Oral administration in horses refers to the delivery of medications, supplements, or nutrients via the mouth. This method is commonly used in equine veterinary medicine for its practicality and ease of use. Oral formulations can include powders, pastes, or liquids, which are designed to be palatable and easily ingested by horses. The effectiveness of oral administration depends on factors such as the horse's digestive physiology, the formulation of the product, and the consistency with which it is administered. This page compiles peer-reviewed research studies and scholarly articles that explore the techniques, efficacy, and considerations of oral administration in equine care.
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Perwad Z, Graiban FM, Caveney MR, Sayed R, Kadry AM.According to previous research, aminorex is the major metabolite of levamisole; however, in the screening of levamisole-positive racehorse urine and plasma samples, aminorex could only be detected in trace amounts or not at all. In forensic laboratories, hydroxy levamisole and its phase II conjugates make it easier to confirm levamisole misuse and to differentiate between the abuse of levamisole and aminorex. This study aimed to identify the major levamisole metabolites that can be detected along with the parent drug. Methods: The study describes levamisole and its metabolites in thoroughbred ...
Turner SE, Knych HK, Adams AA.To determine the pharmacokinetics, bioavailability, and pharmacological effects of cannabidiol (CBD) in senior horses. Methods: 8 university-owned senior horses. Methods: In this randomized, crossover study, horses were assigned to receive either a single oral dose of 2 mg/kg CBD in oil or a single IV dose of 0.1 mg/kg CBD in DMSO between August 10 and September 4, 2020. Blood samples were collected before and then 0.5, 1, 4, 8, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, and 264 hours after CBD administration. Serum biochemical analyses and CBCs were performed. Plasma concentrations of CBD ...
Cota LO, Júnior OS, Oliveira APL, Paz CFR, Maróstica TP, Duarte PC, Leme FOP, Faleiros RR.Systemic inflammatory response syndrome (SIRS) is a common condition in horses with gastrointestinal disorders. If not prevented or controlled, SIRS promotes multiple organ dysfunctions that may culminate in serious disabilities or even death. The objective of this study was to evaluate the effects of Lithothamnion supplementation on systemic inflammatory response and organ function variables in horses undergoing oligofructose overload (OFO) intake. Twelve healthy horses were randomly divided into control and treated groups. The treated group received Lithothamnion (100 mg/kg bw PO BID) for 7 ...
Kimura S, McCoy AM, Boothe DM, Wooldridge AA, Graff E, Hammack SM, Cresci L, Hofmeister E, Lascola KM.To describe misoprostol pharmacokinetics and anti-inflammatory efficacy when administered orally or per rectum in endotoxin-challenged horses. Methods: 6 healthy geldings. Methods: A randomized 3-treatment crossover design was performed with a minimum washout period of 28 days between treatment arms. Prior to endotoxin challenge (lipopolysaccharide, 30 ng/kg IV over 30 minutes), horses received misoprostol (5 µg/kg once) per os (M-PO) or per rectum (M-PR) or water as control (CON). Clinical parameters were evaluated and blood samples obtained to measure plasma misoprostol free acid concentrat...
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Koshy SA.It is important to remember that performance-enhancing agents such as non-peptide growth hormone secretagogues present a significant risk of abuse. Ibutamoren (MK-0677) is a potent, long-acting, selective non-peptide growth hormone secretagogue that can be taken orally. Methods: This study examines ibutamoren and its metabolites in thoroughbred horses after oral administration. Liquid chromatography/high-resolution mass spectrometry was used to determine the probable structures of the detected metabolites. Results: In this study, 22 metabolites of ibutamoren were identified (17 phase I and 5 p...
Yamada ALM, do Prado Vendruscolo C, Marsiglia MF, Sotelo EDP, Agreste FR, Seidel SRT, Fülber J, Baccarin RYA, da Silva LCLC.Combined chondroitin sulfate (CS) and glucosamine (GlcN) has been widely used in oral formulations to prevent and treat osteoarthritis. CS is effective for controlling pain in osteoarthritic patients, whereas GlcN can stimulate glycosaminoglycan synthesis, thus reducing extracellular matrix degradation. Although several studies have been published on this topic, the effectiveness of treatment with oral CS and GlcN remains uncertain. The objective of this study was to analyze the progression of experimentally induced osteoarthritis in horses and verify the effectiveness of an oral compound base...
