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.
Steinman A, Isoherranen N, Ashoach O, Soback S.Gentamicin pharmacokinetics has not been studied in horses. Pharmacokinetics of gentamicin C1, C1a and C2 components following i.v. administration of total gentamicin at 6.6 mg/kg bwt to 6 healthy mature horses was determined. Significant differences in clearance, half-life (t 1/2), and mean residence time (MRT) between the gentamicin Cia and the 2 other components were found. The total body clearance (CL) of gentamicin C1a was 1.62 +/- 0.50 ml/min x kg and similar to the glomerular filtration rate (GFR) reported for horses. The CL of gentamicin C1 and C2 were 1.03 +/- 0.08 ml/min x kg and 1.1...
Belgrave RL, Hines MT, Keegan RD, Wardrop KJ, Bayly WM, Sellon DC.The development of ultrapurified hemoglobin-based oxygen carriers has eliminated many problems associated with whole-blood transfusions in other species. We hypothesized that the administration of polymerized ultrapurified bovine hemoglobin (PUBH) would result in improved hemodynamic parameters in ponies with normovolemic anemia without adverse effects on renal function or coagulation times. Normovolemic anemia was induced in 6 healthy adult ponies. Over a 3-day period, at least 45 mL/kg of whole blood was withdrawn from each pony until a target PCV of <12% was attained. Plasma was separate...
Bousquet-Melou A, Bernard S, Schneider M, Toutain PL.Marbofloxacin is a fluoroquinolone antibiotic expected to be effective in the treatment of infections involving gram-negative and some gram-positive bacteria in horses. In order to design a rational dosage regimen for the substance in horses, the pharmacokinetic properties of marbofloxacin were investigated in 6 horses after i.v., subcutaneous and oral administration of a single dose of 2 mg/kg bwt and the minimal inhibitory concentrations (MIC) assessed for bacteria isolated from equine infectious pathologies. The clearance of marbofloxacin was mean +/- s.d. 0.25 +/- 0.05 l/kg/h and the termi...
Carretero M, Rodríguez C, San Andrés MI, Forés P, de Lucas JJ, Nieto J, Waxman S, San Andrés MD, González F.The pharmacokinetic behaviour of marbofloxacin, a new fluoroquinolone antimicrobial agent developed exclusively for veterinary use, was studied in mature horses (n = 5) after single-dose i.v. and i.m. administrations of 2 mg/kg bwt. Drug concentrations in plasma were determined by high performance liquid chromatography (HPLC) and data obtained were subjected to compartmental and noncompartmental kinetic analysis. This compound presents a relatively high volume of distribution (V(SS) = 1.17 +/- 0.18 l/kg), which suggests good tissue penetration, and a total body clearance (Cl) of 0.19 +/- 0.042...
Oikawa M, Shiga J.To evaluate the effects of endotoxin on the morphology of the equine mesenteric vasculature, each of two thoroughbred horses were given two intravenous injections (24 h apart) of a sublethal dose of endotoxin (10 microg/kg). Each injection produced results similar to those of clinical cases of equine colic with obstructive nature of the loop of bowel: diarrhoea within 2 h after administration, followed by cessation of both faecal excretion and sounds of intestinal peristalsis. The most prominent morphological change was the development of moniliform appearance of small mesenteric arteries, in ...
Davis JL, Gardner SY, Jones SL, Schwabenton BA, Papich MG.The properties of azithromycin suggest that it may be an alternative to erythromycin for treatment of Rhodococcus equi pneumonia in foals. To investigate this possibility, the disposition of azithromycin in plasma, polymorphonuclear leukocytes (PMN), and alveolar cells was examined after a single administration in foals. Azithromycin suspension was administered orally (p.o.) at a dose of 10 mg/kg to five healthy 2-3-month-old foals. Two weeks later, azithromycin for injection was administered by intravenous (i.v.) infusion at a dose of 5 mg/kg to the same foals. Plasma samples were collected a...
Smith GW, Constable PD, Foreman JH, Eppley RM, Waggoner AL, Tumbleson ME, Haschek WM.To determine whether cardiovascular dysfunction is evident in horses with leukoencephalomalacia experimentally induced by administration of fumonisin B1. Methods: 11 healthy horses of various breeds (body weight, 252 to 367 kg). Methods: Horses were randomly assigned to 3 groups and administered fumonisin B1 daily. Horses received IV injections of 0 (control horses; n = 4), 0.01 (3), or 0.20 mg (4) of fumonisin B1/kg for 7 to 28 days. Horses were examined daily for evidence of neurologic disease. When neurologic signs consistent with leukoencephalomalacia were evident, horses were anesthetized...
