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.
Brumbaugh GW, Thomas WP, Enos LR, Kaneko JJ.Digoxin was administered orally and intravenously to seven healthy adult mares and geldings in two separate trials. At a dose of 44 microgram digoxin/kg body weight, the oral study was characterized by an absorption phase with a mean (+/- 1 standard deviation) peak serum digoxin concentration of 2.21 ng/ml (+/- 0.45) at a mean of 2.29 h (+/- 1.52) after administration. A second rise in serum digoxin concentration started about 6-8 h after administration and extended to about 20 h after administration. The mean bioavailability (F) was 23.38% (+/- 5.96). At a dose of 22 microgram digoxin/kg body...
Roberts MC, Seawright AA.Colic was induced in horses and ponies following topical or intravenous (iv) administration of amitraz, a formamidine acaricide. The condition was characterised by rapid cessation of intestinal sounds, stasis, extensive impaction and tympany throughout the large colon. Three animals that were necropsied had a faecalith obstructing the proximal small colon aboral to marked colonic impaction. A reproducible and reversible impaction colic syndrome could be induced by an iv injection of 1 mg amitraz/kg body weight in solvent. There were immediate central nervous system and intestinal signs. Large ...
Thijssen HH, van den Bogaard AE, Wetzel JM, Maes JH, Muller AP.The pharmacokinetics of racemic warfarin were studied in 6 adult horses. After IV administration, the plasma concentration of warfarin showed a biphasic decline in time. Analysis of the data, according to 2-compartment kinetics, revealed the following constants: biological half-life was 13.3 hours, apparent volume of distribution was 0.46 L X kg-1, body clearance was 25.3 ml X hour-1 X kg-1. Warfarin was bound (91.5%) to plasma proteins. Unchanged warfarin was not detected in the urine. Absorption from the gastrointestinal tract was almost complete. Concentrations of warfarin in tissue were ex...
Snow DH, Douglas TA.The absorption characteristics of a new paste preparation of phenylbutazone were studied in ponies and thoroughbreds. The results suggested that at a similar dose rate of 5 mg/kg greater bioavailability results from the paste than from a powder preparation. Delivery of an accurate dosage of the paste was not possible using the multidose applicator. Repeated administration of the paste preparation (5 mg/kg twice daily) indicated that it is more toxic to both ponies and thoroughbreds than a powder preparation. In addition to the toxic manifestations previously reported, a neutropenia developed d...
Kowalczyk DF, Beech J.The pharmacokinetics of the anti-convulsant phenytoin were investigated in clinically healthy horses after oral (p.o.) and intravenous (i.v.) administration. A single dose of phenytoin (8.8 mg/kg body weight) was given i.v. as a bolus to nine horses and one horse received 13.2 mg/kg. A two-compartment open model was used to describe the disposition of phenytoin. Four of the horses that received an i.v. dose (three at 8.8 mg/kg and one at 13.2 mg/kg) were then given the same dose 3 days later by the oral route. Phenytoin achieved a peak concentration in serum within 1-4 h after p.o. administrat...
Hartikka P, Dahlbom M, Westermarck H.In four training stables five trotter horses of the Finnish coldblooded breed and seven warmblooded trotters were treated with a ferrissaccharin preparation (Hippiron, Hausmann) intravenously. A short increase in heart frequency after the injection was noted. The cold solution injections, less than + 15 degrees C, may cause dangerous reactions. All horses showed an enhanced appetite, a substantially livier habitus after treatment.
Chay S, Woods WE, Rowse K, Nugent TE, Blake JW, Tobin T.Studies were undertaken to determine blood levels of furosemide in horses after 0.5- and 1.0-mg/kg doses administered iv. Analyses indicated that the pharmacokinetic parameters were dose independent and best described by a three-compartment open model. The alpha-, beta-, and gamma-phase half-lives of 5.6, 22.3, and 158.5 min, respectively, were observed after the 0.5-mg/kg dose. Similarly, the respective half-lives after the 1.0-mg/kg dose were 5.8, 24.1, and 177.2 min. After a 0.5-mg/kg dose of furosemide, population frequency distributions were evaluated at 1 hr and 4 hr post-drug administra...
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...
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...