Seabaugh KA, Barrett MF, Rao S, McIlwraith CW, Frisbie DD.Osteoarthritis (OA) is a common problem in horses. Several oral supplements have been proposed as treatments for horses with OA. The object of this study was to evaluate the use of the oil extract from the seeds of (BO) for the treatment of experimentally induced OA in horses. OA was induced in 16, 2-5 year old horses in one middle carpal joint on Day 0; the other limb underwent a sham operation. Once daily oral treatment with BO or placebo was initiated on Day 0 and continued to Day 70. All horses were exercised 5 days a week starting on Day 14 through Day 70. The horses were evaluated every...
Hoffmann SL, Seminoff K, McKemie DS, Kass PH, Knych HK.Grapiprant is a prostaglandin E2 receptor antagonist that has been found to be an effective anti-inflammatory in dogs and that is devoid of some of the adverse effects associated with traditional NSAIDs that elicit their effects through inhibition of PGE2 production. Previously published reports have described the pharmacokinetics of this drug in horses when administered at 2 mg/kg; however, pharmacodynamic effects in this species have yet to be described. The objective of the current study was to describe the pharmacokinetics and pharmacodynamics of grapiprant at a higher dose. Eight horses...
Knych HK, Stucker K, Gretler SR, Kass PH, McKemie DS.In humans, codeine is a commonly prescribed analgesic that produces its therapeutic effect largely through metabolism to morphine. In some species, analgesic effects of morphine have also been attributed to the morphine-6-glucuronide (M6G) metabolite. Although an effective analgesic, administration of morphine to horses produces dose-dependent neuroexcitation at therapeutic doses. Oral administration of codeine at a dose of 0.6 mg/kg has been shown to generate morphine and M6G concentrations comparable to that observed following administration of clinically effective doses of morphine, witho...
Thieulent CJ, Sutton G, Toquet MP, Fremaux S, Hue E, Fortier C, Pléau A, Deslis A, Abrioux S, Guitton E, Pronost S, Paillot R.Equid alphaherpesvirus-1 (EHV-1) is one of the main pathogens in horses, responsible for respiratory diseases, ocular diseases, abortions, neonatal foal death and neurological complications such as equine herpesvirus myeloencephalopathy (EHM). Current vaccines reduce the excretion and dissemination of the virus and, therefore, the extent of an epizooty. While their efficacy against EHV-1-induced abortion in pregnant mares and the decreased occurrence of an abortion storm in the field have been reported, their potential efficacy against the neurological form of disease remains undocumented. No ...
Haughan JE, Missanelli JR, You Y, Stefanovski D, Soma LR, Robinson MA.Glaucine, an aporphine alkaloid with anti-tussive, anti-inflammatory, and anti-nociceptive properties, has been identified in post-race samples from racehorses. To investigate pharmacokinetics of glaucine in horses, a three-way crossover study of intravenous and oral glaucine (0.1 mg/kg) and orally administered tulip poplar shavings (50 g shavings = 0.001 mg/kg glaucine) was performed in six horses. A two-compartment model best described IV administration with alpha ( ) and beta ( ) half-life lives of 0.3 (0.1-0.7) and 3.1 (2.4-7.8) h, respectively. The area under the curve ( ) was ...
Cutler C, Viljanto M, Taylor P, Habershon-Butcher J, Van Eenoo P.Ibutamoren mesylate, or MK-0677, is an orally active, nonpeptide growth hormone secretagogue that has been developed to stimulate excretion of endogenous growth hormone. It has been evaluated for the treatment of a range of clinical conditions but is not available therapeutically. Nonetheless, MK-0677 is widely available to purchase online, sold as 'supplement' products. The mode of action and relative ease of purchase make MK-0677 a potential threat with regard to sports doping. The aim of this study was to investigate the metabolism of MK0677 in the horse following in vitro incubation and or...
Yocom AF, O'Fallon ES, Gustafson DL, Contino EK.Cannabidiol (CBD) products are widely marketed to horse owners, trainers, and veterinarians and are readily available to the consumer despite minimal pharmacokinetic or safety data being available. The objectives of this study were to determine the plasma pharmacokinetics, short-term safety, and synovial fluid levels of CBD following oral administration in horses. A prospective, randomized, controlled study design was used. Twelve horses were administered sunflower lecithin oil-based CBD at either 1 mg/kg (Group 1) or 3 mg/kg (Group 2) for a 24-hour pharmacokinetic study. Horses then received ...
Chapuis RJJ, Becker AAMJ, Dowling PM, Weese JS.Antimicrobial-associated diarrhoea is a common adverse effect of antimicrobial treatment in horses and has been reported following the administration of oral doxycycline. The administration of antimicrobials has also been associated with changes in the equine intestinal microbiota diversity yet has not been explored under doxycycline treatment. Objective: To describe the dynamics of the faecal microbial diversity following a 5-day oral administration of doxycycline in healthy horses with Streptococcus zooepidemicus infected tissue chambers. Methods: Experimental prospective cohort study in a s...