Peck KE, Matthews NS, Taylor TS, Mealey KL.To compare serum disposition of sulfamethoxazole and trimethoprim after IV administration to donkeys, mules, and horses. Methods: 5 donkeys, 5 mules, and 3 horses. Methods: Blood samples were collected before (time 0) and 5, 15, 30, and 45 minutes and 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, and 24 hours after IV administration of sulfamethoxazole (12.5 mg/kg) and trimethoprim (2.5 mg/kg). Serum was analyzed in triplicate with high-performance liquid chromatography for determination of sulfamethoxazole and trimethoprim concentrations. Serum concentration-time curve for each ani...
Scheuch BC, Van Hoogmoed LM, Wilson WD, Snyder JR, MacDonald MH, Watson ZE, Steffey EP.To establish the route of infusion (IV or intraosseous) that results in the highest concentration of amikacin in the synovial fluid of the tibiotarsal joint and determine the duration of peak concentrations. Methods: 21 horses. Methods: Regional perfusion of a limb on 15 horses was performed. Amikacin sulfate was infused into the saphenous vein or via intraosseous infusion into the distal portion of the tibia (1 g in 56 ml of lactated Ringer's solution) or proximal portion of the metatarsus (1 g of amikacin in 26 ml of lactated Ringer's solution). Amikacin concentrations were measured in seque...
Ohmura H, Hiraga A, Aida H, Kuwahara M, Tsubone H.To investigate the effects of repeated atropine injection on heart rate (HR) variability in resting Thoroughbred horses, two microg/ kg of atropine as parasympathetic nervous blockade was injected intravenously every 6 min to a total of 8 microg/kg after intravenous administration of 0.2 mg/kg of propranolol as sympathetic nervous blockade. We recorded electrocardiograms and obtained the HR, then evaluated variation in HR from the power spectrum in terms of low frequency (LF, 0.01-0.07 Hz) power and high frequency (HF, 0.07-0.6 Hz) power. Administration of atropine decreased parasympathetic ne...
Hallebeek JM, Beynen AC.A fat-free liquid diet was formulated to be administered by nasogastric tube as therapy for hyperlipaemia in ponies. The liquid diet provided energy, protein, minerals, trace elements, and vitamins in accordance with the requirements of ponies. As sole source of nutrition, the liquid diet fully counteracted fasting-induced hyperlipaemia in two healthy ponies. The liquid diet was also used in hyperlipaemic patients, but only in combination with conventional therapy, consisting of intravenous administration of glucose, insulin, and heparin. Although no patients were treated with the liquid diet ...
Lankveld DP, Ensink JM, van Dijk P, Klein WR.Thrombophlebitis is a well-known complication of the use of long-term in-dwelling catheters. In humans, catheter material has been shown to strongly influence the occurrence of thrombophlebitis. In the horse, the influence of catheter material has been studied in healthy experimental animals, but information on the relative importance of this factor is lacking. To investigate which factors have most impact on the frequency of jugular vein thrombosis in post-surgical colic horses, a clinical study was performed on 38 animals. Horses were randomly divided into two groups. In one group a polytetr...
Jacks S, Giguère S, Gronwall PR, Brown MP, Merritt KA.To determine the pharmacokinetics of azithromycin and its concentration in body fluids and bronchoalveolar lavage cells in foals. Methods: 6 healthy 6- to 10-week-old foals. Methods: Azithromycin (10 mg/kg of body weight) was administered to each foal via i.v. and intragastric (i.g.) routes in a crossover design. After the first i.g. dose, 4 additional i.g. doses were administered at 24-hour intervals. A microbiologic assay was used to measure azithromycin concentrations in serum, peritoneal fluid, synovial fluid, pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. Resul...
McClure JT, DeLuca JL, Lunn DP, Miller J.The purpose of this study was to evaluate the ability of an equine plasma product i.v. and a concentrated serum product i.v. to deliver antibodies to 46 foals with failure of passive transfer (FPT). Treatment of FPT was as per manufacturers recommendations, using plasma (950 ml/unit) or a concentrated serum product (250 ml/unit). Significant variables affecting the 3 day post-transfusion serum immunoglobulin G (IgG) concentration of foals included body weight, pretransfusion IgG concentration, number of product units transfused, foaling season and product administered. Plasma treatment had a g...
