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.
A randomized, masked, crossover, clinical trial of the efficacy and safety of nebulized albuterol sulfate and dexamethasone sodium phosphate in asthmatic horses. Nebulization of injectable dexamethasone sodium phosphate (DSP; 0.01 mg/kg) to horses with severe equine asthma (SEA) was previously found to be ineffective. Horses with SEA have marked bronchoconstriction that decreases peripheral lung deposition of nebulized drugs. Administration of a bronchodilator immediately before nebulizing dexamethasone may improve efficacy. Objective: Evaluate the therapeutic effects and optimal dose of nebulized DSP after nebulized albuterol in horses with SEA. Methods: Seven horses with SEA from a research herd. Methods: In this masked randomized crossover trial, h...
Long term safety and efficacy of a functionalized nanogel with endothelin-1 and bradykinin receptor antagonist peptides for treatment of osteoarthritis of the metacarpophalangeal and distal interphalangeal joints in horses: a descriptive clinical pilot study. Intra-articular drug delivery systems (DDS) are emerging as promising therapies for osteoarthritis (OA), yet their efficacy in spontaneous clinical cases remains largely untested. This uncontrolled, descriptive pilot study was designed to provide a proof of concept for the feasibility, safety, and preliminary clinical effects of intra-articular administration in sport horses with naturally occurring OA. The study involved a peptide-functionalized nanogel composed of chitosan and hyaluronic acid, delivering endothelin type A (BQ-123) and bradykinin B1 (R-954) receptor antagonists, which have pr...
Pharmacokinetic analysis and steady-state predictions of different preparations of metronidazole administered per rectum in adult horses. Manipulation of forms of rectally administered metronidazole to improve bioavailability in horses has not been reported. Objective: Evaluate the pharmacokinetics of 3 rectal metronidazole preparations compared to nasogastric (NG) administration. Methods: Seven healthy horses. Methods: Phase 1A was a randomized, 3-way crossover, single-dose pharmacokinetic study, and Phases 1B and 2 were non-randomized, single-dose follow-up studies. Metronidazole (20 mg/kg) was administered NG and rectally in water (RW20), as a rectal gel (RG), and in dimethyl sulfoxide (DMSO). Metronidazole (80 mg/kg) was a...
Pharmacokinetics of Topical Administration of Altrenogest in Mares and Implications for Human Health. Altrenogest is a synthetic progestogen widely used in equine reproductive management. Adverse effects to altrenogest have been reported in people with cutaneous exposure reported as the highest exposure pathway. Despite these reports, there has been no quantitative research to determine the capacity for altrenogest to be absorbed through skin. This study aimed to determine if cutaneous application of oral altrenogest results in systemic absorption in mares and to evaluate the influence of application site. A randomized, two-period, two-treatment crossover study was undertaken in eight mares. M...
Repeated intravenous dexamethasone administration causes transient changes in leukocyte parameters in healthy warmblood horses. To determine the effect of repeated IV administration of dexamethasone (0.06 mg/kg, q 24 h, twice) on WBC parameters in healthy adult horses. Unassigned: This prospective, longitudinal study was conducted from October 7 through November 5, 2024. Five warmblood mares received an IV dexamethasone sodium phosphate injection (DMI) at 0 and 24 hours and an IV injection with 0.9% sodium chloride solution at 48 and 72 hours. Blood samples were collected at 0, 6, 12, 24, 30, 36, 48, 72, 96, and 168 hours, and WBC parameters were evaluated using linear mixed-effects models. Unassigned: Leukocyte count,...
Pharmacokinetics and Anti-Inflammatory Effects of Intramuscular Betamethasone in Exercised Thoroughbred Horses. The pharmacokinetics and pharmacodynamics of betamethasone following intra-articular administration to horses have been described; however, studies characterizing intramuscular administration are lacking. Twenty-four horses received an intramuscular dose of 12 mg betamethasone sodium phosphate/betamethasone acetate. Blood and urine were collected at post administration for up to 408 h. Concentrations of betamethasone were determined using LC-MS/MS and pharmacokinetic parameters determined using a Population PK three-compartment model. The duration of pharmacodynamic effects was assessed by...
Pharmacopuncture with low-dose dexmedetomidine and saline aquapuncture at acupoint Governing Vessel 24 provides sedation in healthy adult horses. To evaluate sedation in horses following pharmacopuncture with dexmedetomidine at acupoint Governing Vessel 24 (GV-24) compared to aquapuncture at GV-24 or an equivalent dose of dexmedetomidine administered via IV or SC routes. Unassigned: 10 adult mares received 4 treatments in a blinded, randomized, crossover design: (1) dexmedetomidine administered at GV-24 (DexmedGV24; 1 μg/kg); (2) saline administered at GV-24 (SalineGV24; 1.5 mL); (3) dexmedetomidine administered SC on the lateral neck (DexmedSC; 1 μg/kg); or (4) dexmedetomidine administered IV (DexmedIV; 1 μg/kg). Sedation scores (fa...
