Intravenous administration in horses involves the delivery of substances directly into the bloodstream through a vein. This method is used to administer fluids, medications, and nutrients efficiently, ensuring rapid distribution throughout the body. It is commonly employed in veterinary practice for rehydration, anesthesia, and treatment of various medical conditions. The technique requires skill and knowledge to ensure proper vein selection and catheter placement, minimizing the risk of complications such as infection or thrombosis. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and potential complications associated with intravenous administration in equine medicine.
Levionnois OL, Menge M, Thormann W, Mevissen M, Spadavecchia C.The purpose of this study was to evaluate the anti-nociceptive activity of ketamine and isoflurane in horses using a limb withdrawal reflex (WR) model. Single and repeated stimulations were applied to the digital nerve of the left forelimb in ponies anaesthetised with isoflurane before, during and after intravenous administration of racemic ketamine. Surface electromyographic activity was recorded from the deltoid muscle. Higher stimulation intensity was required to evoke a reflex during ketamine administration. Furthermore, the amplitudes of response to stimulations were significantly and dos...
Brosnan RJ, Steffey EP.We hypothesized that propofol can produce rapidly-reversible, dose-dependent standing sedation in horses. Methods: Prospective randomized, blinded, experimental trial. Methods: Twelve healthy horses aged 12 +/- 6 years (mean +/- SD), weighing 565 +/- 20 kg, and with an equal distribution of mares and geldings. Methods: Propofol was administered as an intravenous bolus at one of three randomized doses (0.20, 0.35 and 0.50 mg kg(-1)). Cardiovascular and behavioral measurements were made by a single investigator, who was blinded to treatment dose, at 3 minute intervals until subjective behavior s...
Steffey EP, Mama KR, Brosnan RJ, Imai A, Maxwell LK, Cole CA, Stanley SD.To compare characteristics of horses recovering from 4 hours of desflurane anesthesia with and without immediate postanesthetic IV administration of propofol and xylazine. Animals-8 healthy horses (mean +/- SEM age, 6.6 +/- 1.0 years; mean body weight, 551 +/- 50 kg). Methods: Horses were anesthetized twice. Both times, anesthesia was induced with a combination of xylazine hydrochloride, diazepam, and ketamine hydrochloride and then maintained for 4 hours with desflurane in oxygen. Choice of postanesthetic treatment was randomly assigned via a crossover design such that each horse received an ...
Poulin Braim AE, MacDonald MH, Bruss ML, Grattendick KJ, Giri SN, Margolin SB.To characterize effects of IV administration of pirfenidone on clinical, biochemical, and hematologic variables and circulating tumor necrosis factor (TNF)-alpha concentrations in horses after infusion of a low dose of endotoxin. Methods: 18 healthy adult horses. Methods: Horses were randomly assigned to 3 groups (n = 6 horses/group) and administered an IV infusion of 30 ng of endotoxin/kg or saline (0.9% NaCl) solution during a 30-minute period. Lipopolysaccharide-pirfenidone horses received endotoxin followed by pirfenidone (loading dose of 11.6 mg/kg and then constant rate infusion [CRI] at...
Hubbell JA, Sams RA, Schmall LM, Robertson JT, Hinchcliff KW, Muir WW.Increased doses of detomidine are required to produce sedation in horses after maximal exercise compared to calm or resting horses. Objective: To determine if the pharmacokinetics of detomidine in Thoroughbred horses are different when the drug is given during recuperation from a brief period of maximal exercise compared to administration at rest. Methods: Six Thoroughbred horses were preconditioned by exercising them on a treadmill. Each horse ran a simulated race at a treadmill speed that caused it to exercise at 120% of its maximal oxygen consumption. One minute after the end of exercise, h...
Meyer S, Giguère S, Rodriguez R, Zielinski RJ, Grover GS, Brown SA.The objectives of this study were to determine pharmacokinetics of intravenous (i.v.) ceftiofur in foals, to compare ultra-high performance liquid chromatography tandem mass spectometry (UPLC-MS/MS) and microbiologic assay for the measurement of ceftiofur concentrations, and to determine the minimum inhibitory concentration (MIC) of ceftiofur against common equine bacterial pathogens. In a cross-over design, ceftiofur sodium was administered i.v. to six foals (1-2 days-of-age and 4-5 weeks-of-age) at dosages of 5 and 10 mg/kg. Subsequently, five doses of ceftiofur were administered i.v. to six...
Doherty TJ.Surgical manipulation of the intestines activates intestinal macrophages that release cytokines and nitric oxide, which results in inhibition of intestinal motility. Subsequent infiltration of circulating leukocytes into the intestinal wall contributes to cytokine and nitric oxide release and exacerbates ileus. Other factors contributing to ileus are endotoxemia; edema of the intestine wall subsequent to excessive fluid therapy; hypocalcemia; and long abdominal incisions. Because treatment of ileus with prokinetic drugs has not proven to be very effective, efforts should be directed at reducin...