Jansson A, Lindholm A, Dahlborn K.The effect of a temporary increase in plasma aldosterone concentration on Na(+), K(+), and water balance was investigated in four horses. Aldosterone was injected intravenously for 6 h at 20-min intervals (total 5.4 microg/kg body wt). Samples were taken for 24 h before, during, and for 48 h after the treatment. Aldosterone treatment reduced the Na(+) loss via urine and feces by 99 and 72%, respectively, later followed by a marked increase in Na(+) excretion by both pathways. During the first 6 h after the treatment, fecal K(+) excretion was elevated, and the plasma K(+) concentration was lowe...
McDonnell SM.This study is part of ongoing work toward developing pharmacological methods for enhancing and inducing ejaculation in stallions with ejaculatory dysfunction or disabilities that interfere with normal breeding behavior. The objective was to evaluate a treatment regimen involving oral imipramine followed by intravenous xylazine that, in uncontrolled field clinical trials, had shown promise for a higher rate of ejaculation and fewer side effects using a more easily obtained and administered form of imipramine. Eight stallions each underwent eight trials in which treatment consisted of imipramine...
Dart A, Perkins N, Dowling , Batterham T, Livingston C, Hodgson D.To evaluate the effects of three different doses of sodium pentosan polysulphate (PPS) on haematological and haemostatic variables in adult horses. Methods: Eight adult standardbred horses were used. All horses received a single injection of 0, 3, 6, and 10 mg/kg of PPS at the beginning of each treatment week for 4 weeks so that by the end of the study all horses had received all four doses of PPS. Blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 168 h after each weekly injection of PPS. Variables measured were packed cell volume, haemoglobin, red blood cell count, mean cor...
Bony S, Durix A, Leblond A, Jaussaud P.The toxicokinetics of ergovaline (an ergopeptine mycotoxin present in some grasses infected with endophytic fungus of the genus Neotyphodium) were studied after intravenous administration of a single dose of 15 microg/kg bwt in four gelding horses. Plasma ergovaline concentrations were measured by high performance liquid chromatography, and the kinetic data were described by a three-compartment model. The elimination half-life and the total clearance of ergovaline were found to be 56.83 +/- 13.48 min and 0.020 +/- 0.004 L/min x kg, respectively. According to the toxicological data previously r...
Latimer FG, Colitz CM, Campbell NB, Papich MG.To determine the pharmacokinetics of fluconazole in horses. Methods: 6 clinically normal adult horses. Methods: Fluconazole (10 mg/kg of body weight) was administered intravenously or orally with 2 weeks between treatments. Plasma fluconazole concentrations were determined prior to and 10, 20, 30, 40, and 60 minutes and 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, and 72 hours after administration. A long-term oral dosing regimen was designed in which all horses received a loading dose of fluconazole (14 mg/kg) followed by 5 mg/kg every 24 hours for 10 days. Fluconazole concentrations were determined i...
Hatfield CL, McDonell WN, Lemke KA, Black WD.To determine the pharmacokinetics and toxic effects associated with IV administration of lithium chloride (LiCl) to conscious healthy horses. Methods: 6 healthy Standardbred horses. Methods: Twenty 3-mmol boluses of LiCl (0.15 mmol/L) were injected IV at 3-minute intervals (total dose, 60 mmol) during a 1-hour period. Blood samples for measurement of serum lithium concentrations were collected before injection and up to 24 hours after injection. Behavioral and systemic toxic effects of LiCl were also assessed. Results: Lithium elimination could best be described by a 3-compartment model for 5 ...
Chu KK, Cohen ND, Stanley SD, Wang N.To estimate the probability of concurrently exceeding thresholds for plasma concentration of furosemide and urine specific gravity after IV administration of furosemide in horses. Methods: 12 mature healthy Thoroughbred (n = 6) or Quarter Horse (6) mares. Methods: Venous blood was collected from each horse prior to and 0.25, 0.5, 0.75, 1, 2, 3, 4, 4.5, 5, and 6 hours after IV administration of 250 mg (first experiment) or 500 mg (second experiment) of furosemide. Urine was collected hourly between 1 and 6 hours after administration of furosemide at both doses. Concentrations of furosemide were...