Nagae M, Nishio T, Ohnuki K, Shimizu K.Placenta extract is used as an ingredient in ointments for treating dermatological diseases, skin dryness, and for skin beautification. However, the clinical effects of the equine placenta on humans and the underlying mechanism of action are unclear. This randomized, controlled, double-blind study aimed to clinically evaluate the effect of oral intake of equine placental extract on human skin quality. Methods: Healthy women volunteers between the ages of 30 and 59 years (n = 29) were randomly assigned to receive 220 mg of equine placental extract-placebo orally, once daily for 4 weeks....
Gough S, Hallowell G, Rendle D.Equine glandular gastric disease (EGGD) is common in domesticated horses and can be challenging to treat. Oral omeprazole (ORLO) is used widely but the clinical response is frequently poor. Objective: To compare rates of EGGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). Methods: Retrospective clinical study. Methods: The case records and gastroscopy images of horses presenting to masked for peer review over a 12-month period were reviewed, with images blindly assessed by one of the authors. Treatment responses to 4 mg/kg LAIO administered eve...
Gold JR, Grubb TL, Cox S, Malavasi L, Villarino NL.The repeated administration of high doses of gabapentin may provide better analgesia in horses than current clinical protocols. Objective: Administration of gabapentin at 40 and 120 mg/kg PO q 12 h for 14 days will not alter serum biochemistry findings or cause adverse effects. Our objectives were to evaluate the effect of gabapentin on serum biochemistry, physical examination, and plasma pharmacokinetics of gabapentin. Methods: Six healthy adult mares. Methods: Horses received 40 and 120 mg/kg of gabapentin orally q 12 h for 14 days. Horses were examined and scored for ataxia and ...
Redmond JS, Stang BV, Schlipf JW, Christensen JM.Diphenhydramine is an H1 receptor antagonist used to control urticaria and other allergic signs caused by type I hypersensitivity reactions in horses (Equus caballus). Limited studies have been conducted on pharmacokinetics of this drug in horses, with no studies involving oral formulations. Our study investigated pharmacokinetics of an oral diphenhydramine formulation compared to intravenous administration in non-fasted adult horses. Six healthy horses underwent a single administration of three different doses of diphenhydramine (1 mg/kg intravenously, 1 mg/kg intragastrically, and 5 mg/kg...
Williams MR, Holbrook TC, Maxwell L, Croft CH, Ientile MM, Cliburn K.Cannabidiol (CBD) products have gained popularity among horse owners despite limited evidence regarding pharmacokinetics. The purpose of this study was to describe the pharmacokinetic profile of multiple doses of an orally administered cannabidiol product formulated specifically for horses. A randomized 2-way crossover design was used. Seven horses received 0.35 or 2.0 mg/kg CBD per os every 24 hours for 7 total doses, separated by a 2-week washout. Plasma CBD and delta-9-tetrahydrocannabinol (THC) were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) daily through da...
Luethy D, Robinson MA, Stefanovski D, Haughan J, Torcivia C, Kowalski A, Ford M, You Y, Missanelli J, Slack J.Cardiac drugs with defined pharmacological parameters in horses are limited. The objective of this study was to characterize the pharmacokinetic properties and cardiovascular effects of intravenous and oral metoprolol tartrate (MET) in horses. In a 2-period randomized cross-over design, MET was administered IV (0.04 mg/kg) and PO (6 mg/kg) once to six healthy adult horses. Horses were monitored via continuous telemetry and non-invasive blood pressure (NIBP). Blood samples were serially collected for 72 h post-administration, and concentrations were determined by LC-MS/MS. Pharmacokinetics w...
Houck EL, Papich MG, Delk KW.Southern white rhinoceros (Ceratotherium simum simum) frequently develop painful conditions, such as traumatic injuries or osteoarthritis, necessitating the administration of pain-relieving medications. One of the preferred treatments is the nonsteroidal anti-inflammatory drug phenylbutazone because of the availability of oral formulations and the familiarity of its use in horses. For the main study, a single oral dose of phenylbutazone at 2 mg/kg was administered to healthy adult rhinoceros (n = 33) housed at six North American zoological institutions. Each rhinoceros had up to four blood ...
Thomson P, Toro J, Lara F, Hernández D, Aros K, Valenzuela-Lopez N.We present the first case of rhinopharyngitis due to Aspergillus fumigatus in a purebred Chilean horse. Clinically, manifested mucopurulent discharge from both nostrils, inflammation of the nasal, ocular, and ear mucosa; associated with decay and hyporexia. Based on the clinical signs and analysis of the mycological and molecular transtracheal aspirate sample, the present case was diagnosed as Aspergillus fumigatus rhinopharyngitis. After the antifungal susceptibility test, oral itraconazole treatment was maintained for 45 days, showing no clinical sign.