Grimsrud KN, Mama KR, Thomasy SM, Stanley SD.Detomidine is commonly used i.v. for sedation and analgesia in horses, but the pharmacokinetics and metabolism of this drug have not been well described. Objective: To describe the pharmacokinetics of detomidine and its metabolites, 3-hydroxy-detomidine (OH-detomidine) and detomidine 3-carboxylic acid (COOH-detomidine), after i.v. and i.m. administration of a single dose to horses. Methods: Eight horses were used in a balanced crossover design study. In Phase 1, 4 horses received a single dose of i.v. detomidine, administered 30 microg/kg bwt and 4 a single dose i.m. 30 microg/kg bwt. In Phase...
Rohrbach H, Korpivaara T, Schatzmann U, Spadavecchia C.To evaluate and compare the antinociceptive effects of the three alpha-2 agonists, detomidine, romifidine and xylazine at doses considered equipotent for sedation, using the nociceptive withdrawal reflex (NWR) and temporal summation model in standing horses. Methods: Prospective, blinded, randomized cross-over study. Methods: Ten healthy adult horses weighing 527-645 kg and aged 11-21 years old. Methods: Electrical stimulation was applied to the digital nerves to evoke NWR and temporal summation in the left thoracic limb and pelvic limb of each horse. Electromyographic reflex activity was reco...
Ginther OJ, Siddiqui MA, Beg MA.The hypotheses were tested that prostaglandin F2alpha (PGF) travels from the uterus to the ovaries via a systemic route in mares, as opposed to a local route in ruminants, and that one pulse of PGF produces only partial luteolysis. Intravenous (i.v.) and intrauterine (i.u.) infusions of PGF were performed 8 days after ovulation at a constant rate for 2 h. Plasma concentrations of PGF were assessed by assay of 13,14-dihydro-15-keto-PGF2alpha (PGFM). Total doses administered were as follows: 0, 0.05, 0.1, 0.5 and 1.0 mg, i.v., PGF and 0 and 0.5 mg, i.u., PGF (n=4 mares per group). In addition, P...
Nyman G, Marntell S, Edner A, Funkquist P, Morgan K, Hedenstierna G.Sedation with alpha2-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET), during sedation with the alpha2-agonist detomidine alone and in combination with the opioid butorphanol. Methods: Seven Standardbred trotter horses aged 3-7 years and weighing 380-520 kg, were studied. The protocol consisted of three consecutive measurements; in the unsedated horse, after intravenous administration of detomidine (0.02 mg/kg) and after sub...
Hustace JL, Firshman AM, Mata JE.To determine pharmacokinetics and oral bioavailability of metformin in healthy horses. Methods: 4 adult horses. Methods: 6 g of metformin was administered 3 times IV and PO (fed and unfed) to each horse, by use of a crossover design, with a 1-week washout period between treatments. Plasma metformin concentration was determined via high-pressure liquid chromatography. Results: Mean +/- SD distribution half-life of metformin following IV administration was 24.9 +/- 0.4 minutes with a volume of distribution of 0.3 +/- 0.1 L/kg. Mean area under the curve was 20.9 +/- 2.0 h.microg/mL for IV adminis...
Wong DM, Vo DT, Alcott CJ, Stewart AJ, Peterson AD, Sponseller BA, Hsu WH.The purpose of this study was to investigate total baseline plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations, and ACTH-stimulated cortisol concentrations in foals from birth to 12 wk of age. Plasma (baseline) cortisol and ACTH concentrations were measured in 13 healthy foals at birth and at 1, 2, 3, 4, 5, 7, 10, 14, 21, 28, 42, 56, and 84 d of age. Each foal received cosyntropin (0.1 microg/kg) intravenously. Plasma cortisol concentrations were measured before (baseline), and 30, and 60 min after cosyntropin administration at birth and at 3, 5, 7, 10, 14, 21, 28, 42, 56, a...
Reijerkerk EP, Visser EK, van Reenen CG, van der Kolk JH.To compare the effects of IV administration of various doses of ovine corticotrophin-releasing hormone (oCRH) on plasma and saliva cortisol concentrations in healthy horses and determine whether an oCRH challenge test protocol is valid for use in adult horses. Methods: 24 healthy Warmblood horses. PROCEDURES-Each horse received oCRH in saline (0.9% NaCl) via IV administration at a dose of 0 (control treatment), 0.01, 0.1, or 1.0 Mg/kg (6 horses/group). Jugular blood and saliva samples were collected simultaneously 15 minutes before and immediately prior to injection (baseline); data from these...