Bettschart-Wolfensberger R, Bowen MI, Freeman SL, Feller R, Bettschart RW, Nolan A, Clarke KW.To determine cardiopulmonary effects of total IV anesthesia with propofol and medetomidine in ponies and effect of atipamezole on recovery. Methods: 10 ponies. Methods: After sedation was induced by IV administration of medetomidine (7 microg/kg of body weight), anesthesia was induced by IV administration of propofol 12 mg/kg) and maintained for 4 hours with infusions of medetomidine (3.5 microg/kg per hour) and propofol 10.07 to 0.11 mg/kg per minute). Spontaneous respiration was supplemented with oxygen. Cardiopulmonary measurements and blood concentrations of propofol were determined during...
Meyer GA, Lin HC, Hanson RR, Hayes TL.This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to admi...
Hagedorn HW, Meiser H, Zankl H, Schulz R.The tricyclic antidepressant doxepin, representing a 5:1 mixture of trans- and cis-isomers, owns tranquilizing properties. This compound has been associated with illicit medication of racing horses, and therefore should be considered in doping control. Because analysis of doxepin in equine body fluids has not been documented in the literature, a highly sensitive analytical method was developed to individually monitor the doxepin isomers in blood and urine of horses by the use of gas chromatography/mass spectrometry. Following a dose of 1 mg doxepin-HCl/kg intravenously (i.v.), both the isomers...
Butt TD, Bailey JV, Dowling PM, Fretz PB.The purpose of this study was to compare the synovial fluid concentrations and pharmacokinetics of amikacin in the equine limb distal to the carpus following intraosseous and intravenous regional perfusion. The front limbs of 6 horses were randomly assigned to either intraosseous or intravenous perfusion. A tourniquet was placed distal to each carpus and the limb perfused with 500 mg of amikacin. Systemic blood samples and synovial fluid samples were collected over 70 min from the distal interphalangeal (DIP) joint, metacarpophalangeal joint, and digital flexor sheath. The tourniquet was remov...
Gangl M, Grulke S, Detilleux J, Caudron I, Serteyn D.Forty-eight horses subjected to elective surgery were randomly assigned to three groups of 16 horses. After premedication with 0.1 mg/kg acepromazine intramuscularly and 0.6 mg/kg xylazine intravenously, anaesthesia was induced either with 2 g thiopentone in 500 ml of a 10 per cent guaifenesin solution, given intravenously at a dose of 1 ml/kg (group TG), or with 100 mg/kg guaifenesin and 2.2 mg/kg ketamine given intravenously (group KG), or with 0.06 mg/kg midazolam, and 2.2 mg/kg ketamine given intravenously (group KM). Anaesthesia was maintained with isoflurane. The mean (sd) end tidal isof...
Tetens J, Eades SC, Hosgood G, Koch CE, Moore RM.To characterize alterations in systemic and local colonic hemodynamic variables associated with IV infusion of ATP-MgCl2 in healthy anesthetized horses. Methods: 12 adult horses. Methods: Six horses were given ATP-MgCl2, IV, beginning at a rate of 0.1 mg of ATP/kg of body weight/min with incremental increases until a rate of 1.0 mg/kg/min was achieved. The remaining 6 horses were given an equivalent volume of saline (0.9% NaCl) solution over the same time period. Colonic and systemic hemodynamic variables and colonic plasma nitric oxide (NO) concentrations were determined before, during, and a...
Manohar M, Goetz TE, Rothenbaum P, Humphrey S.The present study was carried out to examine whether pentoxifylline administration to horses premedicated with frusemide would attenuate the exercise-induced pulmonary arterial, capillary and venous hypertension to a greater extent than frusemide alone, thereby affecting the occurrence of exercise-induced pulmonary haemorrhage (EIPH). Using established techniques, we determined right heart and pulmonary vascular pressures in 6 healthy, sound Thoroughbred horses at rest and during exercise performed at maximal heart rate at a workload of 14 m/s on 3.5% uphill grade in the control (no medication...
Muir WW, Sams RA, Hubbell JA, Hinchcliff KW, Gadawski J.To determine the effects of IV administration of enalaprilat on cardiorespiratory and hematologic variables as well as inhibition of angiotensin converting enzyme (ACE) activity in exercising horses. Methods: 6 adult horses. Methods: Horses were trained by running on a treadmill for 5 weeks. Training was continued throughout the study period, and each horse also ran 2 simulated races at 120% of maximum oxygen consumption. Three horses were randomly selected to receive treatment 1 (saline [0.9% NaCl] solution), and the remaining 3 horses received treatment 2 (enalaprilat; 0.5 mg/kg of body weig...
