabolites in thoroughbred horses after oral administration. Liquid chromatography/high-resolution mass spectrometry was used to determine the probable structures of the detected metabolites. Results: In this study, 22 metabolites of ibutamoren were identified (17 phase I and 5 p...
Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis.
Irish veterinary journal    May 14, 2022   Volume 75, Issue 1 11 doi: 10.1186/s13620-022-00215-8
Machin J, Brewer K, Morales-Briceno A, Fenger C, Maylin G, Tobin T.Zilpaterol is a β2-adrenergic agonist medication approved in certain countries as a cattle feed additive to improve carcass quality. Trace amounts of Zilpaterol can transfer to horse feed, yielding equine urinary "identifications" of Zilpaterol. These "identifications" occur because Zilpaterol is highly bioavailable in horses, resistant to biotransformation and excreted as unchanged Zilpaterol in urine, where it has a 5 day or so terminal half-life.In horses, urinary steady-state concentrations are reached 25 days (5 half-lives) after exposure to contaminated feed. Zilpaterol readily presen...
Monitoring anthelmintic use in horses.
The Veterinary record    May 7, 2022   Volume 190, Issue 9 373 doi: 10.1002/vetr.1767
Mair T, Shrubb J, Rendle D, Scott C, Hunter G, Parker R, Robinson N, Dean R.No abstract available
A quantitative method for the simultaneous detection of SR9009 and SR9011 in equine plasma using liquid chromatography-electrospray ionization-tandem mass spectrometry.
Drug testing and analysis    April 19, 2022   Volume 14, Issue 8 1532-1538 doi: 10.1002/dta.3271
Kwak YB, Yu J, Yoo HH.SR9009 and SR9011 are metabolic modulators pharmacologically targeting REV-ERB receptors as synthetic agonists. A liquid chromatography-tandem mass spectrometry method for the detection of SR9009 and SR9011 in equine plasma was developed and validated. Plasma samples were pretreated by protein precipitation with methanol and were loaded onto an ACQUITY ultra performance liquid chromatography high-strength silica C18 column (2.1 × 150 mm, 1.8 μm) for chromatographic separation. The mobile phase consisted of 5-mM ammonium formate (pH 3.0) in distilled water and 0.1% formic acid in ac...
Pharmacokinetics of glaucine after intravenous and oral administrations and detection of systemic aporphine alkaloids after ingestion of tulip poplar shavings in horses.
Journal of veterinary pharmacology and therapeutics    April 8, 2022   Volume 45, Issue 3 273-282 doi: 10.1111/jvp.13057
Haughan JE, Missanelli JR, You Y, Stefanovski D, Soma LR, Robinson MA.Glaucine, an aporphine alkaloid with anti-tussive, anti-inflammatory, and anti-nociceptive properties, has been identified in post-race samples from racehorses. To investigate pharmacokinetics of glaucine in horses, a three-way crossover study of intravenous and oral glaucine (0.1 mg/kg) and orally administered tulip poplar shavings (50 g shavings = 0.001 mg/kg glaucine) was performed in six horses. A two-compartment model best described IV administration with alpha ( ) and beta ( ) half-life lives of 0.3 (0.1-0.7) and 3.1 (2.4-7.8) h, respectively. The area under the curve ( ) was ...
Intelligence benefit of the 3-methoxytyramine to tyramine ratio in equine urine.
Drug testing and analysis    April 5, 2022   Volume 14, Issue 5 936-942 doi: 10.1002/dta.3264
Elbourne M, Cawley A, Stanley S, Bowen C, Fu S.Equine urine analysis has evolved over time to detect thousands of urinary compounds for doping control in the horse racing industry. The longitudinal assessment of 3-methoxytyramine to tyramine ratio (3-MT/T) values in equine urine by GC-MS profiling was investigated to support the Racing NSW Equine Biological Passport (EBP) for detection of dopaminergic manipulation in racehorses. This involved comparison of routine urine samples to administration studies of Sinemet, a common Parkinson's disease medication containing levodopa. Using an endogenous reference compound (ERC) in a urinary ratio e...