Brightman AH, Manning JP, Benson GJ, Musselman EE.Schirmer I tear tests were conducted on 14 horses. The test was performed before and after IV administration of xylazine hydrochloride, during maintenance anesthesia with halothane in oxygen, and 3 hours after discontinuation of anesthesia. Xylazine hydrochloride did not decrease tear production from the mean base-line value of 23.94 +/- 5.23 mm/min after its IV administration. Tear production was decreased to mean values of 15.57 +/- 4.29 mm/min at 30 minutes and 13.84 +/- 4.25 mm/min at 60 minutes during the maintenance of halothane anesthesia. Three hours after anesthesia was discontinued, ...
Dyson S.Thirty cases of peritonitis, in which the diagnosis was based on a peritoneal fluid white blood cell count in excess of 10 x 10(9)/litre, are described. Colic, ileus, pyrexia, weight loss and diarrhoea were common presenting signs. Treatments included intravenous fluids, anti-inflammatory analgesics, broad spectrum antibiotics and anthelmintics. Duration of treatment was determined by the clinical condition of the horse and sequential analyses of the peritoneal fluid and the haemogram. In the majority of cases the primary cause of peritonitis was not accurately determined, but 21 horses (70 pe...
Greene EW, Woods WE, Tobin T.Caffeine (4 mg/kg) was given by rapid IV injection to 4 horses. Plasma concentrations of the drug peaked at 10 micrograms/ml and decreased rapidly at first, and then more slowly, with an apparent beta-phase half-life of 18.2 hours. Urinary concentrations of caffeine were remarkably consistent at about 3 times plasma values of the drug. Caffeine was detectable in both plasma and urine of the horses for up to 9 days after dosing. After oral administration, caffeine was absorbed poorly with an apparent bioavailability of 39%. Although blood concentrations of caffeine peaked rapidly after oral adm...
Love DN, Rose RJ, Martin IC, Bailey M.Twelve geldings were used to evaluate serum levels of penicillin following the intravenous (iv) and intramuscular (im) injection of benzylpenicillin, im procaine penicillin and im fortified benzathine penicillin, at a variety of dose rates. Blood samples were collected up to 7 h after iv and im benzylpenicillin, up to benzathine penicillin. Results were analysed using an analysis of variance and regression analyses were used to calculate the time taken for the serum penicillin concentration to decline to 0.5 micrograms/ml. As a result of the experiments the following dosage regimes could be re...
Wolter R, Durix A, Letourneau JC, Carcelen M, Henry N.One pony has been subjected to the intravenous injections of L-lactic acid. Two other ponies have been trained to intracaecal administration of L-lactic acid or sucrose. The obtained results show that: Intravenous injection of lactic acid increases the concentration of histamin and lactic acid, decreases the level of magnesium and reduces the pressure of carbon dioxide in the blood (the control animals and the treated animals) without the clinical symptoms of lactic acidosis. Intracaecal administration of lactic acid induces a high liberation of histamin in the caecum (the control animals and ...
Thurmon JC, Neff-Davis C, Davis LE, Stoker RA, Benson GJ, Lock TF.The effects of intravenous xylazine (1.1 mg/kg) were studied in six thoroughbred horses (five mares and a stallion). Plasma glucose concentration increased to 168% of control at 45 min and decreased to 112% of control at 180 min. Insulin had decreased to 31% of control at 15 min. Thereafter, insulin concentration increased, reaching its highest concentration at 150 min. The mechanism for these changes is not fully understood and further investigation is indicated.
Derksen FJ, Slocombe RF, Robinson NE.In standing sedated ponies, we measured dynamic lung compliance (Cdyn) and pulmonary resistance (RL) during IV infusion of various doses of histamine; this was done in a given pony 3 times at 1-week intervals between experiments. Histamine doses causing a decrease in Cdyn of 50% and 75% and an increase in RL of 300% and 600% (ED50Cdyn, ED75Cdyn, ED300RL and ED600RL, respectively) were interpolated from the histamine dose-response curves. We also measured respiratory frequency, tidal volume, minute ventilation, functional residual capacity, arterial oxygen tension, arterial carbon dioxide tensi...
