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.
Supramolecular Solvent Extraction for Doping Control Analysis of Prohibited Substances in Horse Urine. Despite the recent success in introducing supramolecular solvents (SUPRAS)-based extraction to drug analysis, its application and robustness in day-to-day regular urine testing have yet to be demonstrated. Moreover, the applicability of SUPRAS in equine doping control testing remains unexplored. In this work, we have successfully developed for the first time a simple, rapid, inexpensive, and environmentally friendly SUPRAS extraction method for analyzing 76 prohibited substances of different classes (selective androgen receptor modulators, hypoxia-inducible factor prolyl hydroxylase inhibitors...
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,...
Antibiofilm and resistance-modulating properties of tt-farnesol against Streptococcus equi subsp. equi and zooepidemicus. The aim of this study was to investigate the antibacterial, antibiofilm and modulating activities of trans-trans-farnesol (tt-farnesol) on two strains of Streptococcus equi subsp. equi and two strains of S. equi subsp. zooepidemicus, pathogenic or commensal bacteria of horses. Tt-farnesol showed bactericidal activity against all tested strains, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) between 8 and 4 μg/mL. The sesquiterpene caused significant damage to the bacterial membrane, and its antibacterial activity did not appear to depend on oxidat...
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...
Tafenoquine succinate inhibits the growth of the equine piroplasmosis hemoparasites Theileria equi and Babesia caballi. Equine piroplasmosis (EP) is a tick-borne disease of equids caused by the intraerythrocytic apicomplexan parasites Theileria equi, Babesia caballi and the recently identified Theileria haneyi. Acute cases can be severe, with anemia, jaundice, abortion or sudden death. Survivors remain lifelong carriers, serving as reservoirs for tick-borne and iatrogenic transmission. No vaccines are currently available, and control strategies rely heavily on accurate diagnostics and chemotherapeutic intervention. Imidocarb dipropionate (ID) is the current standard of care for both acute treatment and radical ...
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...
Antibiotics prescribing patterns and association with system-specific pathologies in equine veterinary practice: Insights from a 12-year study at a veterinary teaching hospital. Antibiotics are essential in veterinary medicine, enhancing animal health and welfare. However, widespread use contributes to resistance, increasing the risk of treatment failure and the transmission to humans. Objective: Analyze antibiotic prescribing practices in an equine internal medicine unit, focusing on factors influencing use, particularly Highest Priority Critically Important Antimicrobials (HPCIAs). Methods: 1315 adult equids, including horses, donkeys and mules, presented for different diseases to the Veterinary Teaching Hospital (VTH) of the University of Pisa from 2011 to 2023. Re...
Enrofloxacin induces mild and transient vascular alterations following regional limb perfusion in horses. Regional intravenous limb perfusion (RILP) is widely used in equine practice for achieving high local antimicrobial concentrations while minimizing systemic exposure. However, certain drugs, including enrofloxacin, have been associated with vascular irritation and thrombosis, and their thrombogenic potential remains poorly characterized. Objective: This study aimed to evaluate the thrombogenic potential of enrofloxacin administered via RILP in the cephalic vein of clinically healthy horses. Methods: Ten adult horses underwent RILP in both forelimbs: the right limb received 10 % enrofloxacin (1...
Videofluoroscopy shows clinically relevant changes in swallow metrics and esophageal transit in normal horses with xylazine, anticholinergic use, and varied feed consistency. To investigate the effects of varied feed consistency and administration of xylazine or N-butylscopolammonium bromide on 3 phases of swallowing and characterize esophageal motility following barium administration via nasoesophageal tube. Unassigned: 8 healthy horses were enrolled for 2.5 consecutive weeks. Horses underwent experimental videofluoroscopic swallow studies before and after sedated and anticholinergic interventions. Esophageal motility was assessed with barium administered via nasoesophageal tube and with barium-admixed feedstuffs of 3 consistencies with increasing viscosity. Phase...
Compounded oral doxycycline in late-term pregnant mares: pharmacokinetics, fetoplacental diffusion, and neonatal safety. Doxycycline is widely used in equine medicine, yet data on its pharmacokinetics and safety during late gestation are scarce. We investigated the pharmacokinetics, fetoplacental diffusion, and safety of compounded oral doxycycline in late-term pregnant mares. In the first experiment, six mares at 300 days of gestation received a single oral dose (10 mg/kg), and plasma concentrations were measured using LC-MS/MS. Pharmacokinetic analysis using non-compartmental and compartmental models showed rapid absorption, with a mean Cmax of about 6000 ng/mL reached within 0.8 h and a terminal half-life ...
Pharmacokinetics of a fipronil pour-on formulation and its efficacy against Dermacentor nitens (Acari: Ixodidae) in horses. The objective of this study was to standardize a stall-trial methodology for horses in order to evaluate the pharmacokinetics and efficacy of a 1 % fipronil pour-on formulation against Dermacentor nitens. Brazilian pony breed horses were housed in individual stalls within a covered barn and artificially infested with D. nitens larvae on alternate days from day -31 to -1 before treatment. The animals were treated on day 0 with a fipronil 1 % pour-on at a dose of 1 mg/Kg body weight. To determine the therapeutic efficacy, the number of engorged females naturally detached from control and t...