Portier KG, Jaillardon L, Leece EA, Walsh CM.To evaluate the effects of local anaesthesia with lidocaine for castration of horses under intravenous anaesthesia. Methods: Prospective, randomized, blinded clinical trial. Methods: Fifteen equidae, scheduled to undergo castration under total intravenous anaesthesia, were randomly distributed in two groups. One group received lidocaine injections (group L: two ponies, four horses, two donkeys) and the other received saline (group S: two ponies, three horses, two donkeys). Methods: Behaviour, heart rate (HR) and respiratory rate (f(R)) were evaluated prior to anaesthesia. Body mass was measure...
De Clercq D, van Loon G, Tavernier R, Verbesselt R, Deprez P.To investigate effects of IV administration of propafenone for naturally occurring and experimentally induced chronic atrial fibrillation in horses. Methods: 2 horses with naturally occurring atrial fibrillation and 4 horses with pacing-induced atrial fibrillation. Methods: Horses received a bolus of propafenone (2 mg/kg, IV over 15 minutes). If atrial fibrillation persisted after 20 minutes, a continuous infusion of propafenone (7 microg/kg/min) was given for 120 minutes. Before, during, and after treatment, plasma propafenone concentrations, hematologic and serum biochemical values, and elec...
Geraghty TE, Love S, Taylor DJ, Heller J, Mellor DJ, Hughes KJ.A total of 102 horses that had a catheter introduced intravenously to facilitate treatment had the catheterised jugular vein and contralateral vein examined by ultrasound every 48 hours. Subclinical complications were defined by thrombus formation or thickening of the venous wall, and the data were analysed to establish risk factors for the development of these complications. The horses with a rectal temperature above 38.5 degrees C when the catheter was introduced were four times more likely to develop complications, than the horses with a lower temperature. The administration of a NSAID whil...
Schramme AR, Pinto CR, Davis J, Whisnant CS, Whitacre MD.Current therapy protocols to treat persistent post mating endometritis and retained fetal membranes in mares typically include the administration of ecbolic drugs. Evaluation of the pharmacokinetics and tolerability of carbetocin, a long-acting oxytocin analogue, after i.v. administration is required. Objective: To determine the pharmacokinetic parameters (principally half-life) of carbetocin in horses. Methods: Five mature mares and one gelding received 0.175 mg carbetocin i.v. All animals were monitored periodically throughout the study for elevation in rectal temperature, heart rate, respir...
Sellon DC, Papich MG, Palmer L, Remund B.A two-way cross-over study of the pharmacokinetics of butorphanol after intravenous and intramuscular administration at 0.08 mg/kg in six adult horses was performed. Heparinized venous blood samples were obtained prior to drug administration and at 10, 20, 30, 45, 60, 120, 180, 240, and 360 min after IV injection. Samples were obtained at the same time points and at 6 h and 12 h after IM injection. Physical examination parameters were recorded at each time point. Plasma butorphanol concentrations were determined by high performance liquid chromatography. No significant differences in any physi...
Dirikolu L, Lehner AF, Harkins JD, Woods WE, Karpiesiuk W, Gates RS, Fisher M, Tobin T.Pyrilamine is an antihistamine used in human and veterinary medicine. As antihistamines produce central nervous system effects in horses, pyrilamine has the potential to affect the performance of racehorses. In the present study, O-desmethylpyrilamine (O-DMP) was observed to be the predominant equine urinary metabolite of pyrilamine. After intravenous (i.v.) administration of pyrilamine (300 mg/horse), serum pyrilamine concentrations declined from about 280 ng/mL at 5 min postdose to about 2.5 ng/mL at 8 h postdose. After oral administration of pyrilamine (300 mg/horse), serum concentrations p...
Geraghty TE, Love S, Taylor DJ, Heller J, Mellor DJ, Hughes KJ.The sites of insertion of catheters into the jugular veins of six horses were investigated to determine common isolates and to assess the effectiveness of two disinfection protocols with the hair coat left long, clipped or shaved. Skin commensals (Staphylococcus, Streptococcus and Micrococcus species) and environmental contaminants (Bacillus, Enterobacteriaceae, Aspergillus and Mucor species) were the microorganisms most frequently isolated. Chlorhexidine gluconate and povidone-iodine-based skin disinfection protocols resulted in significant reductions in the number of bacterial isolates from ...
Molleda JM, Cervantes I, Galán A, Tardón R, Gallardo JM, Martín-Suárez EM.To describe the protocol and appearance of fluorescein angiography (FA) in normal horses. Methods: A total of 25 healthy horses aged between 5 and 15 years. Methods: The horses were sedated with 15 microg/kg detomidine and 50 microg/kg butorphanol and dilated with topical tropicamide 1%. All angiograms were recorded after intravenous bolus injection of 10 mg/kg of fluorescein sodium solution. Results: Two successive angiographic phases could be discerned: the choriopapillary phase, starting at 46.95 +/- 9.48 s, and the retinal vascular phase, starting at 47.79 +/- 10.38 s. The retinal vascular...