Glazier DB, Littledike ET, Evans RD.In 11 crossbred ponies, hyperkalemia was induced by acute intracardiac infusion of a 0.4M solution of potassium chloride. The ECG changes noticed can be assigned to 4 stages: (1) a widening and a lowering of amplitude followed by inversion and final disappearance of the P wave; (2) an increase in the amplitude of the T wave; (3) an increase in the QRS interval, with some irregularity in the ventricular rate; and (4) periods of cardiac arrest that became terminal or were followed by ventricular fibrillation. At plasma potassium values of greater than 7.5 mM/L, the T-wave amplitude and duration ...
Parry BW, Anderson GA, Gay CC.The hypotensive effect of acepromazine maleate was related to both the dose and route of administration. The degree and duration of hypotension varied between individual horses. In general, intravenous administration produced a more rapid maximum effect than intramuscular injection and the larger the dose the longer blood pressure remained at low levels. Average systolic pressure (of 6 horses) remained significantly below control values for more than 6 h after an intramuscular injection of 0.05 mg acepromazine maleate/kg body weight. Respiratory rate was markedly decreased, with the duration, ...
Muir WW, Sams RA, Huffman RH, Noonan JS.The cardiopulmonary, behavioral, and pharmacokinetic properties of diazepam were determined in horses. Heart rate, cardiac output, mean pulmonary artery, aortic and right atrial blood pressures, respiratory rate, and arterial pH and blood gas values did not change after IV diazepam (0.05, 0.1, 0.2, 0.4 mg/kg) administration. Increasing doses of diazepam resulted in signs of muscle weakness including fixed stance, muscle fasciculations of the head, neck, and thorax muscles, ataxia, and then recumbency. Dosages of diazepam exceeding 0.2 mg/kg produced mild sedation. Behavioral changes persisted ...
Alexander F.The effect of ethacrynic acid, bumetanide, frusemide, spironolactone and anti-diuretic hormone (ADH) on the urinary and faecal excretion of water and electrolytes by ponies was studied. Ethacrynic acid, bumetanide, and frusemide given intravenously, increased urinary sodium excretion, and, excepting frusemide, decreased faecal sodium excretion. Given by stomach tube ethacrynic acid reduced urinary and faecal sodium. Bumetanide, given intravenously, spironolactone, frusemide and ADH increased urinary sodium and all except frusemide intravenously decreased faecal sodium regardless of route of ad...
Rose RJ, Kohnke JR, Baggot JD.Plasma phenylbutazone concentrations were determined for up to 12 h in 6 horses following intravenous and oral phenylbutazone administration. To evaluate the bioavailability of different oral preparations, phenylbutazone was administered in a paste as well as the traditional powder form. The effect of the state of stomach contents on the absorption of phenylbutazone was investigated by administering the paste before and after feeding; the powder was given in a small bran mash and a full feed of lucerne chaff, wheaten chaff and bran. Despite great variability among individual horses both the pa...
Ford EJ, Evans J.1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C]glucose and [2-3H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting the total entry rate fell from 1.44 +/- 0.11 (n4) to 1.19 +/- 0.12 mg/min per kg body-weight (P less than 0.01) and irreversible loss fell from 1.36 +/- 0.10 (n4) to 1.05 +/- 0.10 mg/min per kg body-weight (P...
Moore JN, Garner HE, Shapland JE, Roberts MC.The infusion (IV) of prostacyclin (PGI2) into conscious ponies resulted in systemic arterial hypotension and tachycardia. Mean systemic arterial pressure decreased from 103.3 mm of Hg to 88.5 mm of Hg when 125 ng of PGI2/kg/minute was infused, and heart rate increased from 55.0 to 102.0 beats/minute. When 208 ng of PGI2/kg/minute was infused, mean systemic arterial pressure decreased from 103.3 to 78.0 mm of Hg and heart rate increased from 55.0 to 109.3 beats/minute. There were no significant alterations in pulmonary arterial pressure, lactate, PCV, total WBC count, platelet count, serum lact...
van Dyk E, Immelman A, van Heerden JS.After isolation of Pseudomonas aeruginosa from endometrial biopsies of 6 mares they were treated with amikacin sulphate. Three were treated by intra-uterine application of the drug, in one the drug was given by intramuscular injection, in another the intravenous route was used while in the last mare simultaneous local and intravenous treatment was applied. An intra-uterine Tris-EDTA instillation preceeded the uterine amikacin instillations to aid in the breakdown of the capsule around the bacterium. Serum concentrations of amikacin were determined after intravenous and intramuscular administra...