Equine metabolism of the growth hormone secretagogue MK-0677 in vitro and in urine and plasma following oral administration.
Drug testing and analysis    March 25, 2022   Volume 14, Issue 7 1273-1290 doi: 10.1002/dta.3252
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Van Eenoo P.Ibutamoren mesylate, or MK-0677, is an orally active, nonpeptide growth hormone secretagogue that has been developed to stimulate excretion of endogenous growth hormone. It has been evaluated for the treatment of a range of clinical conditions but is not available therapeutically. Nonetheless, MK-0677 is widely available to purchase online, sold as 'supplement' products. The mode of action and relative ease of purchase make MK-0677 a potential threat with regard to sports doping. The aim of this study was to investigate the metabolism of MK0677 in the horse following in vitro incubation and or...
Long-term monitoring of IOX4 in horse hair and its longitudinal distribution with segmental analysis using liquid chromatography/electrospray ionization Q Exactive high-resolution mass spectrometry for the purpose of doping control.
Drug testing and analysis    March 7, 2022   Volume 14, Issue 7 1244-1254 doi: 10.1002/dta.3247
Ishii H, Shibuya M, So YM, Wong JKY, Ho ENM, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Yamada M, Leung GN.IOX4, a hypoxia-inducible factor stabilizer, is classified as a banned substance for horses in both horse racing and equestrian sports. We recently reported the pharmacokinetic profiles of IOX4 in horse plasma and urine and also identified potential monitoring targets for the doping control purpose. In this study, a long-term longitudinal analysis of IOX4 in horse hair after a nasoesophageal administration of IOX4 (500 mg/day for 3 days) to three thoroughbred mares is presented for the first time for controlling the abuse/misuse of IOX4. Six bunches of mane hair were collected at 0 (pre), ...
Measurements of hydrocortisone and cortisone for longitudinal profiling of equine plasma by liquid chromatography-tandem mass spectrometry.
Drug testing and analysis    March 4, 2022   Volume 14, Issue 5 943-952 doi: 10.1002/dta.3244
Tou K, Cawley A, Bowen C, Sornalingam K, Fu S.The conventional detection of exogenous drugs in equine doping samples has been used for confirmation and subsequent prosecution of participants responsible. In recent years, alternative methods using indirect detection have been investigated due to the expanding number of pharmaceutical agents available with the potential of misuse. The monitoring of endogenous biomarkers such as hydrocortisone (HC) has been studied in equine urine with an international threshold of 1 μg/ml established; however, there is no current threshold for equine plasma. The aim of this research was to investigate pl...
Profiling Urinary Sulfate Metabolites With Mass Spectrometry.
Frontiers in molecular biosciences    February 23, 2022   Volume 9 829511 doi: 10.3389/fmolb.2022.829511
Fitzgerald CCJ, Hedman R, Uduwela DR, Paszerbovics B, Carroll AJ, Neeman T, Cawley A, Brooker L, McLeod MD.The study of urinary phase II sulfate metabolites is central to understanding the role and fate of endogenous and exogenous compounds in biological systems. This study describes a new workflow for the untargeted metabolic profiling of sulfated metabolites in a urine matrix. Analysis was performed using ultra-high-performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) with data dependent acquisition (DDA) coupled to an automated script-based data processing pipeline and differential metabolite level analysis. Sulfates were identified through -means clustering...
Acquisition and use of analgesic drugs by horse owners in the United States.
Equine veterinary journal    February 23, 2022   Volume 55, Issue 1 69-77 doi: 10.1111/evj.13564
Sellon DC, Sanz M, Kopper JJ.Little is known about the acquisition and use of equine analgesic drugs by horse owners in the United States (US). Objective: To determine factors associated with possession of analgesic drugs by horse owners in the US or with analgesic drug acquisition from sources noncompliant with a valid veterinarian-client-patient (VCPR) relationship. Methods: Cross-sectional survey. Methods: An internet-based questionnaire included items related to experiences with horses and equine analgesic drugs. Factors associated with possession of ≥5 types of analgesic drugs and with the acquisition of drugs from...