Exposure to Subcutaneously Administered Butorphanol in Horses Pre-Treated With Detomidine or Detomidine-Vatinoxan. The aim of the study was to determine the exposure to subcutaneously administered butorphanol in horses pre-treated with intravenous (IV) detomidine, with or without vatinoxan, a peripherally selective alpha-adrenoceptor antagonist. Five healthy, adult horses received three IV treatments 7 days apart, in a randomized, cross-over design: detomidine 20 μg/kg (DET-B), detomidine 20 μg/kg with vatinoxan 200 μg/kg (DETVAT-B) and saline (S-B), all followed by 0.1 mg/kg of butorphanol administered subcutaneously 30 min later. Venous samples were collected between 10 and 270 min after...
Pharmacokinetics of Intragastric Ursodeoxycholic Acid and Its Impact on Bile Acid Profiles in Horses. Ursodeoxycholic acid (UDCA), a secondary bile acid (BA) with therapeutic applications, is standard therapy for cholestatic hepatopathies in humans. In recent years, its use has been increasingly explored in equine medicine for similar indications. Pharmacokinetic data for UDCA in horses are currently lacking. This study aimed to describe the pharmacokinetic parameters following a single intragastric administration of 15 mg/kg in nine healthy, fasted horses and to characterize the changes in their BA profiles. Plasma concentrations of UDCA were measured at specific time points using liquid ch...
Detection and Longitudinal Monitoring of Cyclosporine in Horse Plasma and Urine After Ocular Implant Administration. This paper describes the detection and longitudinal monitoring of cyclosporine in plasma and urine after subconjunctival implant administration in a horse. Sensitive liquid chromatography tandem mass spectroscopy (LC-MS/MS) methods for detecting cyclosporine in horse plasma and urine have been developed and validated, with estimated limits of detection down to 1 pg/mL in both matrices. The developed methods enabled longitudinal monitoring of cyclosporine levels in blood and urine samples collected over 6 months from a horse that had received an ocular cyclosporine implant.
Vonoprazan pharmacokinetics and effects on gastric pH following administration to fed and fasted horses. Current treatment options for equine gastric ulcer syndrome (EGUS), such as omeprazole-a proton pump inhibitor (PPI)-have notable limitations, including the need for administration on an empty stomach. Potassium-competitive acid blockers (P-CABs), such as vonoprazan, are a newer class of acid suppressants that offer several advantages over PPIs in humans and may provide similar benefits in horses. Objective: To describe the pharmacokinetics and effect of a single oral dose of vonoprazan on intragastric pH in horses. We hypothesised that vonoprazan would follow linear kinetics across the doses ...
Reducing Recurrence in Equine Corneolimbal SCC: Outcomes of Adjunctive Cisplatin Biodegradable Bead Therapy. (1) Context: Squamous cell carcinoma (SCC) is the most prevalent ocular neoplasm in horses, with a reported 45% recurrence rate when managed by surgery alone. (2) Objective: To evaluate the effect of adjunctive cisplatin biodegradable beads (CBBs) on recurrence rates of equine corneolimbal squamous cell carcinoma (SCC) and to document associated adverse effects. (3) Methods: Seventeen cases of histopathologically confirmed corneolimbal SCC in horses were retrospectively identified. Masses were surgically excised by keratectomy and/or conjunctivectomy under general anesthesia, followed by impla...
Development and validation of general urine screening method for performance enhancing drugs in racehorses utilizing liquid chromatography-high resolution mass spectrometry (LC-HRMS). The complexity of the drug market and the constant updating of drugs have been challenging issues for drug regulatory authorities. In this manuscript, a high-throughput automated assay based on Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS) suitable for use as an initial testing procedure covering multiple classes of compounds prohibited in horse racing is described. The assay requires a 250-μL urine aliquot, which is subjected to enzymatic hydrolysis followed by Biotage Isolute supported liquid extraction plates using Biotage Extrahera system, evaporation, and reconstituti...
Effects of Sedation on Rectal Temperature During Equine Dental Procedures Performed in Cold to Warm Ambient Temperatures. Sedation is important for safe equine dental procedures, but it is unknown if there is a higher risk of sedation causing hypothermia in procedures performed during cold months. The authors hypothesize that sedation for a dental procedure will significantly decrease rectal body temperature in cold as compared to warm ambient temperatures. Adult equids ( = 246), from a private equine dentistry practice, that underwent dental equilibration, were selected for the study. Each horse's weight was estimated and sedation was administered intravenously (0.01 mg/kg detomidine and 0.01 mg/kg butor...
Antimicrobial prescribing guidelines for horses in Australia. The growing problem of antimicrobial resistance also affects equine veterinarians with increasing frequency. Antimicrobial stewardship and responsible prescribing are essential for a future in which effective antimicrobials are available, as it is unlikely that new antimicrobials will become available for use in horses. While antimicrobials are commonly used to treat equine infections, complications with therapy are also relatively common. Antimicrobial-associated diarrhoea, immune-mediated diseases, and nephrotoxicity have been reported as sequelae of antimicrobial therapy in equine practice....