Gronwall R, Engelking LR.The effects of several treatments and their routes of administration on the reduction of hyperbilirubinemia in 9 pony mares after a 3-day fast were studied. Treatments were as follows: glucose given at doses of 1.2, 2.4, and 3.7 mg/min/kg of body weight; refeeding the base-line diet; feeding straw; and IV administration of taurocholic acid at a dosage of 0.07 mumol/min/kg. The 3 glucose dosages were each given by 3 different routes: IV, intraduodenal, and intragastric. The smallest dosage of glucose given by IV route reduced the plasma bilirubin concentration only 7%, even though other measure...
Ballard S, Shults T, Kownacki AA, Blake JW, Tobin T.After intravenous (i.v.) injection, acepromazine was distributed widely in the horse (Vd = 6.6 litres/kg) and bound extensively (greater than 99%) plasma proteins. Plasma levels of drug declined with an alpha half-life of 4.2 min, while the beta phase or elimination half-life was 184.8 min. At a dosage level of 0.3 mg/kg acepromazine was detectable in the plasma for 8 h post dosing. The whole blood partitioning of acepromazine was 46% in the plasma phase and 54% in the erythrocyte phase. Penile prolapse was clearly evident at doses from 0.01 mg/kg to 0.4 mg/kg i.v., and the duration and extent...
Nugent TE, Combie JD, Weld JM, Burns P, Tobin T.The enkephalins are small, pentapeptide neurotransmitter molecules which have reportedly been used in racing horses. In our experiments, D-Ala2-Metenkephalinamide and leucine enkephalin were administered to horses intravenously (IV) and intracisternally (IC). Leucine enkephalin had little effect on locomotor activity by either route at doses of 0.01 mg/Kg or less. Methionine enkephalinamide, an enzyme resistant enkephalin analog, had no significant effect when given IV (0.002 and 0.008 mg/kg). Other experiments involving intracisternal dosing with this long acting form at higher levels (0.005-...
Larson VL, Stowe CM.Oxytetracycline (OTC) was administered IV to 3 clinically normal horses at a dosage of 10 mg of OTC/kg of body weight. Plasma OTC concentrations were determined at 30-minute intervals until postinjection minute (PIM) 240. At PIM 240, the mean OTC concentration in pulmonary tissue was 3.96 microgram/g of tissue (wet weight) and in renal tissue was 25.47 micrograms/g. diluted bronchial fluid had a mean concentration of 0.288 microgram of OTC/ml at PIM 240. The data demonstrated that OTC has adequate tissue distribution in horses.
Baggot JD, Love DN, Rose RJ, Raus J.The disposition kinetics and bioavailability of streptomycin, kanamycin and neomycin were determined following their administration as parenteral preparations to horses. Single doses (10 mg/kg) of each aminoglycoside were given by the intravenous (i.v.) and intramuscular (i.m.) routes and, at a later time, seven intramuscular doses were injected at 12-h intervals. The pharmacokinetic behaviour of the three aminoglycosides was similar, in that a rapid distribution phase was followed by a relatively short half-life. The half-life (mean +/- SD, n = 6) of kanamycin (1.80 +/- 0.17 h) was significan...
Doerffel A, Reinert A, Böttcher D, Winter K, Brehm W, Gittel C.Complications associated with indwelling intravenous catheters vary from minor to severe. Changes in tissue architecture and vein structure may be detectable prior to clinical alterations. The aim of the study was to characterize and compare changes in a catheterized vein and surrounding tissue by clinical and ultrasonographic examination. Microbiological infestation of catheter specimens was assessed. Methods: In this prospective, observational, clinical study 55 horses with an indwelling intravenous catheter have been included. Subsequent to catheter placement, vein and surrounding tissue we...
Reed RA, Epstein KL, Bramski JH, Diehl KA, Ryan CA.To determine the effect of xylazine on intracranial pressure (ICP) in standing compared to isoflurane-anesthetized horses. Methods: Prospective, crossover study design. Methods: University Teaching Hospital. Methods: Six adult horses donated to the University. Horses were determined to be healthy via physical examination, complete blood count, and neurological evaluation. Methods: Horses were anesthetized, maintained on isoflurane in oxygen in left lateral recumbency, and ventilated to normocapnia. Horses were instrumented for intraparenchymal measurement of ICP, invasive blood pressure, pulse...
