The topic of medication in horses encompasses the study and application of pharmaceutical substances used to treat, manage, or prevent diseases and conditions in equine patients. This field involves understanding the pharmacokinetics and pharmacodynamics of various drugs, including their absorption, distribution, metabolism, and excretion in horses. Medications commonly administered to horses include non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, anthelmintics, and sedatives. The appropriate use of these medications is critical for ensuring therapeutic efficacy and minimizing adverse effects. Research in this area focuses on dosage optimization, drug interactions, resistance development, and withdrawal times to ensure both the health of the horse and compliance with regulatory standards. This page aggregates peer-reviewed studies and scholarly articles that explore the pharmacological aspects, clinical applications, and regulatory considerations of equine medications.
Nannarone S, Gialletti R, Veschini I, Bufalari A, Moriconi F.Alpha-2 agonists are synthetic drugs which cause sedation, analgesia and myorelaxation due to their interaction with alpha-2 adrenoreceptors, widely distributed throughout bodily systems. Because of these actions such drugs are generally used in veterinary practice: to tranquilize animals (pharmacologic restraint) for the safety of both veterinar-ians and cooperators. Such properties facilitate diagnostic examinations or minimally in-vasive and poorly painful surgical procedures, as well as limiting stress factors to the patients. The aim of this study is to find out the minor dosage able to m...
Fuller MC, Abutarbush SM.A 10-year-old gelding was presented with a tongue that had swelled immediately after oral administration of oxfendazole, using an udder infusion cannula. The tongue appeared to have been punctured inadvertently. The horse recovered after treatment with intravenous fluid, antibiotics, and anti-inflammatory drugs. Administering oral medication by this method should be discouraged. Un cheval hongre âgé de 10 ans a été présenté avec une langue devenue tuméfiée immédiatement après l’administration orale d’oxfendazole à l’aide d’une canule à infusion du pis. La langue semblait a...
Gasthuys F, Pockelé K, Vervaet C, Weyenberg W, De Prijck K, Pille F, Vlaminck L, Nelis H, Remon JP.The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion met...
Bliss G.The Department of Pharmacology at the North Carolina State University College of Veterinary Medicine is currently conducting stability studies of oral suspensions of pergolide for the treatment of Cushing's disease. While those results are not available at this time, this paper summarizes the results of a literature search on possible clinical treatments for equine Cushing's and is intended to provide insight into the pathophysiology of the disease. Pharmacological options for treatment of equine Cushing's are discussed.
Richardson DW, Loinaz R.There is an enormous volume of published material about most of the agents used to treat or prevent arthritis in horses. Unfortunately, most of the claims made by nearly all purveyors of arthritis medications in such media are largely unsubstantiated. In addition, the quality of the available information is highly inconsistent, making evidence-based recommendations difficult. This article concentrates on injectable polysulfated glycosaminoglycan, injectable hyaluronan, and the common oral "nutraceuticals".
Olsén L, Bondesson U, Broström H, Tjälve H, Ingvast-Larsson C.The pharmacokinetics of the histamine H(1)-antagonist cetirizine and its effect on histamine-induced cutaneous wheal formation were studied in six healthy horses following repeated oral administration. After three consecutive administrations of cetirizine (0.2 mg/kg body weight, bw) every 12h, the trough plasma concentration of cetirizine was 16+/-4 ng/mL (mean+/-SD) and the wheal formation was inhibited by 45+/-23%. After four additional administrations of cetirizine (0.4 mg/kg bw) every 12 h, the trough plasma concentration was 48+/-15 ng/mL and the wheal formation was inhibited by 68+/-11%....
White G, McClure SR, Sifferman R, Holste JE, Fleishman C, Murray MJ, Cramer LG.To determine the effects of 8 days of light to heavy exercise on gastric ulcer development in horses and determine the efficacy of omeprazole paste in preventing gastric ulceration. Methods: Randomized, controlled, multicenter clinical trial. Methods: 102 horses with normal-appearing gastric mucosa on endoscopic examination that were in light to heavy training. Methods: Horses at 4 trial locations were allocated into replicates and sham dosed orally (empty syringe) or treated with a paste formulation of omeprazole (1 mg/kg [0.45 mg/ lb], PO) once daily for 8 days. Training regimens varied amon...