Gardner SY, Papich MG.The pharmacokinetics of cefepime, a new fourth generation cephalosporin with enhanced antibacterial activity, was examined in neonatal foals and adult dogs. Cefepime was administered intravenously (i.v.) at a dose of 14 mg/kg to five neonatal foals and six adult dogs. Blood samples were collected in both groups of animals and plasma cefepime concentrations measured by reverse-phase high-performance liquid chromatography (HPLC). Cefepime concentrations in both groups of animals were described by a two-compartment pharmacokinetic model with elimination half-lives of 1.65 and 1.09 h for the foal ...
Nolen-Walston RD.Large animal species in states of shock can require particularly high flow rates for volume resuscitation and the ability to deliver adequate volumes rapidly may be a rate-limiting step. The objective of this study was to determine the maximum flow rates of common combinations of IV catheter, extension set, and fluid administration sets. Methods: University veterinary teaching hospital. Methods: In vitro experimental study. Methods: Maximum flow rates were measured using combinations of 4 IV catheters (3 14-Ga and a single 10-Ga), 2 IV catheter extension sets (small bore and large bore), and 2...
Hamamoto-Hardman BD, Steffey EP, McKemie DS, Kass PH, Knych HK.Meperidine is a synthetic opioid that belongs to the phenylpiperidine class and is a weak mu receptor agonist. In horses there are a limited number of published studies describing the analgesic effects of systemically administered meperidine in horses. The objective of this study was to describe the pharmacokinetics, behavioral and physiologic effects and effect on thermal threshold of three doses of intravenously administered meperidine to horses. Eight University owned horses (four mares and four geldings, aged 3-8 years were studied using a randomized balanced 4-way cross-over design. Hors...
Romão FT, Pereira PF, Flaiban KK, Dearo AC, Fernandes TM, Lisbôa JA.Treatment of metabolic acidosis using sodium bicarbonate solutions is safe when blood gas analysis is available. The evidence that solutions containing metabolisable buffers can be used as an alternative for treatment of metabolic acidosis in horses is of practical interest. Objective: To investigate the safety and efficacy of a polyionic solution containing 84 mEq/l of lactate (L84) for the correction of induced hyperchloraemic metabolic acidosis. Methods: Non-randomised crossover design. Methods: Five healthy, adult, crossbred horses were used. A solution containing 100 mmol/l of HCl was inf...
Guillaume D, Bruneau B, Briant C.The effects of two GnRH antagonists were tested in order to delay and/or synchronise ovulation in mares. Five mares received Antarelix (0.01 mg.kg(-1)), 5 mares received Cetrorelix (the same dose), 5 mares (control mares) received the vehicle intravenously, twice daily, for 8 days from the day the largest follicle reached 22 mm following prostaglandin administration. Ovulation was postponed in all mares injected with Antarelix (19.4 +/- 1.2 days after the beginning of the treatment) and in 2/5 mares injected with Cetrorelix (20 +/- 1 days) vs. 6.2 +/- 0.4 days in control mares. During the trea...
Gardner SY, Atkins CE, Sams RA, Schwabenton AB, Papich MG.The pharmacokinetics of enalapril (0.5 mg/kg i.v.) and the pharmacodynamics of enalapril (0.5 mg/kg PO) in 5 mares were investigated. After single i.v. dosing, concentrations of enalapril and enalaprilat, its active metabolite, were measured. Two weeks later, enalapril was administered by nasogastric tube. Potassium, creatinine, blood urea nitrogen (BUN), enalapril, and enalaprilat concentrations and angiotensin converting enzyme (ACE) activity were measured in serum. In addition, heart rate, blood pressure, digital venous blood gases, and lactate were measured. Two weeks later, enalapril was ...
Wilson KE, Bogers SH, Council-Troche RM, Davis JL.To determine the effects of general anesthesia on the safety and efficacy of co-administered potassium penicillin G (PEN) and gentamicin (GENT) in horses. Methods: Nonrandomized crossover. Methods: Six adult, Thoroughbred horses. Methods: Horses were administered PEN (22 000 IU/kg IV) and GENT (6.6 mg/kg IV). Plasma samples were collected over a 6 h period and synovial fluid was collected at 30 min and 6 h respectively. Drug administration and sample collection protocols were repeated after at least a 48 hour washout period and induction of anesthesia using xylazine/ketamine and main...