Zertuche JM, Brown MP, Gronwall R, Merritt K.Pharmacokinetic values for flunixin meglumine (1 mg/kg of body weight) and phenylbutazone (4 mg/kg) dosages were determined after a single IV injection with and without concurrent intragastric administration of probenecid (50 mg/kg) in 6 healthy mares. Significant difference was not apparent in the pharmacokinetic values of flunixin meglumine with and without concurrent probenecid administration. Significant (P less than or equal to 0.05) increase was evident in the 12-hour mean concentration of phenylbutazone (11.45 +/- 1.66 micrograms/ml without probenecid; 14.56 +/- 1.20 micrograms/ml with ...
Kamerling SG, Cravens WM, Bagwell CA.1. Detomidine is a novel veterinary sedative analgesic which is thought to act by stimulation of alpha 2 adrenoreceptors. The present study was undertaken to determine the direction, time course, and dose-response relationship of detomidine on specific autonomic responses in the unanaesthetized horse. 2. Detomidine was administered intravenously to eight adult thoroughbred racehorses at doses of 0.010-0.040 mg kg-1, according to a double-blind Latin square crossover design. Cardiac and respiratory rates, pupil diameter and rectal temperature were monitored for 180 min postinjection. 3. Detomid...
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...
Camargo FC, Robinson NE, Berney C, Eberhart S, Baker S, DeTolve P, Derksen FJ, Harkins JD, Lehner AF, Tobin T.Trimetoquinol (TMQ) is a potent beta-adrenoceptor agonist bronchodilator used in human medicine but has not been evaluated for potential use as a therapeutic agent for horses with 'heaves'. Objective: To assess the pharmacodynamics of TMQ in horses with 'heaves' to determine potential therapeutic effects. Methods: Increasing doses of TMQ were administered to horses with 'heaves' by i.v. and intratracheal (i.t.) routes. Doses ranged 0.001-0.2 microg/kg bwt i.v. and 0.01-2 microg/kg bwt i.t. Cardiac and airways effects were assessed by measurement of heart rate (HR) and maximal change in pleural...
Errecalde JO, Landoni MF.The pharmacokinetics of a slow-release theophylline formulation was investigated following intravenous and oral administration at 10 mg/kg in horses. A tricompartmental model was selected to describe the intravenous plasma profile. The elimination half-life (t1/2 beta) was 16.91 +/- 0.93 h, the apparent volume of distribution (Vd) was 1.35 +/- 0.18 L/kg and the body clearance (ClB) was 0.061 +/- 0.009 L kg-1 h. After oral administration the half-life of absorption was 1.24 +/- 0.30 h, and the calculated bioavailability was above 100%. The t1/2 beta after oral administration was 18.51 +/- 1.75 ...
Snow DH, Douglas TA.The absorption characteristics of a new paste preparation of phenylbutazone were studied in ponies and thoroughbreds. The results suggested that at a similar dose rate of 5 mg/kg greater bioavailability results from the paste than from a powder preparation. Delivery of an accurate dosage of the paste was not possible using the multidose applicator. Repeated administration of the paste preparation (5 mg/kg twice daily) indicated that it is more toxic to both ponies and thoroughbreds than a powder preparation. In addition to the toxic manifestations previously reported, a neutropenia developed d...
Luna SP, Taylor PM, Brearley JC.Glucose was infused intravenously into six ponies during halothane anaesthesia, to evaluate its effect on their endocrine response to anaesthesia. The ponies were premedicated with acepromazine, and anaesthesia was induced with thiopentone and maintained with halothane in oxygen for two hours. Glucose was infused to maintain the plasma glucose concentration above 20 mmol/litre. Anaesthesia was associated with hypothermia, a decrease in haematocrit, hypotension, hyperoxaemia, respiratory acidosis and an increase in the plasma concentrations of lactate and arginine vasopressin. The concentration...
Baggot JD, Love DN, Rose RJ, Raus R.The serum concentrations of the aminoglycosides neomycin, kanamycin and streptomycin were determined after intravenous (iv) and intramuscular (im) administration. These values were then related to the minimum inhibitory concentrations (MIC) of a number of equine pathogenic bacteria to determine the duration of therapeutic serum concentrations of the aminoglycosides in the horse. Pharmacokinetic analysis of the data using neomycin as the example revealed a mean (+/- sd) peak serum concentration of 23.2 +/- 10.2 micrograms/ml present at 30 mins, and at 8 h the serum concentration was 2.8 +/- 0.8...
