Topic:Pharmacology
Pharmacology in horses involves the study and application of drugs and medications to diagnose, treat, and prevent diseases and conditions in equine species. This field encompasses the understanding of pharmacokinetics and pharmacodynamics specific to horses, including how drugs are absorbed, distributed, metabolized, and excreted by the equine body. Commonly studied pharmacological agents in horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, sedatives, and anthelmintics. Research in equine pharmacology focuses on determining appropriate dosages, understanding drug interactions, and minimizing adverse effects. This page compiles peer-reviewed research studies and scholarly articles that investigate the efficacy, safety, and regulatory aspects of pharmacological interventions in equine veterinary practice.
Equine Protozoal Myeloencephalitis: An Ancient Parasite Meets Modern Compounding. EPM remains particularly rampant in racing populations due to transport stress, young age, and congregate housing conditions. For compounding pharmacists, understanding that we're managing chronic parasite suppression - not achieving cure - fundamentally changes our approach to formulation strategy, stability assessment, and client counseling. The two formulations presented separately represent years of refinement, demonstrating compounding's essential role when commercial products fall short.
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...
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...
Cannabidiol-induced cellular and matrix-associated responses in primary equine sarcoid cells. Sarcoids are locally invasive skin tumors in equids, associated with bovine papillomavirus. Objective: Address potential applications of cannabidiol (CBD) in veterinary medicine. We evaluated the response of equine sarcoid cells to CBD in vitro, focusing on viability, invasiveness, and matrix remodeling. Methods: Three primary sarcoid cell lines. Methods: Cells were treated with CBD (20, 6.75, 2.25, 0.75 μM) and incubated for 6, 24, 48, 72 hours. Cell viability, cytotoxicity, and apoptosis were assessed using the ApoTox-Glo Assay. Based on these results, further analyses were performed for ...
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...
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...
Survey describing the perspectives and practices of Australian veterinarians to pain management in horses. To describe Australian practices and attitudes regarding equine analgesia. Methods: Cross-sectional anonymous, voluntary survey of Australian veterinarians treating equine patients. Methods: Australian veterinarians in equine or mixed practices completed a six-section, 60-question survey between November 2019 to August 2020. Information was gathered on demographics, analgesia prescription, pain assessment and attitudes surrounding specific analgesics. Respondents assigned a pain score ranging from 0 to 10 for various conditions; these were averaged to give each respondent an "average pain scor...
Effects of intravenous oxytocin on plasma serotonin and trainability in horses. Oxytocin (OXT) plays a crucial role in regulating the serotonin (5-HT) system and behavior. Although previous studies have reported significant relationships among OXT, 5-HT, and behavioral responses, the effects of OXT on 5-HT concentrations and behavioral traits in horses remain poorly understood. This study aimed to investigate the effects of intravenous OXT administration on plasma 5-HT concentrations and trainability in horses. A crossover design was employed using eight horses, each receiving either a 10-IU intravenous dose of OXT or normal saline. Blood samples were collected at baselin...
Treatment with ertugliflozin mitigates the hyperinsulinemic response to intra-articular triamcinolone acetonide. Intra-articular (IA) corticosteroids can cause hyperinsulinemia, which can subsequently increase the risk of laminitis, particularly in horses with insulin dysregulation (ID). Sodium glucose cotransporter 2 inhibitors (SGLT2i), a drug class that is being utilised more commonly in horses with insulin dysregulation, could potentially be used to control post-IA corticosteroid hyperinsulinemia. Objective: To determine whether treatment with the SGLT2i drug ertugliflozin decreases hyperinsulinemia following intra-articular corticosteroid administration in metabolically normal horses. Methods: Prosp...
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...
Case Report: Inhaled salbutamol in the successful treatment of life-threatening acute hyperkalaemia in an anaesthetised horse. Hyperkalaemia is an uncommon complication of general anaesthesia in healthy horses. This case report describes the occurrence of life-threatening acute hyperkalaemia in a 13-year-old, female French Trotter anaesthetised for experimental right and left atrial 3D electro-anatomical mapping. Intra-operative development of hyperkalaemia (7.55 mmol/L) (Ref. 3.00-4.00 mmol/L) with atrial standstill on ECG necessitated transvenous ventricular pacing while initial treatment with insulin and glucose was initiated. Plasma potassium levels continued to increase (8.00 mmol/L) prompting adjunctive tr...
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 ...
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...
Evaluation of a nutraceutical for prevention of equine ulcer recurrence. The number of horses with equine squamous gastric disease (ESGD) and equine gastric glandular disease (EGGD) recurrence when pharmacological treatment is discontinued is high. Objective: To examine if a commercially available nutraceutical compound containing lecithin, pectin, and meadowsweet could prevent recurrence of both ESGD and EGGD after omeprazole treatment, evaluated by repeated gastroscopic examinations and saliva biomarkers. Methods: Blinded, randomised, placebo-controlled clinical trial. Methods: Thirty horses of mixed breeds and sex with a recent diagnosis and treatment of both ES...
