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.
Drudge JH, Lyons ET, Tolliver SC.Three formulations of cambendazole were evaluated for anthelmintic activity by critical testing method in 21 horses. Cambendazole suspension was administered via stomach tube at the dose rate of 10 mg/kg to 3 horses and at the dose rate of 20 mg/kg to 3 horses. Cambendazole paste was given intraorally to 8 horses, and the pellet formulation was fed to 7 horses at the dose rate of 20 mg/kg. Anthelmintic activity of cambendazole was similar for all dose rates and formulations. Gasterophilus intestinalis, Gasterophilus nasalis, Draschia megastoma, Anoplocephala perfoliata, and Anoplocephala magna...
Sisodia CS, Kramer LL, Gupta VS, Lerner DJ, Taksas L.Pharmacological disposition of chloramphenicol was studied in horses. Minimum levels of the antibiotic (greater than or equal to 5 mu g/ml) in blood or plasma recommended to combat infections could not be achieved by 4.4 and 8.8 mg/kg I.V. or 30 and 50 mg/kg I.M. or 30 mg/kg oral (as palmitate salt) doses of chloramphenicol. Increasing the dose to 19.8 and 26.4 mg/kg I.V. provided such levels for about two and three hours respectively. A combination of 20 mg/kg I.V. and 30 mg/kg I.M. administered simultaneously did not provide more prolonged levels than 26.4 mg/kg I.V. alone. Chloramphenicol s...
Hariharan H, Barnum DA, Mitchell WR.Prevalence of antimicrobial drug resistance among over 3000 clinical isolates of animal pathogens in Ontario during 1971-72 has been studied. A high number of multiple resistance patterns is prevalent among members of Enterobacteriaceae, especially Escherichia coli and Salmonella typhimurium. The most common resistance pattern among bovine strains was against not less than six drugs in common use. Among different animal species the bovine population was found to be the source of a high percentage of chloramphenicol resistant E. coli and S. typhimurium organisms. All the isolates resistant to t...
Stewart GA.The research focuses on understanding the physiological responses, mainly cardiovascular and respiratory, of racehorses during exercise and how drugs can impact these responses. The study aims to set up a […]
Reed RA, Carroll AT, Dantino SC, Quandt JE, Barletta M, Sakai DM.To determine the influence of xylazine infusion on survival to discharge and describe the associated intraoperative requirement for isoflurane, use of positive inotropes and vasopressors, and recovery time in horses undergoing exploratory laparotomy. Methods: Retrospective cohort study. Methods: A total of 352 horses. Methods: Medical records of horses undergoing anesthesia for exploratory laparotomy from January 2018 to December 2023 were reviewed. Data collected included survival to discharge, results of diagnostic tests, end tidal isoflurane concentration (FE'Iso), use of vasopressors/inotr...
Dedecker L, Ceriotti S, Mora-Pereira M, Knych HK, Zuber E, Lascola KM.To describe and compare the pulmonary and plasma pharmacokinetics of different oral formulations of chloramphenicol administered as a single dose to healthy adult horses. Unassigned: A single dose of chloramphenicol was administered to 6 healthy, university-owned fasted adult horses IV (25 mg/kg), orally as commercial tablets (50 mg/kg), or orally or intragastrically as compounded suspension (50 mg/kg), according to a randomized crossover protocol. Plasma was collected 5, 10, 15, 20, and 30 minutes and 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours after drug administration. Bronchoalveolar lavage (B...
The AnalystJanuary 23, 2025
doi: 10.1039/d4an01501k
Göktaş EF, Kabil E, Söylemez Yeşilçimen E, Dirikolu L.Various technical methodologies are required to accurately detect substances of different chemical and pharmacological properties in biological samples, which are increasing in number and variety daily. Therefore, laboratories where many samples and different factors are analyzed simultaneously need methods with easy sample preparation, short analysis times and low analysis costs. In this study, the objective was to scan substances susceptible to chemical degradation, amenable to analysis without hydrolysis, and exhibiting short-term stability by employing a straightforward, expeditious, and c...