Cavalero TMS, Segabinazzi LGTM, Scheeren VFDC, Freitas-Dell'Aqua CP, Papa FO.The present study compared the quality of sperm collected by artificial vagina or pharmacologically induced ejaculation from a 10-year-old thoroughbred stallion with seminal vesiculitis. The pharmacological protocol involved intravenous administration of detomidine (0.01 mg/kg) and oxytocin (20 IU) and successfully induced ejaculation in all attempts of semen collection. Sperm motility, plasma membrane and acrosome integrity (PMAI), reactive oxygen species (ROS) levels, polymorphonuclear neutrophil (PMN) percentage, and bacterial profiles of fresh and cooled semen (5°C for 24 hr) were eval...
Gerken DF, Sams RA.The effects of i.v. chloramphenicol sodium succinate on the pharmacokinetics of i.v. phenylbutazone in six healthy adult horses were investigated. Administration of chloramphenicol sodium succinate to mares reduced mean (+/- SD) phenylbutazone clearance from 0.600 +/- 0.222 to 0.339 +/- 0.123 ml/min per kg and increased mean (+/- SD) half life from 244 +/- 59.8 to 371 +/- 80.8 min and mean residence time from 333 +/- 86.2 to 533 +/- 124 min. The mean steady-state volume of distribution of phenylbutazone was unchanged, with mean (+/- SD) values of 187 +/- 28.9 ml/kg in control animals and 170 +...
Easley JT, Brokken MT, Zubrod CJ, Morton AJ, Garrett KS, Holmes SP.Fourteen horses with septic arthritis underwent high-field (1.5 T) magnetic resonance imaging (MRI). Septic arthritis was diagnosed based on results from historical and clinical findings, synovial fluid analyses and culture, and radiographic, ultrasonographic, arthroscopic, and histopathologic findings. MR findings included diffuse hyperintensity within bone and extracapsular tissue on fat-suppressed images in 14/14 horses (100%), joint effusion, synovial proliferation, and capsular thickening in 13/14 horses (93%), bone sclerosis in 11/14 horses (79%), and evidence of cartilage and subchondra...
Sarasola P, McKellar QA.The effect of an oral dose of probenecid on the disposition kinetics of ampicillin was determined in four horses. An intravenous bolus dose (10 mg/kg) of ampicillin sodium was administered to the horses on two occasions. On the first occasion the antibiotic was administered on its own, and on the second occasion it was administered one hour after an oral dose of 75 mg/kg probenecid. The plasma concentration of probenecid reached a mean (+/- se) maximum concentration (Cmax) of 188-6 +/- 19.3 micrograms/ml after 120.0 +/- 21.2 minutes and concentrations greater than 15 micrograms/ml were present...
Grodzki K.The receptor theory of the action of catecholamines as well as the synthesis and production of beta-adrenolytics gave new perspectives for the treatment of circulatory diseases and enabled to use the beta-adrenergic blockade in electrocardiographic diagnosis. The aim of this work was to study whether it is possible to modify the oral method of administration used in human beings, into intravenous one, and what an information could be obtained as to actual heart condition after practolol injection. The results can be summarized as follows:--Practolol-Polfa injected intravenously in amounts of 3...
White SD, Maxwell LK, Szabo NJ, Hawkins JL, Kollias-Baker C.To determine pharmacokinetics of azathioprine (AZA) and clinical, hematologic, and serologic effects of i.v. and oral administration of AZA in horses. Methods: 6 horses. Methods: In study phase 1, a single dose of AZA was administered i.v. (1.5 mg/kg) or orally (3.0 mg/kg) to 6 horses, with at least 1 week between treatments. Blood samples were collected for AZA and 6-mercaptopurine (6-MP) analysis 1 hour before and at predetermined time points up to 4 hours after AZA administration. In study phase 2, AZA was administered orally (3 mg/kg) every 24 hours for 30 days and then every 48 hours for ...