Camargo FC, Robinson NE, Berney C, Eberhart S, Baker S, Detolve P, Derksen FJ, Lehner AF, Hughes C, Tobin T.The bronchodilator effects of trimetoquinol (TMQ) have been studied when administered i.v. or intratracheally, but not in an aerosolised form. Objective: To define the relationship between the therapeutic and adverse responses (therapeutic index) of TMQ when administered as an aerosol or by the oral route. Methods: Increasing doses of TMQ were administered to horses with heaves as an aerosol and by the oral route. Dose ranged 100-1000 microg/horse for aerosolised TMQ and from 6-60 microg/kg bwt for the oral route. Airway and cardiac effects were assessed by measurement of maximal change in ple...
Di Concetto S, Michael Archer R, Sigurdsson SF, Clarke K.A pony undergoing elective castration accidentally received an overdose of IV detomidine (200 microg kg(-1)) before anaesthesia was induced with ketamine and midazolam. A further 100 microg kg(-1) IV dose of detomidine was administered during anaesthesia. The mistake was recognized only when the animal failed to recover from anaesthesia in the expected time. The overdose (300 microg kg(-1) in total) was treated successfully with atipamezole, initially given IV and subsequently IM and titrated to effect to a total dose of 1100 microg kg(-1). The pony regained the standing position. A further in...
Aleman M, Gray LC, Williams DC, Holliday TA, Madigan JE, LeCouteur RA, Magdesian KG.Epilepsy is relatively uncommon in horses compared with other species and limited information is available. Objective: The objectives of the study were to describe the age of onset, clinical signs, clinicopathologic data, electroeticephalographic findings, treatment, and outcome, including long-term prognosis in Arabian foals with idiopathic epilepsy. Methods: Twenty-two foals were included in the study. Methods: Medical records from 1985 to 2005 were reviewed. Results: The age of onset of affected foals ranged from 2 days to 6 months. Seizures were characterized by generalized tonic and cloni...
Betbeze CM, Wu CC, Krohne SG, Stiles J.To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis. Methods: Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses. Methods: Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined. Results: For all 17 fungal isolat...
Nogueira SA, Torres SM, Malone ED, Diaz SF, Jessen C, Gilbert S.Imiquimod is an immune response modifier with potent antiviral and antitumour activity. The objective of this pilot study was to evaluate the efficacy of an imiquimod 5% cream (Aldaratrade mark: 3M, Saint Paul, MN, USA) as a topical treatment for equine sarcoids. Fifteen horses with a total of 19 tumours were enrolled, including mixed (7), fibroblastic (5), flat (3), verrucous (2), and nodular (2) types. Baseline data included history, physical examination, tumour location, measurement and digital photography. Imiquimod was applied by the owners three times a week until complete resolution of ...
Bentz BG, Maxwell LK, Erkert RS, Royer CM, Davis MS, MacAllister CG, Clarke CR.The purpose of the study reported here was to describe the bioavailability and pharmacokinetics of acyclovir after intravenous and oral administration to horses. Six healthy adult horses were used in a randomized cross-over study with a 3 x 3 Latin square design. Three treatments were administered to each horse: 10 mg of injectable acyclovir/kg of body weight in 1 L of normal saline delivered as an infusion over 15 minutes; 10 mg of acyclovir/kg in tablets by nasogastric intubation; and 20 mg of acyclovir/kg in tablets by nasogastric intubation. A 2-week washout period was provided between eac...
Rubio-Martínez LM, Cruz AM.Regional limb perfusion involves administration of an antimicrobial solution into the vasculature of a selected portion of the limb that has been isolated from the systemic circulation by controlled application of a tourniquet. The technique provides high antimicrobial concentrations in the region of interest and greatly contributes to the elimination of infection.
Rayner SG, Van Zyl N.To assess the effectiveness of topical mitomycin C application as an alternative adjunctive therapy to CO2 laser ablation in the treatment of equine ocular squamous cell carcinoma. Methods: A retrospective clinical study of eight client owned horses in which 10 affected eyes were treated for ocular squamous cell carcinoma over a 17 month period. (March 2003 to August 2004). Methods: Each horse was given a general anaesthetic to allow CO2 laser ablation of the lesion(s). Mitomycin C at a concentration of 0.4 mg/mL was then applied intraoperatively to the affected areas for 1 or 5 minutes. Posto...