Kodaira K, Kakizaki M, Nagata SI, Ode H, Okano A, Tamura N, Mizobe F, Matsuda Y, Kurimoto S, Aida H.To investigate the pharmacodynamics and pharmacokinetics of rocuronium administered by bolus injection to sevoflurane-anesthetized horses. Methods: Prospective, experimental, crossover study. Methods: Five healthy adult Thoroughbred horses (body mass 368-470 kg, three females and two males). Methods: Each horse was anesthetized twice with sevoflurane and assigned to be administered rocuronium bromide intravenously: 0.2 mg kg (R02) or 0.4 mg kg (R04). There was a minimum 2 week washout period between experiments. During anesthesia, the peroneal nerve was stimulated (train-of-four) and neuromusc...
Larson MA, Credille BC, Berghaus LJ, Papich MG, Beasley EM.To investigate the disposition of enrofloxacin and its active metabolite, ciprofloxacin, in plasma, pulmonary epithelial lining fluid (PELF), peritoneal fluid, and CSF in horses following IV administration of enrofloxacin at doses of 5 mg/kg and 7.5 mg/kg of body weight. Unassigned: 6 healthy, mature mares were randomly assigned to receive a single dose of enrofloxacin at either 5 mg/kg or 7.5 mg/kg in a crossover design with a washout period of 10 days. Concentrations of enrofloxacin and ciprofloxacin were determined in plasma, PELF, peritoneal fluid, and CSF. Unassigned: Both doses of enrofl...
Harding C, Viljanto M, Hincks P, Habershon-Butcher J, Paine SW.Omeprazole is a gastric acid secretion inhibitor used as an effective anti-ulcer drug. Based on oral administration studies, its International Screening Limit (ISL) was established in plasma and urine at 1 ng/mL with a Detection Time (DT) of 48 h. A novel formulation of injectable omeprazole has since been released, and therefore, a pharmacokinetic study was performed to assess the DT above the ISL against current advice. Six Thoroughbred horses were given four repeated weekly intramuscular administrations of omeprazole (4 mg/kg). Plasma and urine omeprazole concentrations were measured ...
Guzmán JFC, Gontijo AS, Melgaço ES, Faria SA, Baldi MLC, Sousa LN, Wenceslau RR, Fantini P, Xavier ABDS, Beier SL.Morphine has significant clinical and analgesic effects in horses, but its impact on the gastrointestinal tract requires further understanding. This study assessed the analgesic and gastrointestinal effects of morphine in horses undergoing elective orchiectomy in the quadrupedal position. Thirty uncastrated male horses were randomly assigned to three groups: orchiectomy without morphine and sedation protocol (OSM), orchiectomy with morphine and sedation protocol (OM), and administration of morphine alone in the absence of orchiectomy (M). The anesthetic protocol involved acepromazine (0.05 mg/...
Hordle T, Ranninger E, Bettschart-Wolfensberger R.A 24 year old warmblood mare (case 1) and a 12 year old Holsteiner gelding (case 2) were anaesthetized for bursoscopy and phacoemulsification, respectively. Both were premedicated with intramuscular acepromazine (30 μg kg-1). The horses were sedated with intravenous (IV) medetomidine (7-9 μg kg-1 to effect), before anaesthetic induction with ketamine-diazepam. Anaesthesia was maintained with isoflurane in a mixture of oxygen and medical air, alongside a medetomidine constant rate infusion at 3.5 μg kg-1 hour-1. In recovery, 3 and 5 μg kg-1 of medetomidine were administered IV to cases 1 an...
Yu R, Jusko WJ.This study assesses the pharmacokinetics (PK) of published methylprednisolone (MPL) data in horses following intra-articular (IA) administration of MPL acetate (MPA) and the associated adrenal suppression. The concentrations of MPL/MPA in synovial fluid, blood, and urine, as well as hydrocortisone (HC) in plasma, were digitized from multiple sources in the literature. A minimal physiologically based pharmacokinetic model and a linked indirect response model with a circadian rhythm baseline were applied. Concentrations of MPA in joints followed a triexponential decay, converting to MPL. The cle...
Gutierrez SO, Kilcoyne I, Saldinger LK, Woodward L, Nieto JE.To determine if different methods of perfusate instillation influence synovial amikacin concentrations in the radiocarpal joint (RCJ) after IV regional limb perfusion (IVRLP). Unassigned: 6 healthy horses received an IVRLP using 2 different methods: (1) 2 g amikacin followed by 52 mL 0.9% NaCl (60 mL total; perfusate-A) and (2) 2 g amikacin diluted to 60 mL with 0.9% NaCl (perfusate-D). For both methods, the perfusion was administered over 5 minutes. Joint fluid from the RCJ was sampled at 10, 15, 20, 25, and 30 minutes after instillation of the perfusate. Systemic concentrations of amikacin w...