Cohen ND, Chu KK, Stanley SD, Wang N.To estimate the probability for exceeding a threshold concentration of furosemide commonly used for regulatory purposes after IV administration of furosemide in horses. Methods: 12 mature healthy horses (6 Thoroughbreds and 6 Quarter Horses). 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 administration of 250 or 500 mg of furosemide. Concentrations of furosemide were determined, using an ELISA. Concentration of furosemide was modeled as a function of time, accounting for inter- and intrahorse variabilities. On the basis ...
Brown MP, Kelly RH, Gronwall RR, Stover SM.Six healthy adult mares were given a single IV dose (25 mg/kg of body weight) of chloramphenicol sodium succinate. Chloramphenicol concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The highest measured serum chloramphenicol concentration was 6.21 micrograms/ml at 0.5 hour. Chloramphenicol was detected in synovial and peritoneal fluids, with mean peak concentrations of 3.89 micrograms/ml and 3.50 micrograms/ml, respectively, at 0.5 hour. Serum and synovial concentrations declined rapidly and were not measurable at 3 hours. Chloram...
Salonen JS, Vuorilehto L, Gilbert M, Maylin GA.Horse urine was investigated for metabolites by chromatography and mass spectrometry following the oral administration of the large animal analgesic sedative detomidine to two stallions and intravenous administration of [3H]-detomidine to a mare. Detomidine carboxylic acid and hydroxydetomidine glucuronic acid conjugate were identified in the urine after the oral doses. In addition, traces of free hydroxydetomidine were observed. About half of the radioactivity of [3H]-detomidine was excreted in the urine in 12 h after the i.v. dose (80 micrograms/kg). Most of the excretion occurred between 5 ...
Wilson WD, Spensley MS, Baggot JD, Hietala SK, Pryor P.The pharmacokinetics and bioavailability of ticarcillin and clavulanate were determined after intravenous (i.v.) or intramuscular (i.m.) administration of ticarcillin disodium (50 mg/kg) combined with clavulanate potassium (1.67 mg/kg) to groups of healthy foals at 3 days and 28 days of age. After i.v. administration of the combination to five foals, the disposition kinetics of ticarcillin and clavulanate were best described using a two-compartment open model. Mean plasma elimination-rate constant (beta) and clearance (ClB) for ticarcillin were significantly less (P less than 0.01), and volume...
Hewson J, Johnson R, Arroyo LG, Diaz-Mendez A, Ruiz-López JA, Gu Y, del Castillo JR.Healthy neonatal foals were treated with cefotaxime by bolus (40 mg/kg i.v. q6h for 12 doses; n=10) or by infusion (loading dose of 40 mg/kg i.v. followed by continuous infusion of a total daily dose of 160 mg/kg per 24 h for 3 days; n=5). Population pharmacokinetics was determined, and concentrations in cavity fluids were measured at steady state (72 h). Highest measured serum drug concentration in the bolus group was 88.09 μg/mL and minimum drug concentration (C(min)) was 0.78 μg/mL at 6-h postadministration (immediately before each next dose), whereas infusion resulted in a steady-state c...
Burrows GE, MacAllister CG, Tripp P, Black J.The potential for interactions between chloramphenicol, phenylbutazone, acepromazine and thiamylal and chloramphenicol, rifampin, and phenylbutazone were evaluated in two groups of experiments. In the first, five horses were given thiamylal intravenously (iv) (6.6 mg/kg) after pretreatment with acepromazine, and the time of recumbency was determined. Administration of chloramphenicol iv (25 mg/kg) 1 h prior to anaesthesia significantly lengthened the recumbency time from 21.8 +/- 4.8 mins to 36.0 +/- 8.3 mins. There was an apparent but not statistically significant decrease in recumbency time ...
Aramaki S, Ishidaka O, Suzuki E, Momose A, Umemura K.In a doping test for racing horses, it is useful for the elucidation of the illegal use of drugs if one can estimate the time at which the detected drug was administered. In order to estimate the time which has elapsed after the administration of caffeine (CA) into horses, the ratios of concentration for the respective metabolites to the unchanged CA in the plasma or the urine were determined. These ratios have been known to be independent of the dose of CA. The relationship between [plasma or urinary concentration of a metabolite]/ [plasma or urinary concentration of the unchanged drug] and t...