Ferraz GC, Teixeira-Neto AR, Mataqueiro MI, Lacerda-Neto JC, Queiroz-Neto A.To investigate the effect of acute administration of caffeine on the athletic performance of Arabian horses. Methods: 12 healthy adult Arabian horses that were trained for exercise on a treadmill. Methods: By use of a crossover study design, horses received each of the following treatments: IV administration of caffeine (5 mg/kg) and IV administration of approximately the same volume of saline (0.9% NaCl) solution. Order of treatment was randomized, and there was a 10-day interval between treatments. Thirty minutes after treatments, horses underwent an incremental exercise test (IET) on a trea...
Goudah A, Abo El-Sooud K, Shim JH, Shin HC, Abd El-Aty AM.The target of the present study was to investigate the plasma disposition kinetics of levofloxacin in stallions (n = 6) following a single intravenous (i.v.) bolus or intramuscular (i.m.) injection at a dose rate of 4 mg/kg bwt, using a two-phase crossover design with 15 days as an interval period. Plasma samples were collected at appropriate times during a 48-h administration interval, and were analyzed using a microbiological assay method. The plasma levofloxacin disposition was best fitted to a two-compartment open model after i.v. dosing. The half-lives of distribution and elimination were...
Camargo FC, Robinson NE, Dirikolu L, Berney C, Eberhart S, Derksen FJ, Lehner AF, May J, Hughes C, Tobin T.Trimetoquinol (TMQ) is a very potent and fast acting bronchodilator in horses with heaves. This study assessed the plasma and urinary concentrations of TMQ in horses with heaves following administration via the intravenous (IV, 0.2 microg/kg) and intra-tracheal (IT, 2 microg/kg) routes. TMQ was administered to six horses affected with heaves (RAO - Recurrent Airway Obstruction, used interchangeably) by the above routes and plasma and urine samples collected and stored at -20 degrees C until analyzed. Solid Phase Extraction (SPE) of TMQ was followed by highly sensitive ESI(+)-LC-MS-MS (ElectroS...
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 ...
Arguedas MG, Hines MT, Papich MG, Farnsworth KD, Sellon DC.Despite frequent clinical use, information about the pharmacokinetics (PK), clinical effects, and safety of butorphanol in foals is not available. Objective: The purpose of this study was to determine the PK of butorphanol in neonatal foals after IV and IM administration; to determine whether administration of butorphanol results in physiologic or behavioral changes in neonatal foals; and to describe adverse effects associated with its use in neonatal foals. Methods: Six healthy mixed breed pony foals between 3 and 12 days of age were used. Methods: In a 3-way crossover design, foals received ...
Haffner JC, Eiler H, Hoffman RM, Fecteau KA, Oliver JW.Sustained dexamethasone administration to horses results in insulin resistance, which may predispose them to laminitis. A single dose of dexamethasone is commonly used as a diagnostic aid, yet the effect of a single dose of dexamethasone on glucose homeostasis in horses is not well defined. The objective of this study was to characterize the change in glucose dynamics over time in response to a single dose of dexamethasone. A combined glucose-insulin tolerance test (CGIT) was performed on 6 adult geldings before and at 2, 24, and 72 h postdexamethasone (40 microg/kg of BW, i.v.); a minimum of ...
Davidson GS.Anesthetization of large animals, such as the horse, is a challenge for veterinarians and compounding pharmacists. This article discusses the technique of intravenous anesthesia by using a combination of xylazine and ketamine in the horse for short-term unconsciousness; a combination of xylazine, diazepam, and ketamine, for improved sedation and muscle relaxation; and a combination of xylazine, ketamine, and guaifenesin, referred to as Triple Drip, for the maximum 1-hour duration of unconsciousness. Compounding pharmacists that have the facilities and training required to prepare sterile compo...
Bollwein H, Schulze JJ, Miyamoto A, Sieme H.The goal of this study was to investigate for the first time a possible association between plasma concentrations of testosterone and total estrogen and testicular blood flow in the stallion. Correlations between these variables were calculated before and after administration of human chorionic gonadotropin (hCG). Eight mature warmblood stallions received 5,000 IU hCG intravenously, and four stallions received solvent only. Testicular blood flow in the left and right testicular arteries was assessed using colour Doppler sonography by measuring blood flow volume (BFV) and pulsatility index (PI)...