Ivermectin toxicosis in a foal: Use of intravenous lipid emulsion therapy. This report describes a case of ivermectin toxicosis in a 4-day-old thoroughbred colt successfully treated with intravenous lipid emulsion (ILE) without complications. This case supports the use of ILE as a safe and effective therapy for the management of lipophilic drug toxicosis in foals. Key clinical message: Ivermectin toxicosis, though rare in equine neonates, can occur following accidental overdose and induces severe neurologic signs. In this case, ILE administration resulted in rapid neurologic improvement and complete recovery without adverse effects, supporting its use as a safe and e...
Administration study of somapacitan, a long-acting growth hormone derivative, in horse for doping control purpose. Somapacitan is the second generation of recombinant human growth hormone (rhGH) medication that retains the pharmacological effects of rhGH but exhibits a longer duration of action due to its reversible albumin-binding in the body. In general, the use of all recombinant growth hormone (rGH) analogues is banned by the human and animal sports regulatory authorities due to their anabolic and lipolytic effects. However, little is known about the elimination kinetics and biological effects of the newly introduced long-acting rhGH, somapacitan, in horses. This paper describes the administration stud...
Optimizing equine standing sedation: continuous infusion of detomidine and butorphanol enhances stability but prolongs ataxia. This study aimed to compare the sedation quality and cardiorespiratory and behavioral effects of detomidine administered intravenously, either in intermittent boluses or as a continuous rate infusion, with butorphanol in horses pre-medicated with acepromazine for odontoplasty procedures. Unassigned: A prospective clinical study was conducted with fifteen adult horses randomly assigned to two groups: Bolus group (BG, = 7) and Infusion group (IG, = 8). Both groups received acepromazine premedication, followed by detomidine administration (bolus or infusion). Butorphanol was administered either...
The impact of transdermal application site on pharmacokinetics and selected pharmacodynamics of buprenorphine in horses. To assess absorption after transdermal application of buprenorphine to different sites and assess behavioral, antinociceptive and adverse effects. It was hypothesized that the dose and site of transdermal buprenorphine administration would influence absorption, plasma drug concentrations, physiological, antinociceptive and behavioral effects in horses. Methods: Two-part study; prospective randomized balanced three-way crossover (study 1) and single-dose (study 2) experimental study. Methods: Six (study 1) and eight (study 2) horses, aged 3-14 years. Methods: In study 1, horses were administere...
The effect of cervical epidural injection of morphine and the combination of morphine and detomidine on recovery from anesthesia in adult horses. To evaluate the effect of cervical epidural injection of morphine alone and morphine in combination with detomidine on recovery from anesthesia in horses. Methods: Blinded, randomized, crossover, Latin square design. Methods: A group of six healthy adult horses aged 9 ± 3 years and weighing 471 ± 76 kg (mean ± standard deviation). Methods: Horses were administered each of three treatments during a 1 hour general anesthetic with a 4 day washout period. Treatments were: 1) cervical epidural injection of saline 0.011 mL kg (S); 2) morphine 0.1 mg kg (M); and 3) morphine 0.1 mg kg with detomidi...
Pregabalin contributes to increased recovery time from isoflurane anaesthesia for magnetic resonance imaging in horses. 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...
Evaluating the extent to which ataxia and responsiveness to stimuli reflect the efficacy of xylazine sedation using pharmacokinetics. 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 ...
Pharmacokinetics/pharmacodynamics analysis of trimethoprim and sulfamethoxazole for methicillin-resistant Staphylococcus aureus infection after intravenous and per os administration in Thoroughbred horses. 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...
The effects of a long-duration intravenous infusion of detomidine, with and without vatinoxan, on equine energy metabolism and urine composition. To assess the effects of a 4 hour detomidine constant rate infusion (CRI) with and without a vatinoxan CRI on energy metabolism and urine composition. Methods: Randomized, blinded, crossover study. Methods: Eight Finnhorses, 587 (550-620) kg [median (range)] and 13 (4-16) years old. Methods: Horses were administered an intravenous (IV) detomidine loading dose (0.01 mg kg) followed by 240 minutes CRI (0.015 mg kg hour) (DET) and the same detomidine protocol combined with an IV vatinoxan loading dose (0.15 mg kg) and CRI (0.05 mg kg hour) (DET+VAT). Blood samples for glucose, insulin, non-esteri...
Metabolic Studies of Nandrolone Decanoate in Castrated Horses After Intramuscular Administration. 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...
Pharmacokinetics of cannabidiol and its two main phase I metabolites in Connemara ponies. 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...
Efficacy of caudal epidural injection of Xylazine-Lidocaine HCl and detomidine-lidocaine HCl in domestic horses (Equus ferus caballus). 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...
Pharmacokinetics of Chloramphenicol and Chloramphenicol Glucuronide in Horses Following Administration Per Rectum or via Nasogastric Intubation. 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...
The proteomic differences and expression of fatty acid-binding protein 6 (FABP6) associated with gastrointestinal injury in horses with oral administration of a clinical dose of phenylbutazone. 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...