So YM, Wong JKY, Wong ASY, Tse ATL, Wan TSM, Ho ENM.The erythropoietin mimetic peptide 1 linear form (EMP1-linear), GGTYSCHFGPLTWVCKPQGG-NH , was identified in an unknown preparation consisting of white crystalline powder contained in sealed glass vials using ultrahigh performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). The white crystalline powder, allegedly used for doping racehorses, was found to contain around 2% (w/w) of EMP1-linear. EMP1-linear can be cyclised in equine plasma at physiological temperature of 37°C by forming an intramolecular disulfide bond to give EMP1, which is a well-known erythropoiesis st...
Peck KE, Hines MT, Mealey KL, Mealey RH.To validate use of high-performance liquid chromatography (HPLC) in determining imipramine concentrations in equine serum and to determine pharmacokinetics of imipramine in narcoleptic horses. Methods: 5 horses with adult-onset narcolepsy. Methods: Blood samples were collected before (time 0) and 3, 5, 10, 15, 20, 30, and 45 minutes and 1, 2, 3, 4, 6, 8, 12, and 24 hours after IV administration of imipramine hydrochloride (2 or 4 mg/kg of body weight). Serum was analyzed, using HPLC, to determine imipramine concentration. The serum concentration-versus-time curve for each horse was analyzed se...
Hudson NP, Church DB, Trevena J, Nielsen IL, Major D, Hodgson DR.Two Thoroughbred horses were presented with various clinical signs which included sweating, agitation, muscle twitching and synchronous diaphragmatic flutter. These signs were associated with profound hypocalcaemia. A diagnosis of primary hypoparathyroidism was made on the basis of low serum ionised calcium concentration, hyperphosphataemia and markedly reduced serum immunoreactive parathyroid hormone concentrations in the presence of normal renal function. Treatment with a combination of intravenous calcium and subsequently oral calcium, magnesium and a vitamin D analogue (dihydrotachysterol)...
Martin LM, Bukoski AD, Whelchel DD, Evans TJ, Wiedmeyer CE, Black SJ, Johnson PJ.Pharmacokinetics of lithium chloride (LiCl) administered as a bolus, once i.v. have not been determined in horses. There is no point-of-care test to measure lithium (Li ) concentrations in horses in order to monitor therapeutic levels and avoid toxicity. Objective: To determine the pharmacokinetics of LiCl in healthy adult horses and to compare agreement between two methods of plasma Li concentration measurement: spectrophotometric enzymatic assay (SEA) and inductively coupled plasma mass spectrometry (ICP-MS). Methods: Nonrandomised, single exposure with repeated measures over time. Methods: ...
Rostang A, Desjardins I, Espana B, Panzuti P, Berny P, Prouillac C, Pin D.This study aimed to investigate both the pharmacokinetic behavior and tolerance of methotrexate (MTX) in horses to design a specific dosing regimen as a new immunomodulatory drug for long-term treatment. To determine the primary plasma pharmacokinetic variables after single intravenous, subcutaneous or oral administration, six horses were administered 0.3 mg/kg MTX in a crossover design study. After a 10-week washout, MTX was administered subcutaneously to three of the six previously treated horses at a dose of 0.3 mg/kg once per week for 3 months. In both studies, MTX and metabolite concen...
Solano M, Welcome J, Johnson K.Horses undergoing skeletal scintigraphy can have decreased radiopharmaceutical bone uptake in the limbs. This reduces the diagnostic value of the scan. The aim of the present study was to measure the changes in count density caused by vasodilatation and increased blood flow associated with intravenous injection of acepromazine during bone scintigraphy in normal horses. A three-phase bone scan was performed twice in 11 adult horses to study the effects of acepromazine on the count density of the resultant scintigrams. With acepromazine, there was a statistically significant mean difference of 1...
Gulick BA, Meagher DM.A commercially available polyvinyl chloride intravenous catheter was studied in 9 horses for 3 to 10 days to evaluate the catheter's suitability for use in the horse, to develop a new insertion technique, and to establish a protocol for catheter care. Seven of the animals were clinically normal horses receiving parenteral nutrition; one was a horse with hypocalcemia receiving frequent intravenous injections of calcium gluconate, and one was a clinically normal horse receiving no infusions. The catheter dressings were changed every 48 hours, and an aspirate from the catheter and the catheter ti...