Umar MA, Yamashita K, Kushiro T, Muir WW.Objective-To compare the anesthetic and cardiorespiratory effects of total IV anesthesia with propofol (P-TIVA) or a ketamine-medetomidine-propofol combination (KMP-TIVA) in horses. Design-Randomized experimental trial. Animals-12 horses. Procedure-Horses received medetomidine (0.005 mg/kg [0.002 mg/lb], IV). Anesthesia was induced with midazolam (0.04 mg/kg [0.018 mg/lb], IV) and ketamine (2.5 mg/kg [1.14 mg/lb], IV). All horses received a loading dose of propofol (0.5 mg/kg [0.23 mg/lb], IV), and 6 horses underwent P-TIVA (propofol infusion). Six horses underwent KMP-TIVA (ketamine [1 mg/kg/...
Bringewatt T, Hopster K, Kästner SB, Rohn K, Ohnesorge B.The influence of a modified open lung concept (mOLC) on pulmonary and cardiovascular function during total intravenous anaesthesia (TIVA) in horses was evaluated. Forty-two warmblood horses (American Society of Anesthesiologists class 1 to 2), scheduled for elective surgery (mean [sd] weight 526 [65] kg, age 6.4 [5.4] years) were randomly divided into three groups: ventilation with mOLC, intermittent positive-pressure ventilation (IPPV), and spontaneous breathing. Premedication (0.8 mg/kg xylazine), induction (2.2 mg/kg ketamine and 0.05 mg/kg diazepam) and maintenance of anaesthesia with TIVA...
Haddad NS, Pedersoli WM, Ravis WR, Fazeli MH, Carson RL.Healthy mature pony mares (n = 6) were given a single dose of gentamicin (5 mg/kg of body weight) IV or IM 8 days apart. Venous blood samples were collected at 0, 5, 10, 20, 30, and 45 minutes and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 18, 24, 30, 36, 40, and 48 hours after IV injection of gentamicin, and at 10, 20, 30, and 45 minutes and at 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 18, 24, and 30 hours after IM injection of gentamicin. Gentamicin serum concentration was determined by a liquid-phase radioimmunoassay. The combined data of IV and IM treatments were analyzed by a nonlinear least-square...
Trachsel D, Tschudi P, Portier CJ, Kuhn M, Thormann W, Scholtysik G, Mevissen M.Atrial fibrillation is a well-known heart disease in horses. The common therapy consists of administration of quinidine. More potent antiarrhythmic drugs have become available for human therapy and the use of these as alternatives to quinidine for equine antiarrhythmic therapy is a matter of interest. Amiodarone (AMD) is used in human medicine for treatment of many arrhythmias, including atrial fibrillation. Its disposition in horses has not yet been investigated. The purpose of this study was to measure the effect of single intravenous doses of amiodarone (5 and 7 mg/kg) on the surface electr...
Guillaume D, Rio N, Toutain PL.The aims of the present study were to determine basic kinetic parameters and the nycthemeral production rate of melatonin in the horse. Seven pony mares were used for the kinetic studies. Five other pony mares were used under long and short days for the production rate studies. Melatonin was administered by intravenous, oral, and intragastric routes at different dose levels. The plasma melatonin clearance was 1.02 +/- 0.31 l.kg-1.h-1, and the volume of distribution was 0.89 +/- 0.53 l/kg for the 0.4 microgram/kg melatonin dose. The systemic availability after oral and intragastric administrati...
Young LE, Blissitt KJ, Clutton RE, Molony V.To evaluate temporal hemodynamic effects of dobutamine in horses anesthetized with halothane. Methods: 8 adult Thoroughbreds. Methods: Anesthesia was induced by i.v. administration of romifidine and ketamine and maintained using halothane in oxygen. After 60 minutes, dobutamine was administered i.v. for 60 minutes at 4 micrograms/kg of body weight/min. Measurements of left ventricular function were obtained by transesophageal echocardiography and cardiac catheterization. Results: Mean, systolic, diastolic, aortic, pulmonary arterial, and left and right ventricular end-diastolic and systolic pr...
Jöchle W, Irvine CH, Alexander SL, Newby TJ.Nine mares received cannulae to collect blood from the pituitary venous outflow in the intercavernous sinus (ICS) and the jugular vein; in 4 mares, only jugular cannulae were used. Those 4 mares and 3 of the mares with cannulae in both positions received 7.5 mg luprostiol i.m. and 1 mare with both cannulae was treated with 3.75 mg uprostiol i.v. Blood samples were kept before and after treatment at 2-, 5- or 10-min intervals and concentrations of LH, FSH and GnRH were determined by RIA. Treatments resulted in an immediate sharp rise of LH and FSH in ICS and jugular blood samples within 2-10 mi...
Farag AMM, Ibrahim HMM.The current study was undertaken to investigate the effect of intravenous administration of ondansetron on the small and large intestinal motility in donkeys (Equus asinus) using non-invasive transabdominal ultrasonography. The current prospective, randomized, placebo-controlled, crossover study was conducted on thirty healthy donkeys (15 males and 15 females). The selected donkeys underwent two trials; the first was performed by intravenous administration of saline solution as a placebo, while the second was carried out by intravenous administration of ondansetron hydrochloride. The contracti...