Waitt Wolker LH, Veltri CA, Pearman K, Lozoya M, Norris JW.This study aimed to investigate pharmacokinetics of fluoxetine in horses and validate a method for liquid chromatography mass spectrometry analysis of serum levels. Fluoxetine pharmacokinetics were determined using 10 healthy, adult horses. Fluoxetine pharmacokinetics following a single oral dose (0.25 mg/kg) were determined using blood samples collected prior to and at several time points over 7 days following administration. Serum concentrations of fluoxetine and its bioactive metabolite norfluoxetine were measured using liquid chromatography coupled to an accurate mass/high-resolution ma...
Paine SW, Aldurdunji M, Garth-Greeves A, Muir T, Hincks PR.Hydroxyzine and cetirizine are first- and second-generation oral antihistamine drugs, respectively, used to treat allergic reactions in horses. Cetirizine is also a metabolite of hydroxyzine, which may lead to complexities in regulating their use in equine sporting events. The aim of the research was to be able to provide detection times (DT) from pharmacokinetic studies in thoroughbred horses to better inform trainers, and their veterinary surgeons, prescribing these substances for treatment of Thoroughbred racehorses. Six and two horses were given 9 repeated administrations of hydroxyzine HC...
McReynolds CB, Yang J, Guedes A, Morisseau C, Garcia R, Knych H, Tearney C, Hamamoto B, Hwang SH, Wagner K, Hammock BD.There are few novel therapeutic options available for companion animals, and medications rely heavily on repurposed drugs developed for other species. Considering the diversity of species and breeds in companion animal medicine, comprehensive PK exposures in the companion animal patient is often lacking. The purpose of this paper was to assess the pharmacokinetics after oral and intravenous dosing in domesticated animal species (dogs, cats, and horses) of a novel soluble epoxide hydrolase inhibitor, EC1728, being developed for the treatment of pain in animals. Results: Intravenous and oral adm...
Sasaki N, Nishi Y, Fujiwara Y, Takeyama T, Kumagai H, Senarathna S, Ushiya S, Tokuyama T, Tokuyama T, Tokuyama T, Mii T, Ayaki S, Matsuno K....Gastric ulcers cause appetite loss, poor body condition, and colic in horses. This study investigated the protective effect of a rice fermented extract on the gastric mucosa in 17 healthy Thoroughbreds. For one month, horses in the rice fermented extract (nine horses) and control (eight horses) groups were orally administered a rice fermented extract (100%; 0.2 ml/kg, SID) and tap water (0.2 ml/kg), respectively. Gastric endoscopic images were obtained before and one month after rice fermented extract administration. The gastric ulcer score was lower after administration (median, 1; maximum, 2...
Chapuis RJJ, Smith JS, Uehlinger FD, Meachem M, Johnson R, Dowling PM.The objectives of this study were to investigate the pharmacokinetics (PK), pharmacodynamics (PD), and the efficacy of oral administration of doxycycline (DXC) in horses with Streptococcus zooepidemicus tissue infections. Tissue chambers (TC) were implanted subcutaneously in the cervical region of 7 horses and inoculated with a single S. zooepidemicus isolate with a minimum inhibitory concentration (MIC) of 0.25 µg/ml, determined by agar dilution. Doxycycline hyclate (10 mg/kg, orally, q 12 h, for 5 days) mixed with poloxamer gel was started following inoculation. The TC fluid was samp...
Wallace GE, McKaba VF, Reinhart JM, Li Z, Austin S, Fries RC.Large vessel and microvascular thrombi are common complications in systemically ill horses contributing to patient morbidity and mortality. Apixaban, an oral factor Xa inhibitor, shows excellent efficacy against stroke and deep vein thrombosis in humans. The purpose of this study was to determine serum apixaban concentrations and anti-factor Xa activity in horses after orally administered apixaban. Five horses received a single dose of intravenous (0.09 mg/kg) and oral (1 mg/kg) apixaban in a cross-over design. Serum apixaban concentrations and anti-Xa activity were measured serially via liq...
Knych HK, McKemie DS, Kanarr KL, White SD.To characterize the pharmacokinetics of mycophenolate mofetil (MMF) following single-dose IV or PO administration, characterize the pharmacokinetics of MMF following long-term PO administration, and describe the clinicopathologic effects of long-term MMF administration in horses. Methods: 12 healthy adult horses. Methods: In phase 1, 6 horses received a single IV (2.5 mg/kg) or PO (5 mg/kg) dose of MMF in a randomized balanced crossover assessment (≥ 2-week interval between administrations). In phase 2, 6 other horses received MMF for 60 days (5 mg/kg, PO, q 24 h for 30 days and then 5 mg/kg...