Dias DCR, Ribeiro Filho JD, Viana RB, Bittencourt TCC, Dantas FTDR, Teixeira RBC, Di Filippo PA, Manso Filho HC, Alves SR, Santos PVM, Moreira NS.Continuous flow enteral fluid therapy with isotonic and hypotonic enteral electrolyte solutions are as safe and effective as intravenous fluid therapy. The aim of this study was to carry out a comparative assessment between continuous flow enteral and intravenous (IV) fluid therapy in adult experimentally dehydrated horses. Six experimentally dehydrated adult mares were used in a study carried out in a 6 × 3 crossover design, which each animal received three different treatments (isotonic enteral fluid therapy-EsISO, hypotonic enteral fluid therapy-EsHYPO and intravenous fluid therapy with La...
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...
Abu-Basha EA, Bani Ismail Z, Ababneh MM, Hamzeh E, Gehring R.This study was designed to investigate the safety and pharmacokinetic (PK) profile of tildipirosin in horses after intravenous (i.v.) and subcutaneous (s.c.) injection of a single dose at 4 mg/kg of body weight (b.w.). A total of 12 healthy mixed breed horses were used in the study. Horses were monitored for systemic and local adverse effects, and whole blood samples were collected for hematology and plasma biochemistry analysis at time (0) and at 6, 24, and 72 h after drug administration. For PK analysis, blood samples were collected at pre-determined times before and after tildipirosin adm...
Luna SP, Taylor PM, Bloomfield M.To investigate the effects of inhalation and total IV anesthesia on pituitary-adrenal activity in ponies. Methods: 9 healthy ponies: 5 geldings and 4 mares. Methods: Catheters were placed in the cavernous sinus below the pituitary gland and in the subarachnoid space via the lumbosacral space. After 72 hours, administration of acepromazine was followed by induction of anesthesia with thiopentone and maintenance with halothane (halothane protocol), or for the IV protocol, anesthesia induction with detomidine and ketamine was followed by maintenance with IV infusion of a detomidine-ketamine-guaif...
Bettschart-Wolfensberger R, Taylor PM, Sear JW, Bloomfield MR, Rentsch K, Dawling S.To examine the physiologic and pharmacokinetic effects of a technique of total intravenous anesthesia in ponies. Methods: 6 healthy ponies. Methods: Ponies were premedicated with acepromazine (0.03 mg/kg of body weight, IV) and xylazine (1.0 mg/kg, IV). Two minutes later, anesthesia was induced with ketamine (2.0 mg/kg, IV) followed by climazolam (0.2 mg/kg, IV). Anesthesia was maintained for 120 minutes by an infusion of climazolam (0.4 mg/kg/h) and ketamine (6.0 mg/kg/h). Oxygen (5 L/min) was supplemented. 20 minutes after the infusion was stopped sarmazenil (0.04 mg/kg, IV) was administered...
Baker SJ, Gerring EL.We investigated the effects of a range of IV administered doses of omeprazole (0.125 to 2.0 mg/kg of body weight) on gastric pH (monitored by indwelling electrode) and plasma gastrin concentration, compared with those of IV administered ranitidine (1.0 mg/kg) in 4 Welsh mountain-type ponies. Pharmacokinetic variables of IV administered omeprazole also were examined. Episodes of high gastric pH in the basal state obscured the effect of acid suppression on intragastric pH; however, omeprazole induced dose-dependent increase in mean gastric pH (P < 0.01) during the 11 hours after its administr...
Geimer TR, Ekström PM, Ludders JW, Erichsen DF, Gleed RD.The haemodynamic effects of hyoscine-N-butylbromide (0.30 mg/kg, intravenously) were studied in eight adult ponies in a blinded two-period crossover experiment with repeated measures. Values for heart rate were 63%, 48% and 13% greater than control values at 1, 16 and 46 min, respectively, after administration of hyoscine-N-butylbromide. Cardiac output increased by 16% at 16 min after drug injection. Mean right atrial pressure was decreased by 79%, 63%, 45% and 52% at 1, 16, 46 and 61 min, respectively, after drug administration. Stroke volume was decreased by 32% at 1 min and pulmonary arteri...