Jöchle W.In this uncontrolled clinical study 12 investigators cooperated to evaluate the analgesic and sedative effect of detomidine (DORMOSEDAN; Farmos Group Ltd; Finland) in 234 horses with abdominal pain caused by colic. The study was designed to use each animal as its own control and to evaluate its response to the drug over a 60 min period. Detomidine was given intravenously (i.v.) once in 169 cases (167 horses, 1 mule, 1 donkey) at a dose of 20 micrograms/kg bodyweight (bwt), and to 65 horses at 40 micrograms/kg bwt. The higher dose was used predominantly in horses with severe pain which were mor...
Geraghty TE, Love S, Taylor DJ, Heller J, Mellor DJ, Hughes KJ.The sites of insertion of catheters into the jugular veins of six horses were investigated to determine common isolates and to assess the effectiveness of two disinfection protocols with the hair coat left long, clipped or shaved. Skin commensals (Staphylococcus, Streptococcus and Micrococcus species) and environmental contaminants (Bacillus, Enterobacteriaceae, Aspergillus and Mucor species) were the microorganisms most frequently isolated. Chlorhexidine gluconate and povidone-iodine-based skin disinfection protocols resulted in significant reductions in the number of bacterial isolates from ...
Pratt S, Cunneen A, Perkins N, Farry T, Kidd L, McEwen M, Rainger J, Truchetti G, Goodwin W.There is no information directly comparing midazolam with guaifenesin when used in combination with an alpha-2 agonist and ketamine to maintain anaesthesia via i.v. infusion in horses. Objective: To compare ketamine-medetomidine-guaifenesin with ketamine-medetomidine-midazolam for total intravenous anaesthesia (TIVA) in young horses anaesthetised for computerised tomography. Methods: Prospective, randomised, blinded, crossover trial. Methods: Fourteen weanlings received medetomidine 7 μg/kg bwt i.v. and anaesthesia was induced with ketamine 2.2 mg/kg bwt i.v. On two separate occasions hors...
Prescott JF, Hoover DJ, Dohoo IR.The pharmacokinetic parameters of erythromycin in foals were determined following intravenous administration of 5.0 mg/kg to animals aged 1, 3, 5 and 7 weeks. The distribution of the drug was described by a two-compartment open model, and no significant differences were observed between coefficients on which the parameters were based. Pharmacokinetic values were also determined for four mares given 5.0 mg/kg intravenously and for six 10-12-week-old foals given 20.0 mg/kg intravenously. The half-life of erythromycin for all groups of animals (foals less than 7 weeks, mares, foals 10-12 weeks) w...
Doherty TJ, Andrews FM, Abraha TW, Osborne D, Frazier DL.The effect of metoclopramide on gastric emptying of a liquid marker in horses was evaluated by measuring serum concentrations of acetaminophen. Gastric emptying was determined in normal, fasted horses (n = 7), horses given endotoxin intravenously (n = 7), and horses given intravenous metoclopramide plus endotoxin (n = 6). The mean time to reach maximum serum acetaminophen concentration (Tmax), the maximum serum concentration (Cmax), and the area under the serum acetaminophen concentration vs time curve (AUC) were compared among treatment groups. Endotoxin caused a profound delay in gastric emp...
Spehar AM, Hill MR, Mayhew IG, Hendeles L.Pharmacokinetic characteristics of the anticonvulsant phenobarbital were studied in seven pony and two Thoroughbred foals aged between four and 10 days. A single, 20 mg/kg bodyweight (bwt) dose of phenobarbital was given intravenously over 25 mins and the serum concentrations of the drug were measured using an EMIT AED assay (coefficient of variation 1.37 per cent at 30 micrograms/ml, n = 7). Phenobarbital elimination was found to follow first order kinetics. The mean (+/- sd) peak phenobarbital serum concentration was 18.6 +/- 2.1 micrograms/ml at 1 h after initiation of infusion with a mean ...
Romagnoli N, Al-Qudah KM, Armorini S, Lambertini C, Zaghini A, Spadari A, Roncada P.The aims of this study were to assess the plasma concentrations of romifidine in horses after intravenous injection, to evaluate the red blood cell (RBC) partitioning of the anaesthetic drug, and to improve knowledge regarding its sedative effect in horses describing the pharmacokinetic model. Eight adult Standardbred horses received a single bolus of romifidine at a dosage of 100 g/kg. Blood samples (5 mL) were collected immediately before romifidine administration (), and at 2, 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 90, 105, 120, 150 and 180 min after injection. A sedation score was recor...