Morsy TA, Salem HS, Haridy FM, Rifaat MM, Abo-Zenadah NY, Adel el-Kadi M.To continue the study on fascioliasis in Tamyia Center, some farm animals were investigated for natural infection with Fasciola species by stool examination. The results showed 40% infection in sheep, 20% in buffalos, 6.7% in donkeys and zero% in horses. The overall percentage of infection was 25.5. The sheep (total dose 1800mg) and the donkey (total dose (4500 mg.) were successfully treated with Mirazid. On the other hand, one buffalo was successfully treated by a total dose 7500mg, the seconds one did not cured, but the eggs deposited per gm markedly decreased.
Bishop WJ.GG is a useful sedative and anaesthetic agent in horses. Used
alone, or in conjunction with barbiturates, it produces a un-
iformly smooth recovery from anaesthesia.
The need to infuse large volumes to obtain the desired effect is
a disadvantage ofthis agent. Few critical studies have been made
on the short and long term effects of administration of GG to
horses. Its pharmacology and clinical use are described and
indicate that it is a safe and useful drug.
Neudeck S, Twele L, Kopp V, Kästner S.The aim was to determine the effects of vatinoxan on dexmedetomidine plasma concentrations and effects on cardiovascular and intestinal tissue pharmacodynamics. In a prospective randomized study, six horses were premedicated intravenously with dexmedetomidine 3.5 µg kg followed by a constant-rate infusion of 7 µg kg h (group DEX) and six horses with dexmedetomidine of the same dose (bolus and constant-rate infusion) combined with vatinoxan 130 µg kg followed by 40 µg kg h (group VAT). Anaesthesia was induced with ketamine and diazepam and maintained with isoflurane. Venous bloo...
Todhunter RJ, Stick JA, Trotter GW, Boles C.Esophageal strictures developed in 7 horses that were treated for esophageal obstruction. A soft diet was fed to all horses, with intermittent nasogastric tube feeding in one, and medication included nonsteroidal anti-inflammatory drugs. Maximal reduction in esophageal lumen diameter was evident by 30 days following circumferential esophageal ulceration, after which lumen diameter increased rapidly. Five horses were clinically normal by 60 days after the esophageal injury. Two horses were euthanatized at the owner's request, 16 and 17 days after the original insult.
Olsén L, Bondesson U, Broström H, Tjälve H, Ingvast-Larsson C.The pharmacokinetics of the histamine H(1)-antagonist cetirizine and its effect on histamine-induced cutaneous wheal formation were studied in six healthy horses following repeated oral administration. After three consecutive administrations of cetirizine (0.2 mg/kg body weight, bw) every 12h, the trough plasma concentration of cetirizine was 16+/-4 ng/mL (mean+/-SD) and the wheal formation was inhibited by 45+/-23%. After four additional administrations of cetirizine (0.4 mg/kg bw) every 12 h, the trough plasma concentration was 48+/-15 ng/mL and the wheal formation was inhibited by 68+/-11%....
Pearson W.Standardbred trainers from 1 racetrack and 7 off-track training facilities were surveyed to determine the most common drugs, and prevalence of concurrent herb administration. Furosemide (on-track) and anti-inflammatory drugs (off-track) were the most common drugs administered. Among horses on-track, 9.8% received herbs compared with 13.8% off-track horses; 67% and 58% of these horses, respectively, received concurrent drugs. Les soigneurs de Standardbreds de 1 piste de course et de 7 installations d’entraînement hors piste ont été interrogés afin de déterminer les médicaments les plus...
Knych HK, Stanley SD, Arthur RM, McKemie DS.The use of anti-ulcer medications, such as cimetidine, ranitidine, and omeprazole, is common in performance horses. The use of these drugs is regulated in performance horses, and as such a withdrawal time is necessary prior to competition to avoid a medication violation. To the authors' knowledge, there are no reports in the literature describing repeated oral administrations of these drugs in the horse to determine a regulatory threshold and related withdrawal time recommendations. Therefore, the objective of the current study was to describe the disposition and elimination pharmacokinetics o...