Gorenberg EB, Slack J, Stefanovski D, Theiss D, Hopster K.Dobutamine is a first-line therapy for hypotension in anaesthetised horses, but the effects on haemodynamic parameters in standing and anaesthetised horses are not well studied. Objective: To investigate the effects of dobutamine in escalating dosages on haemodynamic performance in awake and anaesthetised horses. Methods: Randomised cross-over experimental study. Methods: Six healthy adult horses were enrolled, including both standing and isoflurane-anaesthetised experiments with 1-week washout. Heart rate, mean arterial pressure (MAP), central venous pressure, pulmonary arterial pressure, and...
Obrochta B, Tapio H, Raekallio M, Gracia Calvo LA, Pöyhönen RR, Hagman K, Jantunen N, Karikoski N.Sedation in horses is typically achieved using alpha-2 adrenoceptor agonists, although their use is associated with multiple side effects. A peripheral alpha-2 adrenoceptor antagonist, vatinoxan, can alleviate many of these. Objective: To evaluate the effects of vatinoxan infusion on gastrointestinal motility, sedation, and antinociception in horses sedated with detomidine infusion. Methods: Randomised, blinded cross-over in vivo experiments. Methods: Eight horses were given two 4-h infusions: detomidine (0.01 mg/kg + 0.015 mg/kg/h IV) (DET) and a combination of detomidine and vatinoxa...
Kintz P, Baudry M, Gheddar L.Trazodone, a medicine registered for human, is a serotonin agonist-antagonist. At low dose, the drug is sedative due to its antagonist properties. At high dose, it is an agonist with anxiolytic and antidepressant actions. Trazodone can be administered to the horse to reduce anxiety. However, according to the anti-doping rules for horses, the presence of trazodone in blood or urine is considered as a violation which will produce a suspension of both the athlete and the horse as the drug is listed banned on the International Federation of Horseracing Authorities prohibited substances list. As a ...
Roccaro M, Rinnovati R, Stucchi L, La Rocca F, Cascio G, Peli A.Doping in racehorses is a threat to horse welfare and the integrity of the sport. Despite its relevance, the literature on the prevalence of anti-doping violations worldwide is limited. Objective: To analyse anti-doping violations in racehorses in Italy. Methods: Retrospective observational study. Methods: Data on horse races, anti-doping testing, and confirmed violations between 2014 and 2022 were collected and analysed. Positivity rates, most common drug classes and parent drugs, and differences between trotting and galloping horses were investigated. Results: During the considered 9-year ti...
Ho HSM, Farrington AF, Ho ENM, Wong WT.2-Hydroxyethyl salicylate (2HES), a nonsteroidal anti-inflammatory drug (NSAID), is a medication to treat musculoskeletal injuries and inflammation swelling of humans and horses. Its misuse could affect the performance of horses and mask injuries, which could pose significant health risks. In horseracing, it is reported as an adverse finding once detected in competition. The metabolism of 2HES in either human or horse has not been reported, and therefore, little is known about its metabolic fate. This paper describes the in vivo metabolism of 2HES in horse with an objective to identify the mo...
Pain management in horses plays a pivotal role in the therapeutic approach to several diseases. Horses have cannabinoid receptors at the level of dorsal root ganglia, blood vessels, and synoviocytes that can be up or down- regulated by inflammatory conditions, justifying the possible efficacy of exogenous cannabinoids (i.e., phytocannabinoids) in managing several painful pathologies in this animal species. However, the current use of supplements containing cannabidiol (CBD) in equines is based on anecdotal evidence, without the support of sufficient pharmacokinetic studies. In humans, the conc...
Kamutzki CJ, Emmerich IU.In 2024, there was no release of a novel pharmaceutical agent for horses and food-producing animals or an extension of existing active ingredients to other animal species on the German veterinary medicinal products market. Formic acid is now available for a new form of treatment, the short-term treatment of honeybees, and clenbuterol is available in a new dosage form, as an oral solution for horses. In the field of immunological veterinary medicinal products, three new vaccines were launched on the German veterinary medicinal products market. For the first time, a vaccine against in cattle, a...