Picetti TS, Soveral LF, Miotto R, Erpen LMS, Kreutz Y, Guizzo JA, Frandoloso R, Kreutz LC.Immune-modulating molecules mainly act on innate immune cells, which are central to early defense against invading pathogens and contribute to developing adaptive immunity. Yeast-extracted β-glucan, a model immune-modulating molecule, is widely used in several animal species; however, its effect on horse immune parameters has not been thoroughly investigated yet. This study aimed to evaluate the effects of orally administered β-glucan on selected innate immune parameters in horses. Methods: Eighteen thoroughbred horses were assigned equally into three groups as follows: One control group (no...
Pérez R, Cabezas I, Sutra JF, Galtier P, Alvinerie M.A study was undertaken to evaluate and compare faecal excretion of moxidectin and ivermectin in horses after oral administration of commercially available preparations. Ten clinically healthy adult horses, weighing 390-446 kg body weight (b.w.), were allocated to two experimental groups. Group I was treated with an oral gel formulation of moxidectin at the manufacturer's recommended therapeutic dose of 0.4 mg/kg b.w. Group II was treated with an oral paste formulation of ivermectin at the recommended dose of 0.2 mg/kg b.w. Faecal samples were collected at different times between 1 and 75 days ...
Gokbulut C, Nolan AM, McKellar QA.The present study was carried out to investigate whether the pharmacokinetics of avermectins or a milbemycin could explain their known or predicted efficacy in the horse. The avermectins, ivermectin (IVM) and doramectin (DRM), and the milbemycin, moxidectin (MXD), were each administered orally to horses at 200 microg/kg bwt. Blood and faecal samples were collected at predetermined times over 80 days (197 days for MXD) and 30 days, respectively, and plasma pharmacokinetics and faecal excretion determined. Maximum plasma concentrations (Cmax) (IVM: 21.4 ng/ml; DRM: 21.3 ng/ml; MXD: 30.1 ng/ml) w...
Tobin T, Chay S, Kamerling S, Woods WE, Weckman TJ, Blake JW, Lees P.Phenylbutazone is an acidic, lipophilic, non-steroidal anti-inflammatory drug (NSAID). It is extensively metabolized in the horse. The metabolites so far identified, oxyphenbutazone, gamma-hydroxyoxyphenbutazone, account for some 25-30% of administered dose over 24 h. The plasma half-life of phenylbutazone and termination of its pharmacological action are determined primarily by its rate of hepatic metabolism. Phenylbutazone acts by inhibiting the cyclooxygenase enzyme system, which is responsible for synthesis of prostanoids such as PGE2. It appears to act on prostaglandin-H synthase and pros...
Gustafsson A, Båverud V, Franklin A, Gunnarsson A, Ogren G, Ingvast-Larsson C.Six healthy adult horses were given repeated administrations of trimethoprim/ sulfadiazine (TMP/SDZ) intravenously (i.v.) (2.5 mg/kg TMP and 12.5 mg/kg SDZ) and orally (p.o.) as a paste (5 mg/kg TMP and 25 mg/kg SDZ). Both formulations were given twice daily for 5 days, with a 3-week interval between i.v. and oral administration. The influence of the drug combination on the intestinal microflora was examined and the plasma concentrations, pharmacokinetic parameters and plasma protein binding were determined. There were no major changes in the bacterial intestinal flora and no clinical evidence...
Kivett L, Taintor J, Wright J.Simultaneous administration of a nonselective COX inhibitor and a COX-2 specific NSAID has not been previously reported in horses. The goal of this study was to determine the safety of a 10-day dosage regimen of phenylbutazone and firocoxib, both at their standard dosages, in horses. Six horses were administered 2.2 mg/kg of phenylbutazone and 0.1 mg/kg of firocoxib by mouth, daily for 10 days. Horses were assessed daily for changes in behavior, appetite, fecal consistency, signs of abdominal pain, and oral mucous membrane ulceration. Horses were assessed prior to and on the last day of treatm...
Lester GD, Smith RL, Robertson ID.To compare the effects of oral administration of omeprazole and ranitidine on gastric squamous ulceration in Thoroughbreds in race training. Methods: Modified crossover study. Methods: 60 Thoroughbreds in race training with gastric squamous mucosal ulceration. Methods: Horses were randomly allocated into 3 groups. Group 1 received no treatment for 28 days followed by administration of omeprazole (4 mg/kg [1.8 mg/lb], PO, once daily) for 28 days; group 2 received omeprazole (4 mg/kg, PO, once daily) for 28 days followed by no treatment for 28 days; and group 3 received ranitidine (6.6 mg/kg [3....