Effect of transdermal melatonin on circulating cortisol and blood chemistry in horses exposed to transport stress. Our objective was to evaluate the effect of transdermal melatonin on physiological stress biomarkers in horses, with some subjected to transport stress. Sixteen horses were assigned to a 2 × 2 factorial design assessing treatment (melatonin vs. no melatonin) and transport status (transported vs. non-transported), creating four groups: Control (CON), Transport only (TRS), Melatonin only (MEL), and Melatonin plus Transport (MELTRS). Horses in melatonin groups received 24 mg/day transdermally for 21 days and transported groups underwent a 3-hour trailer ride on day 21. Day 21 blood samples were ...
Equine trypanosomiasis, a systematic review: Disease management. Equine trypanosomiasis is a neglected protozoal disease. Objective: To answer the study question: In equines what are the effects of disease management of trypanosomiasis on disease severity (individual level) and disease prevalence (population level) compared to no intervention? Methods: Systematic review. Methods: Studies were identified that described management of naturally occurring equine trypanosomiasis in any country following 'Preferred Reporting Items for Systematic Reviews and Meta-analyses' using eight international databases (1980-2022). Risk of bias was assessed using ROBINS-I. D...
Sodium-glucose transporters SGLT1 and SGLT2 in equine renal, hepatic and pancreatic tissue. Insulin dysregulation is a hallmark of equine metabolic syndrome (EMS), and in recent years, pharmacological treatment with sodium-dependent glucose transporter 2 inhibitors (SGLT2i) have shown promise in reducing the risk of hyperinsulinemia-associated laminitis in horses diagnosed with EMS. In humans and laboratory animals, this transporter protein is responsible for the majority of renal tubular glucose reabsorption, however, the presence of this and the related sodium-dependent glucose transporter 1 (SGLT1) have not yet been studied in equine kidneys. Additionally, studies in humans and la...
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 ...
Metformin Protects Against Persistent Atrial Fibrillation in an Equine Model. Horses are one of the few animals that spontaneously develop atrial fibrillation (AF), making them a powerful model for studying AF mechanisms and treatment effects. Despite the initial effectiveness of treatment in horses and humans, AF-induced atrial remodeling compromises its long-term success. Observational studies have suggested that metformin may reduce the risk of AF, but its effects on progressive AF-induced atrial remodeling have yet to be evaluated in a high-fidelity large animal model. Unassigned: Here, we used a longitudinal horse model of tachypacing-induced self-sustained AF to c...
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...
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...
Liposomal bupivacaine caudal epidural in horses results in adverse effects without analgesia. To evaluate the analgesic properties and adverse effects of liposomal bupivacaine administered via caudal epidural in horses. Methods: Pharmacodynamic study. Methods: A total of 10 healthy adult horses. Methods: Liposomal bupivacaine (10 mL; 1.3%) was administered into the caudal epidural space via an indwelling epidural catheter inserted to a length of 15 cm. Mechanical nociceptive threshold (MNT) testing with pressure algometry was used to measure analgesia at four anatomic locations for 72 h following injection. Physical examinations (including rectal temperature, heart rate, respirat...
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...
Effects of clodronate disodium on markers of inflammation and cartilage metabolism in juvenile horses challenged with intra-articular lipopolysaccharide. Perceived chondroprotective and anti-inflammatory benefits of bisphosphonates in the juvenile horse has led to extra-label use without supportive data regarding intra-articular effects on cartilage metabolism and inflammation. Thirty-two yearling Quarter Horses were stratified into 4 treatment groups by age (500 ± 13 d), BW (336 ± 26 kg), sex (n = 16 female; n = 16 male) and initial bone optical density for a 140-d study. The study consisted of two exercise phases: Phase 1 (d 0-84) emulated sales preparation and Phase 2 (d 99-140) mimicked early exercise training. Horses we...
Inhibition of interleukin-1 receptor-associated kinase (IRAK)-4 provides partial rescue of interleukin-1 beta induced functional and gene expression changes in equine tenocytes. Interleukin 1 beta (IL-1β) is upregulated following a tendon injury and in vitro studies have shown that it leads to numerous negative effects on tendon cell function and gene expression. IL-1β activates nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and we hypothesised that inhibiting NF-κB activation would mediate the negative effects of IL-1β on equine tendon cells in 3-dimensional (3D) cultures. Results: Here, we tested three inhibitors of NF-κB signalling (Bortezomib, BAY11-7082 and Wedelolactone) along withTJ-M2010-5, an inhibitor of MyD88, which is a critic...
Metabolism, pharmacokinetics, and bioavailability of cannabigerol in horses following intravenous and oral administration with micellar and oil formulations. Cannabigerol (CBG) is a non-psychoactive cannabinoid with growing interest in veterinary medicine; however, its pharmacokinetic profile in horses remains unknown. Understanding its absorption, distribution, metabolism, and elimination is essential to optimizing dosing strategies and evaluating its potential for clinical use in equine patients. Unassigned: A prospective crossover study was conducted in eight healthy adult horses to assess the metabolism and the pharmacokinetics after intravenous (IV) administration at 1 mg/kg and oral administrations at 10 mg/kg with two formulations (mice...