Gao T, Liu X, Qiu D, Li Y, Qiu Z, Qi J, Li S, Guo X, Zhang Y, Wang Z, Gao X, Ma Y, Ma T.Cefquinome is used to treat septicemia caused by () and respiratory infections caused by subsp. in foals. However, studies reporting the use of cefquinome to target as pathogens of sepsis are lacking. Therefore, this study aimed to determine the optimal dosage regimen for cefquinome against using a PK/PD model. After the administration of 1 mg/kg cefquinome (intramuscularly or intravenously), blood samples were collected at different time points to determine the serum concentration of cefquinome via HPLC. The pharmacokinetic parameters were evaluated via NCA (WinNonlin 5.2.1 software). Th...
Chambers A.All anti-doping programmes face financial constraints and monitoring trends in medication use or abuse in a population of racehorses can be difficult and expensive. Obtaining biological samples is the primary method of anti-doping control in individual horses or stables of horses but can be invasive and expensive. Another important practice of anti-doping control has been the confiscation of used and filled syringes by regulators for individual forensic analysis. Pooled samples testing involves the testing of multiple individual samples together as one composite sample. This pooled sample appr...
Bardhi A, Lanci A, Mannini A, Castagnetti C, Barbarossa A.Background: Although antibiotic resistance is a well-known issue in veterinary medicine, studies proposing real-time therapeutic monitoring (TDM) are lacking. The objective of the present study was to develop a simple and rapid protocol for the real-time therapeutic monitoring of antibiotics in horses and dogs. Methods: A reliable TDM protocol should encompass guidelines for the definition of plasma/serum collection time points, sample management by the clinical staff, transportation to the laboratory, and the availability of robust and swift analytical technologies. Ampicillin and sulbactam w...
Ho HSM, Mizzi JX, Ho ENM, Wong WT.Ranitidine is a histamine H-receptor antagonist commonly used to treat gastric ulceration in horses. The author's laboratory conducted a study some years ago in the early 2000s on its metabolism as well as its urinary elimination profile in two geldings. With the technology advancement as well as popularity of blood for doping control testing, the laboratory has recently conducted another administration trials of the substance in six horses to study the in vivo metabolism of ranitidine, aiming to identify and reinvestigate the appropriate target(s) for controlling misuse of ranitidine in hors...
Vinijkumthorn R, Prapaiwan N, Chotikaprakal T, Prompiram P, Phaonakrop N, Roytrakul S, Tesena P.Phenylbutazone (PBZ) can potentially induce gastrointestinal ulceration, and early detection of PBZ-induced gastroenteropathy will be useful for the diagnosis, treatment, and prevention of PBZ toxicity. Objective: To identify putative proteins associated with equine gastric ulcer syndrome after clinical dose (4.4 mg/kg) administration of PBZ by proteomic study. Methods: In vivo experiments. Methods: Proteomic analysis using LC-MS/MS compared protein expression in serum and faeces of seven PBZ-treated horses with seven placebo-treated controls, and a novel putative biomarker was validated via...
Sayler B, Manship AJ, Davis J, Taylor J, Gilliam L.Chloramphenicol is a broad-spectrum antibiotic used in equine practice. It is known to produce adverse effects of hyporexia/anorexia after oral administration. Administration per rectum (PR) could mitigate the appetite suppression seen with oral administration and allow its use in horses unable to receive oral medications. The objectives of this study were to evaluate the relative bioavailability of chloramphenicol administered PR or via nasogastric tube (NGT) and determine relevant pharmacokinetic/pharmacodynamic parameters and metabolic ratios. Ten healthy, adult horses were administered chl...
Bardhi A, Barbarossa A, Joubert A, Gehring R, Lambertini C, Romagnoli N.Dried blood spot (DBS) sampling has emerged as a promising microsampling technique in biomedical and clinical research, offering advantages such as reduced invasiveness, minimal blood volume requirements, and enhanced analyte stability. Although well established in human medicine for neonatal screening and diagnostic applications, its potential in veterinary pharmacology remains underexplored. This study investigated the feasibility of using DBS samples to quantify anesthetic agents-ketamine and medetomidine in cats and lidocaine in horses-during routine surgical procedures at a veterinary tea...