Brown MP, Kelly RH, Stover SM, Gronwall R.Six healthy adult mares were given a single IV injection of trimethoprim (TMP)-sulfadiazine (SDZ) at a dosage rate of 2.5 mg of TMP/kg of body weight and 12.5 mg of SDZ/kg. Serum, synovial, peritoneal, and urine TMP-SDZ concentrations were measured serially over a 48-hour period. The highest measured mean concentrations of TMP and SDZ were found in the first (0.5 hour) sample of serum, synovial fluid, and peritoneal fluid. The mean peak concentrations of TMP and SDZ averaged 4.37 micrograms/ml and 21.81 micrograms/ml for serum, 2.95 micrograms/ml and 15.31 micrograms/ml for synovial fluid, and...
Blythe LL, Craig AM, Christensen JM, Appell LH, Slizeski ML.Dimethyl sulfoxide (DMSO) was administered IV to 6 Thoroughbred horses at 2 dosages: 1.0 g/kg and 0.1 g/kg. The pharmacokinetics seemed linear, with biological half-lives of 8.6 +/- 0.3 hours and 9.8 +/- 2.2 hours for the 1.0 g/kg and 0.1 g/kg dosages, respectively. This was further substantiated by mean residence times of 9.8 +/- 0.44 hours and 13.8 +/- 4.25 hours, areas under the curve of 12.55 +/- 1.42 mg/ml/hr and 1.63 +/- 0.49 mg/ml/hr, and the clearances of 0.081 +/- 0.009 L/kg/hr and 0.066 +/- 0.022 L/kg/hr for the large and small dosages, respectively. At 12 hours after 1.0 g/kg was ad...
Donecker JM, Sams RA, Ashcraft SM.The pharmacokinetics and bioavailability of probenecid given IV and orally at the dosage level of 10 mg/kg of body weight to mares were investigated. Probenecid given IV was characterized by a rapid disposition phase with a mean half-life of 14.0 minutes and a subsequent slower elimination phase with a mean half-life of 87.8 minutes in 5 of 6 mares. In the remaining mare, a rapid disposition phase was not observed, and the half-life of the elimination phase was slower (172 minutes). The mean residence time of probenecid averaged 116 minutes for all 6 mares and 89.2 minutes for the 5 mares with...
Wilcke JR, Crisman MV, Scarratt WK, Sams RA.To determine pharmacokinetic variables that describe disposition of ketoprofen after its i.v. administration to foals < 24 hours old. Methods: 6 healthy foals (1 male and 5 females); mean age, 12.5 (range, 8.5 to 17) hours at time of dose administration. Methods: Ketoprofen was administered i.v. to foals at a dosage of 2.2 mg/kg of body weight. Ketoprofen concentration in plasma samples was analyzed, using high-performance liquid chromatography. Concentration versus time profiles were analyzed according to standard pharmacokinetic techniques. Blood samples were obtained from foals by jugula...
Ruoff WW, Sams RA.The pharmacokinetics and bioavailability of cephalothin given to 6 horse mares at a dosage level of 11 mg/kg of body weight IV or IM were investigated. The disposition of cephalothin given IV was characterized by a rapid disposition phase with a mean half-life of 2.89 minutes and a subsequent slower elimination phase with a mean half-life of only 14.7 minutes. The mean residence time of cephalothin was 10.6 +/- 2.11 minutes. The total plasma clearance of cephalothin averaged 13.6 ml/min/kg and was caused by metabolism and renal elimination. Renal clearance of cephalothin averaged 1.32 ml/min/k...
Hashem A, Keller H.The pharmacokinetics and pharmacological efficacy of orally (p.o.) administered acepromazine were studied and compared with the intravenous (i.v.) route of administration in a cross-over study using six horses. The oral kinetics of acepromazine can be described by a two-compartment open model with first-order absorption. The drug was rapidly absorbed after p.o. administration with a half-life of 0.84 h, tmax of 0.4 h and Cmax of 59 ng/ml. The elimination was slower after p.o. administration (half-life 6.04 h) than after i.v. injection (half-life 2.6 h). The bioavailability of the orally admini...
Galecio JS, Escudero E, Badillo E, Marín P.Tildipirosin is a novel semisynthetic macrolide antibiotic exclusively used in veterinary practice to treat respiratory infections. There are no pharmacokinetic or safety information available regarding the use of tildipirosin after intramuscular administration in horses. Thus, the objective of this work was to determine the disposition kinetics of tildipirosin after intravenous (IV) and intramuscular (IM) administration in horses and its potential muscle damage and cardiotoxicity. Six mature, Spanish-breed horses were used in a crossover study with a washout period of 30 days. Tildipirosin (...