Couëtil LL, Chilcoat CD, DeNicola DB, Clark SP, Glickman NW, Glickman LT.To determine whether administration of glucocorticoids provides additional benefits to environmental management of horses with recurrent airway obstruction (RAO). Methods: 28 horses with RAO. Methods: Horses were classified as having mild, moderate, or severe RAO. Within each category, horses were randomly assigned to receive inhaled fluticasone propionate, inhaled control substance, or oral administration of prednisone. During the 4-week study, horses were maintained outdoors and fed a pelleted feed. Clinical scores, pulmonary function, results of cytologic examination of bronchoalveolar lava...
Turner S, Knych HK, Adams AA.Cannabidiol (CBD) has potential to reduce pain and inflammation in humans leading to the interest of use in equine. The purpose of this study was to determine the effects of CBD on immune function by measuring inflammatory cytokines and antibody responses to vaccination, as well as other health parameters in senior horses. Horses were orally-dosed with CBD (2 mg/kg: 13 horses) or control (soy oil: 14 horses) daily for 90 days, from July 2021 to November 2021. Peripheral blood samples were collected on days 0, 30, 60, and 90 before administering treatments. On day 90 all horses were kept on tr...
Ensink JM, Klein WR, Mevius DJ, Klarenbeek A, Vulto AG.The pharmacokinetics of ampicillin and amoxicillin following intravenous administration at a dose rate of 15 and 10 mg/kg respectively were studied in four healthy adult horses. Pharmacokinetics of pivampicillin and amoxicillin were studied after oral administration to four healthy adult horses. Pivampicillin, a prodrug of ampicillin, was administered orally to starved and fed horses at a dose rate of 19.9 mg/kg, which is equivalent on a molecular basis to 15 mg/kg ampicillin. Amoxicillin was administered orally to starved horses only, at a dose rate of 20 mg/kg. Ampicillin and amoxicillin con...
Letendre LT, Tessman RK, McClure SR, Kvaternick VJ, Fischer JB, Hanson PD.To determine pharmacokinetic parameters and variables, firocoxib concentrations in urine and plasma, urine-to-plasma ratios, and the urine depletion profile of firocoxib and to evaluate whether the pharmacokinetic behavior of firocoxib was governed by linear processes after multiple doses of firocoxib were administered IV and orally. Methods: 6 healthy female horses (5 Paint horses and 1 Quarter Horse) in experiment 1 and 12 healthy male and female horses in experiment 2. Methods: In experiment 1, 6 horses were orally administered firocoxib paste once daily for 12 consecutive days, and plasma ...
Leclere M, Lefebvre-Lavoie J, Beauchamp G, Lavoie JP.Orally administered prednisolone and dexamethasone are used commonly in the treatment of recurrent airway obstruction (RAO) in horses. However, the efficacy of prednisolone in improving pulmonary function during continuous antigen exposure has not been evaluated critically and there is little evidence supporting the efficacy of low-dose oral dexamethasone in the same conditions. Objective: Oral prednisolone and dexamethasone improve pulmonary function in RAO under conditions of continuous antigen exposure, and dexamethasone is more effective than prednisolone at commonly used dosages. Methods:...
Shilo Y, Britzi M, Eytan B, Lifschitz T, Soback S, Steinman A.Tramadol is a centrally acting analgesic drug that has been used clinically for the last two decades to treat moderate to moderately severe pain in humans. The present study investigated tramadol administration in horses by intravenous, intramuscular, oral as immediate-release and oral as sustained-release dosage-form routes. Seven horses were used in a four-way crossover study design in which racemic tramadol was administered at 2 mg/kg by each route of administration. Altogether, 23 blood samples were collected between 0 and 2880 min. The concentration of tramadol and its M1 metabolite were ...
Soma LR, Uboh CE, Liu Y, Li X, Robinson MA, Boston RC, Colahan PT.This study investigated and compared the pharmacokinetics of intra-articular (IA) administration of dexamethasone sodium phosphate (DSP) into three equine joints, femoropatellar (IAS), radiocarpal (IAC), and metacarpophalangeal (IAF), and the intramuscular (IM), oral (PO) and intravenous (IV) administrations. No significant differences in the pharmacokinetic estimates between the three joints were observed with the exception of maximum concentration (Cmax ) and time to maximum concentration (Tmax ). Median (range) Cmax for the IAC, IAF, and IAS were 16.9 (14.6-35.4), 23.4 (13.5-73.0), and 46.9...