Gozalo-Marcilla M, Moreira da Silva R, Pacca Loureiro Luna S, Rodrigues de Oliveira A, Werneck Fonseca M, Peporine Lopes N, Taylor PM, Pelligand L.The alpha(α) -agonist detomidine is used for equine sedation with opioids such as methadone. We retrieved the data from two randomized, crossover studies where detomidine and methadone were given intravenously alone or combined as boli (STUDY 1) (Gozalo-Marcilla et al., 2017, Veterinary Anaesthesia and Analgesia, 2017, 44, 1116) or as 2-hr constant rate infusions (STUDY 2) (Gozalo-Marcilla et al., 2019, Equine Veterinary Journal, 51, 530). Plasma drug concentrations were measured with a validated tandem Mass Spectrometry assay. We used nonlinear mixed effect modelling and took pharmacokinetic...
Deutsch J, Ekiri A, de Vries A.To compare alfaxalone as continuous intravenous (IV) infusion with intermittent IV injections for maintenance of anaesthesia in ponies undergoing castration. Methods: Prospective, randomized, 'blinded' clinical study. Methods: A group of 33 entire male Welsh ponies undergoing field castration. Methods: After preanaesthetic medication with IV detomidine (10 μg kg) and butorphanol (0.05 mg kg), anaesthesia was induced with IV diazepam (0.05 mg kg) followed by alfaxalone (1 mg kg). After random allocation, anaesthesia was maintained with either IV alfaxalone 2 mg kg hour (group A; n ...
Jones SL, Wilson WD.Clostridium septicum was isolated by anaerobic culture of blood collected from a 3-day-old foal with hemorrhagic enteritis and signs suggestive of septicemia. The foal responded well to treatment with intravenous fluids, antibiotics, plasma, and oral gastrointestinal protectants. One month after apparent complete recovery from the septicemia and hemorrhagic enteritis, the foal was euthanized during an acute episode of colic that was caused by severe, strangulating intestinal adhesions, thought to have formed as a result of peritonitis secondary to the hemorrhagic enteritis. The value of anaero...
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...
Muir WW, Milne DW, Skarda RT.Intravenous administration of furosemide in the horse resulted in an immediate and significant decrease in right atrial pressure, pulmonary arterial pressure, pulmonary arterial wedge pressure, cardiac output, and stroke volume (P less than 0.05). There was a significant increase in total systemic vascular resistance and heart rate (P less than 0.05). There were no significant alterations in mean arterial pressure. Coincidental with these hemodynamic changes were increased urine production and associated increase in packed cell volume and total serum protein. All variables except cardiac outpu...
Hillidge CJ, Lees P.Respiratory function and acid-base variables were studied in Welsh Mountain ponies before and at predetermined times after the intravenous injection of Immobilon and Revivon.A marked depression of respiratory rate was accompanied by large reductions in arterial blood oxygen tension and saturation and the development of a mild respiratory acidosis following the injection of Immobilon. It was concluded that at least three factors contributed to the hypoxic hypoxia produced by Immobilon; the posture of lateral recumbency, the decrease in respiratory rate and the laboured character of the respirat...
Goetz TE, Munsiff IJ, McKiernan BC.The pharmacokinetic disposition of theophylline was determined by high-performance liquid chromatographic analysis of plasma samples from six healthy, adult horses following the administration of intravenous aminophylline (dosed at 9.94 mg/kg as theophylline), immediate-release aminophylline tablets (dosed at 9.94 mg/kg as theophylline), and sustained-release theophylline tablets (dosed at 20 mg/kg). The elimination rate constant (lambda z), apparent volume of distribution (Vz), and clearance (Cl) determined by compartmental analysis of the intravenous data were 0.07 +/- 0.01 h-1, 0.80 +/- 0.0...
Martins FC, Keating SC, Clark-Price SC, Schaeffer DJ, Lascola KM, DiMaio Knych H.To determine the physiologic and behavioral effects and pharmacokinetic profile of hydromorphone administered intravenously (IV) to horses. Methods: Prospective, randomized, crossover study. Methods: A group of six adult healthy horses weighing 585.2 ± 58.7 kg. Methods: Each horse was administered IV hydromorphone (0.025 mg kg; treatment H0.025), hydromorphone (0.05 mg kg; treatment H0.05) or 0.9% saline in random order with a 7 day washout period. For each treatment, physiologic, hematologic, abdominal borborygmi scores and behavioral data were recorded over 5 hours and fecal output was tota...