Levionnois OL, Menge M, Thormann W, Mevissen M, Spadavecchia C.The purpose of this study was to evaluate the anti-nociceptive activity of ketamine and isoflurane in horses using a limb withdrawal reflex (WR) model. Single and repeated stimulations were applied to the digital nerve of the left forelimb in ponies anaesthetised with isoflurane before, during and after intravenous administration of racemic ketamine. Surface electromyographic activity was recorded from the deltoid muscle. Higher stimulation intensity was required to evoke a reflex during ketamine administration. Furthermore, the amplitudes of response to stimulations were significantly and dos...
Bryant CE, Clarke KW, Thompson J.Medetomidine was administered intravenously to six sheep at 5, 10 and 20 micrograms kg-1 and to one horse and four ponies at 5 and 10 micrograms kg-1. In both species medetomidine resulted in significant decreases in heart rate and cardiac output and, initially, in an increase in arterial blood pressure. In the ponies this increase in blood pressure was followed by a significant and prolonged decrease, but in the sheep the secondary decrease in blood pressure was not statistically significant. In the sheep, the three doses of medetomidine resulted in profound and significant decreases in arter...
Sams RA, Gerken DF, Ashcraft SM.The objectives of the study were to compare various methods to determine flunixin in test samples collected periodically from horses after intramuscular (IM) and intravenous (IV) dosing at the maximum recommended dosage and to document detection times for this drug in test samples. Flunixin, a nonsteroidal anti-inflammatory drug approved for use in horses, was administered to eight mares in five consecutive daily doses of 1.1 mg per kilogram of body weight by the IM or IV route. Flunixin was detected in urine samples collected at various times after drug administration by flunixin enzyme-linke...
Reed R, Barletta M, Mitchell K, Hanafi A, Bullington A, Knych H, Quandt J, Ryan C, Giguère S.Describe the pharmacokinetics and pharmacodynamics of intravenous hydromorphone in healthy horses. Methods: Masked, randomized, cross-over, Latin square design. Methods: A group of eight healthy adult horses METHODS: Horses were administered each of four treatments with an 8 day washout. Treatments groups included intravenous hydromorphone 0.02 mg kg (LD), 0.04 mg kg (MD), 0.08 mg kg (HD) and saline (P). Blood samples for hydromorphone analysis were obtained for 24 hours after treatment. Plasma hydromorphone was quantified and pharmacokinetic parameters were determined using non-compartmental ...
Morresey PR, White GW, Poole HM, Hu T, Yin M, Sundman EA.OBJECTIVE To evaluate the effectiveness and safety of dipyrone to control pyrexia in horses with naturally occurring disease under field conditions. ANIMALS 138 horses with pyrexia and various infections evaluated at 14 veterinary sites in 12 states. PROCEDURES In the first (effectiveness) phase of this 2-phase study, horses were randomly assigned 3:1 to receive 1 dose of dipyrone (30 mg/kg [13.6 mg/lb], IV) or an equivalent amount of placebo. Effectiveness was defined as a decrease in rectal temperature ≥ 1.1°C (2°F), compared with the pretreatment value, or a rectal temperature of ≤ 38...
Davis JL, Salmon JH, Papich MG.The purpose of this study was to determine the pharmacokinetics and tissue fluid distribution of cephalexin in the adult horse following oral and i.v. administration. Cephalexin hydrate (10 mg/kg) was administered to horses i.v. and plasma samples were collected. Following a washout period, cephalexin (30 mg/kg) was administered intragastrically. Plasma, interstitial fluid (ISF) aqueous humor, and urine samples were collected. All samples were analyzed by high-pressure liquid chromatography (HPLC). Following i.v. administration, cephalexin had a plasma half-life (t(1/2)) of 2.02 h and volume o...
Burrows GE.Phenylbutazone (PBZ), a classic anti-inflammatory and prostaglandin-synthesis inhibitor drug, was used to determine the role of prostaglandins and other mediators on the development and perpetuation of the response to intraperitoneal Escherichia coli endotoxin administration. The PBZ (15 mg/kg of body weight) was administered IV 30 minutes after endotoxin administration and was repeated later at 6 and 12 hours at a dose of 10 mg/kg. A variety of evaluation measurements (hematologic, blood glucose, pyruvate, lactate and fibrinogen, serum beta-glucuronidase, prothrombin time, blood gases, hepati...
Hunt RJ, Brandon CI, McCann ME.Palmar digital arterial blood flow was measured in 6 conscious, standing horses, using surgically placed perivascular ultrasonic flow probes. The effects of 2 dosages of xylazine (0.55 and 1.1 mg/kg of body weight) and of 3 dosages of acetylpromazine (0.01, 0.02, and 0.04 mg/kg), as well as the effect of vertical load, on digital blood flow were evaluated. Intravenous administration of xylazine induced a significant (P < 0.05), transient decrease in digital blood flow. Intravenous administration of acetylpromazine induced a significant (P < 0.05), prolonged increase in digital blood flow...