Venner M, Credner N, Lämmer M, Giguère S.The objectives of the present study were to determine the relative efficacy of tulathromycin, azithromycin, or azithromycin with rifampin for the treatment of pulmonary abscesses on a farm with endemic infections caused by Rhodococcus equi. Foals with ultrasonographic evidence of pulmonary abscesses (abscess score 8.0-15 cm; n=120) were randomly allocated in four equal treatment groups: (1) tulathromycin intramuscularly; (2) azithromycin monotherapy, orally; (3) azithromycin with rifampin, orally; (4) saline intramuscularly as a placebo. Physical examination and thoracic ultrasonography were p...
Kaukinen H, Aspegrén J, Hyyppä S, Tamm L, Salonen JS.The objective of the study was to determine the absorption, bioavailability and sedative effect of detomidine administered to horses as an oromucosal gel compared to intravenous and intramuscular administration of detomidine injectable solution. The study was open and randomized, with three sequences crossover design. Nine healthy horses were given 40 μg/kg detomidine intravenously, intramuscularly or administered under the tongue with a 7-day wash-out period between treatments. Blood samples were collected before and after drug administration for the measurement of detomidine concentration...
Womble AY, Giguère S, Lee EA, Vickroy TW.To determine pharmacokinetics of clarithromycin and concentrations in body fluids and bronchoalveolar (BAL) cells of foals. Methods: 6 healthy 2-to 3-week-old foals. Methods: In a crossover design, clarithromycin (7.5 mg/kg) was administered to each foal via IV and intragastric (IG) routes. After the initial IG administration, 5 additional doses were administered IG at 12-hour intervals. Concentrations of clarithromycin and its 14-hydroxy metabolite were measured in serum by use of high-performance liquid chromatography. A microbiologic assay was used to measure clarithromycin activity in seru...
Gough S, Hallowell G, Rendle D.Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO). To compare rates of ESGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). Retrospective clinical study. The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared betwe...
Maxwell LK, Bentz BG, Bourne DW, Erkert RS.Recent outbreaks of equine herpes virus type-1 infections have stimulated renewed interest in the use of effective antiherpetic drugs in horses. The purpose of this study was to investigate the pharmacokinetics of valacyclovir (VCV), the prodrug of acyclovir (ACV), in horses. Six adult horses were used in a randomized cross-over design. Treatments consisted of 10 mg/kg ACV infused intravenously, 5 g (7.7-11.7 mg/kg) VCV delivered intragastrically (IG) and 15 g (22.7-34.1 mg/kg) VCV administered IG. Serum samples were obtained at predetermined times for acyclovir assay using high-performance li...
Zamos DT, Schumacher J, Loy JK.Nasopharyngeal conidiobolomycosis caused by Conidiobolus coronatus was diagnosed in a horse after endoscopic and histopathologic examinations of a biopsy specimen. The fungal lesions in the nasopharynx were substantially reduced in size after intralesional injection of amphotericin B through the biopsy channel of a videoendoscope in combination with i.v. administration of sodium iodide and oral administration of potassium iodide during a 2-month period. Endoscopy performed 15 months after initial examination revealed regression of the granulomatous masses in the nasopharynx and complete disapp...
Daurio CP, Holste JE, Andrews FM, Merritt AM, Blackford JT, Dolz F, Thompson DR.In a multicentre trial, 13 cannulated horses were treated orally once daily with a paste that delivered omeprazole at a dose of 4 and 5 mg/kg bwt in a 2-period crossover design to evaluate steady state gastric acid suppression. In each period, basal (unstimulated) and pentagastrin-stimulated gastric output were evaluated at 5-8 h after 5 doses, at 13-16 h after 10 doses, and at 21-24 h after 15 doses. Baseline data for gastric acid secretion were collected once for each horse in the month prior to initiation of omeprazole treatment. The inhibition of gastric acid secretion relative to baseline...
Garrison KL, Sahin S, Benet LZ.This study was conducted to determine the number of drugs exhibiting flip-flop pharmacokinetics following oral (p.o.) dosing from immediate-release dosage forms and if they exhibit a common characteristic that may be predicted based on BDDCS classification. The literature was searched for drugs displaying flip-flop kinetics (i.e., absorption half-life larger than elimination half-life) in mammals in PubMed, via internet search engines and reviewing drug pharmacokinetic data. Twenty two drugs were identified as displaying flip-flop kinetics in humans (13 drugs), rat (nine drugs), monkey (three ...