Sobhy A, Nomir AG, Hamed MA, Abumandour MMA, El-Kammar M.The current study was prepared to compare the efficacy of xylazine-lidocaine HCl and detomidine-lidocaine HCl following caudal epidural injection in horses, evaluating sedation, analgesia, physiological parameters, and hemato-biochemical values. This study was applied to six healthy adult horses (300-350 kg, > 4 years of age). The horses were randomly divided into two equal groups. Group 1 (seven horses) received xylazine (0.17 mg/kg bwt) + lidocaine HCl (0.06 mg/kg bwt), while Group 2 received detomidine (0.03 mg/kg bwt) + lidocaine HCl (0.06 mg/kg bwt) via caudal epidural inje...
So YM, Kwok WH, Tang CWY, Wong COL, Wan TSM, Ho ENM.This paper describes the studies of the in vitro biotransformation of nandrolone decanoate and its metabolic fate in equine plasma and urine after intramuscular administration to castrated thoroughbred horses. The in vitro metabolic study was performed using homogenised horse liver, and the more prominent in vitro biotransformation pathways were found to include hydrolysis, reduction, oxidation and sulfation, mainly resulting in seven Phase I metabolites and one Phase II metabolite. The administration study of nandrolone decanoate was carried out using three retired thoroughbred geldings, e...
Kuroda T, Minamijima Y, Niwa H, Mita H, Nomura M, Ohta M.A pharmacokinetics/pharmacodynamics (PK/PD) approach was used to determine the dosage regimens of trimethoprim/sulfamethoxazole for methicillin-resistant Staphylococcus aureus (MRSA) infections after intravenous (IV) and per os (PO) administration in horses. Methods: Trimethoprim/sulfamethoxazole plasma concentrations were measured in six horses after a single IV administration of 15 mg/kg (2.5 mg/kg trimethoprim and 12.5 mg/kg sulfamethoxazole) and PO administration of 30 mg/kg (5.0 mg/kg trimethoprim and 25.0 mg/kg sulfamethoxazole). The data were modeled using a nonlinear mixed-effects mode...
Bacon EK, Finno CJ, Donnelly CG, Haase B, Knych HK, Velie BD.Clinical assessments of equine sedation typically rely on subjective observations, the accuracy of which is paramount to the safety of equine veterinary procedures. Methods: To assess the degree in which subjective clinical sedative evaluations reflect pharmacokinetic measurements of equine drug metabolism, xylazine hydrochloride, an alpha-2 adrenoreceptor agonist, was administered to 36 horses of varying breed and age at a dosage of 0.5 mg/kg body weight. Subjective clinical parameters were scored at 5-, 15-, 30-, 45- and 60-minutes post xylazine administration and included responsiveness to ...
Blanton A, Glass KG, Bayer J, Baetge C, Watanabe R, Sampson SN, Lépiz M, Moreno K, Ida KK.Pregabalin reduces excitatory neurotransmitter release and is used for anxiolysis in humans, cats, and horses. The effects of pregabalin on equine recovery following isoflurane anaesthesia are unknown. Objective: To determine if pre-anaesthetic oral pregabalin influences recovery time and/or quality from isoflurane anaesthesia in horses undergoing elective magnetic resonance imaging (MRI) of the appendicular skeleton. Methods: Retrospective cohort study. Methods: Anaesthetic and recovery data from 52 healthy horses in which pregabalin (PG) was administered and 76 control horses (CG) undergoing...
Wermer K, Korbacska-Kutasi O, Berkecz R, Csupor D, Ágh N, Sztojkov-Ivanov A, Cserhalmi D.Cannabidiol (CBD) has shown potential therapeutic benefits in veterinary medicine, but further investigations are needed to establish its pharmacokinetics and therapeutic dosing in horses and ponies. The present study aimed to investigate the pharmacokinetic properties of CBD in Connemara ponies following oral administration of CBD oil. Unassigned: Ten healthy ponies received a single oral dose of CBD oil at 2 mg/kg. Blood samples were collected before dosing and up to 16 days post-administration, with physical examinations conducted at baseline and at 8, 12, and 24 h post-dose. Addition...