Evaluation of the impact of acepromazine on tissue oxygenation in horses sedated with detomidine. Sedation with α₂-agonists can impair microcirculation and oxygen delivery. This prospective randomized crossover study investigated whether administering acepromazine maleate before detomidine hydrochloride maintains higher peripheral tissue oxygen saturation (StO₂) in sedated horses. Eight healthy adult horses randomly received intravenous detomidine (10 μg/kg) either alone (D) or in combination with acepromazine (20 μg/kg; DA), with a one-week washout. Hemoglobin concentration and central venous oxygen saturation (ScvO₂) were measured at baseline. Tissue oxygen saturation, tissue ...
Pharmacokinetics and Safety of a Single Subcutaneous or Intramuscular Dose of Ketamine in Healthy Horses. Pharmacokinetics (PK) of intramuscular (IM) and subcutaneous (SC) ketamine in horses has not been described. This study aimed to evaluate the PK and safety of ketamine and its metabolites after a single SC or IM administration. In Phase 1, two horses received 0.5 or 1 mg/kg of ketamine via SC and IM routes. In Phase 2, eight horses received 0.5 mg/kg IM. Plasma or serum concentrations of ketamine and major metabolites were determined by a validated liquid chromatography-mass spectrometry method at baseline and selected intervals post-administration. Subcutaneous administration resulted in ...
Dexmedetomidine Prolongs the Duration of Ropivacaine Corneal Anesthesia After Subconjunctival Injection in Healthy Horses. To determine whether dexmedetomidine prolongs corneal anesthesia following subconjunctival ropivacaine injection in healthy equine eyes. Methods: Ten horses with normal ophthalmic exams were enrolled in a randomized, blinded, crossover experiment with a minimum 4-week washout between treatments. Baseline corneal touch thresholds (CTT, cm) were measured via esthesiometry and a subconjunctival injection was performed in the treatment eye with ropivacaine (R, 0.3 mL 0.5%) or dexmedetomidine-ropivacaine (DR, 0.1 mL 0.5 mg/mL + 0.2 mL 0.5%) and saline (control, 0.3 mL) in the contrala...
Physiological and behavioural effects of continuous remifentanil-xylazine administration in donkeys. Remifentanil and xylazine are used as continuous infusions to facilitate standing surgery in horses. Their use for this purpose has not been reported in donkeys. Objective: To evaluate the behavioural, sedative, and cardiorespiratory effects of continuous intravenous infusion of remifentanil and xylazine in donkeys. Methods: Non-blinded in vivo experiments. Methods: Ten donkeys were sedated with an intravenous bolus of xylazine (0.8 mg/kg). After 3 min, continuous infusions of xylazine (0.65 mg/kg/h) and remifentanil (6 μg/kg/h) were administered for 60 min. Cardiorespiratory physio...
Characterization of intramuscular Isoflupredone acetate in horses: pharmacokinetics and effects on anti-inflammatory mediators and plasma electrolytes. Corticosteroids, such as isoflupredone, are effective anti-inflammatory medications and as such are commonly used to treat inflammation associated with training and injuries in performance horses. While the pharmacokinetics and pharmacodynamics of isoflupredone acetate (IPA) following intra-articular administration to horses has been well described, studies characterizing intramuscular (IM) administration are lacking. The objective of the current study was to describe the pharmacokinetics and anti-inflammatory effects of IPA following IM administration to horses. Twelve horses received a singl...
Oral administration of pimobendan in healthy horses results in low plasma concentrations. To describe the pharmacokinetics of a single dose of pimobendan (Vetmedin) in healthy adult horses and provide preliminary evidence of the absorption of 2 compounded pimobendan formulations. Unassigned: From August 2022 through November 2022, 6 healthy adult horses were administered a single dose of 0.5 mg/kg pimobendan orally. A subset of 2 horses was also administered pimobendan, compounded as an oil-based suspension and a capsule formulation. Plasma was collected at times 0, 15, 30, and 45 minutes and 1, 2, 4, 8, 12, and 24 hours after administration. The plasma concentrations of pimobendan...
Metformin in the Horse: Pharmacokinetics and Detection Times Using Monte Carlo Simulations. The racehorse industry has strict regulations regarding the detection of prohibited substances in horses. Metformin, a diabetes medication, is a prohibited substance that has been reported in post-race blood and urine samples collected from racehorses. For further characterization of the disposition of metformin, 12 Thoroughbred horses were administered metformin orally and intravenously in a randomized, balanced, two-way crossover design. Serum and urine samples were collected, and drug concentrations determined via liquid chromatography-tandem mass spectrometry. The serum data were analyzed ...
Effects of Lidocaine Alone Versus Lidocaine-Dexmedetomidine Infusion on Pulmonary Gas Exchange and Respiratory Mechanics During Isoflurane Anesthesia in Horses. Dexmedetomidine improves pulmonary function in dogs and humans, but evidence in horses is scarce. This study evaluated dexmedetomidine infusion on oxygenation and respiratory mechanics in anesthetized horses. Twenty horses undergoing elective surgery were included in a prospective, non-randomized, observational study. Horses received either lidocaine alone (1.3 mg/kg over 15 min, then 3 mg/kg/hour; LIDO) or combined with dexmedetomidine (1.75 μg/kg over 15 min, then 1.75 μg/kg/hour; DL). Respiratory mechanics, gas exchange, and cardiovascular variables were recorded at baseline, post-loading...