Du J, White N, Eddington ND.The purpose of this study was to determine if glucosamine (GL) hydrochloride (FCHG49) and low molecular weight (LMW) chondroitin sulfate (CS) (TRH122) are absorbed after oral administration to horses. The bioavailability of LMWCS was evaluated by quantifying the total disaccharides found in the plasma following chondroitinase ABC digestion. Methods: Two separate studies were conducted. In study 1, ten adult horses received the following four treatments in a randomized crossover fashion: (1) i.v. LMWCS (3 g of 8 kDa), (2) p.o. LMWCS (3 g of 8 kDa), (3) i.v. LMWCS (3 g of 16.9 kDa) and (4) p.o. ...
Dowling PM, Wilson RC, Tyler JW, Duran SH.The pharmacokinetics of ciprofloxacin was investigated in healthy, mature ponies. Ciprofloxacin was administered intravenously to six ponies at a dose of 5 mg per kg body weight. Seven days later, ciprofloxacin was administered orally to each pony at the same dose. Intravenous ciprofloxacin concentration vs. time data best fit a two-compartment open model with first-order elimination from the central compartment. Mean plasma half-life, based on the terminal phase, was 157.89 min (harmonic mean). Total body clearance of ciprofloxacin was 18.12 +/- 3.99 mL/min/kg. Volume of distribution at stead...
McKellar QA, Varma KJ.Florfenicol was administered to horses and ponies at a dose rate of 22 mg/kg bwt by i.v., i.m. and oral routes. Following i.v. administration it had an elimination half-life of 1.8 ± 0.9 h, a body clearance of 0.4 ± 0.11/h.kg and a volume of distribution at steady-state of 0.7 ± 0.2 1/kg. It was highly bioavailable following i.m. (81%) and oral (83%) administration. Less than 15% of the administered dose was excreted unchanged in the urine during the 30 h following administration. Animals treated with florfenicol had elevated bilirubin concentrations. Florfenicol was well tolerated by anima...
Grady JA, Davis EG, Kukanich B, Sherck AB.To assess pharmacokinetic and pharmacodynamic properties of dexamethasone administered PO as a solution or powder, compared with properties of dexamethasone solution administered IV, in apparently healthy horses. Methods: 6 adult horses. Methods: Serum cortisol concentration for each horse was determined before each treatment (baseline values). Dexamethasone (0.05 mg/kg) was administered PO (in solution or powdered form) or IV (solution) to horses from which feed had or had not been withheld (unfed and fed horses, respectively). Each horse received all 6 treatments in random order at 2-week in...
van Duijkeren E, Vulto AG, Sloet van Oldruitenborghoosterbaan MM, Mevius DJ, Kessels BG, Breukink HJ, van Miert AS.The biopharmaceutical properties of four fixed trimethoprim/sulfonamide combinations were investigated in the horse. Eight fasted horses were dosed at 1 week intervals in a sequentially designed study with one intravenous (i.v.) and three oral trimethoprim/sulfadiazine (TMP/SDZ) formulations (1, 2 and 3) administered at a dose of 5 mg/kg trimethoprim (TMP) and 25 mg/kg sulfadiazine (SDZ). Plasma concentrations of each compound were monitored for 48 h. Pharmacokinetic parameters (volume of distribution, bioavailability and total body clearance) for TMP and SDZ were calculated and compared. Afte...
McKellar QA, Bogan JA, von Fellenberg RL, Ludwig B, Cawley GD.Carprofen, a non-steroidal anti-inflammatory drug (NSAID) was administered to three Thoroughbred geldings and three Shetland ponies to determine its plasma disposition and tolerance. The main pharmacokinetic characteristics of carprofen in horses and ponies were a volume of distribution of 0.08 to 0.32 litres/kg (mean +/- se = 0.23 +/- 0.04) a systemic clearance of 26.4 to 78.5 ml/min (mean +/- se = 44.9 +/- 8.0) and a plasma elimination half-life of 14.5 to 31.4 h (mean +/- se = 21.9 +/- 2.3). There was no evidence of any accumulation of carprofen in plasma when the drug was given orally at a...
Schwarz BC, Sallmutter T, Nell B.A 6-year-old 680-kg (1,496-lb) German Warmblood gelding was evaluated because of bilateral blepharospasm and head shaking. Results: Moderate blepharospasm was evident bilaterally, and both eyes had hyperemic and edematous conjunctivas and lusterless corneas. For each eye, the Schirmer tear test value was only 7 mm/min. The horse's nasal mucosa was dry. Abnormal behaviors included mild repetitive vertical movement of the head, snorting, and flehmen response (classic signs of head shaking). Touching the horse's nostrils and face revealed paresthesia and dysesthesia with slight nasolabial muscle ...