Sweeney RW, Reef VB, Reimer JM.Nine horses with (naturally acquired) congestive heart failure were treated with 2.2 micrograms of digoxin/kg of body weight by the IV route, followed by 11 micrograms/kg administered orally every 12 hours thereafter. Furosemide was administered IV concurrently with IV administered digoxin every 12 hours. Serum concentration of digoxin was measured after the first (IV) and seventh (orally administered) dose. After IV administration, digoxin disposition was described by a 2-compartment model, with a rapid distribution phase (t1/2 alpha = 0.17 hour), followed by a slower elimination phase (beta ...
Fielding CL, Magdesian KG.Hypertonic saline solution (7.2%) (HSS) can quickly replace intravascular volume deficits. HSS more recently has been advocated in the treatment of traumatic brain injury, but its use in dehydrated patients remains controversial. Objective: Hypertonic saline solution will show a significant improvement in both clinical and laboratory hydration parameters as compared to isotonic (0.9%) saline solution (ISS). Methods: Endurance horses eliminated from the 2009 Western States 100-mile (220-km) endurance ride and requiring IV fluid therapy were eligible for enrollment in the study. Methods: Twenty-...
Muir WW, Sams RA, Hubbell JA, Hinchcliff KW, Gadawski J.To determine the effects of IV administration of enalaprilat on cardiorespiratory and hematologic variables as well as inhibition of angiotensin converting enzyme (ACE) activity in exercising horses. Methods: 6 adult horses. Methods: Horses were trained by running on a treadmill for 5 weeks. Training was continued throughout the study period, and each horse also ran 2 simulated races at 120% of maximum oxygen consumption. Three horses were randomly selected to receive treatment 1 (saline [0.9% NaCl] solution), and the remaining 3 horses received treatment 2 (enalaprilat; 0.5 mg/kg of body weig...
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...
Wood T, Weckman TJ, Henry PA, Chang SL, Blake JW, Tobin T.Our investigation of the urine of grazing horses at the University of Kentucky shows that the mean pH level is about 7.9, and if their diet is supplemented with grain, it is about 7.4. There appears to be no significant effect of time of day or year on urine pH levels in horses. However, horses taken from pasture and supplemented with grain in a stalled environment show a slight decrease in urine pH. Additionally, we investigated the effects of storage on pH levels. Equine urine samples appear to be quite stable with regard to pH for 48h, but then show a marked increase. Urine pH can have a gr...
Diez Bernal S, Studer N, Thormann W, Spadavecchia C, Levionnois O.To evaluate the effect of a romifidine infusion on antinociception and sedation, and to investigate its relationship with plasma concentration. Methods: Prospective, experimental, nonrandomized trial. Methods: A total of 10 healthy adult warmblood horses. Methods: Romifidine (loading dose: 0.08 mg kg, infusion: 0.03 mg kg hour) was administered intravenously over 120 minutes. Romifidine plasma concentrations were determined by capillary electrophoresis. Sedation quality and nociceptive thresholds were evaluated at regular time points before, during and after romifidine administration. The noci...
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...
Snow DH, Baxter P, Whiting B.The pharmacokinetics of meclofenamic acid were studied in Thoroughbred horses and in ponies. After intravenous (i.v.) administration of either 2 mg/kg or 4 mg/kg sodium meclofenamate the elimination half-life was of the order of 0.9 h while the volume of distribution was found to be 0.128 litre/kg. Elimination was in accordance with a one-compartment model. Following oral administration of either meclofenamic acid (4 mg/kg) or sodium meclofenamate (4 mg/kg) a much longer terminal half-life than that calculated for Kel from i.v. data was found. This anomaly indicated that the 'flip-flop' phenom...
Jernigan AD, Wilson RC, Booth NH, Hatch RC, Akbari A.In steers, horses and dogs, the comparative pharmacokinetics of yohimbine were determined using model-independent analysis. The intravenous dose of yohimbine was 0.25 mg/kg of body weight in steers, 0.075 or 0.15 mg/kg in horses, and 0.4 mg/kg in dogs. The mean residence time (+/- SD) of yohimbine was 86.7 +/- 46.2 min in steers, 106.2 +/- 72.1 to 118.7 +/- 35.0 min in horses, and 163.6 +/- 49.7 min in dogs. The mean apparent volume of distribution of yohimbine at steady state was 4.9 +/- 1.4 L/kg for steers, 2.7 +/- 1.0 to 4.6 +/- 1.9 L/kg for horses, and 4.5 +/- 1.8 L/kg for dogs. The total ...
