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.
Stadler P, van Amstel SR.The results of a study conducted to determine the clinico-pathological changes in 4 experimentally-induced cases of endotoxaemia in the horse are reported on. Endotoxaemia was induced by injecting commercially available E. coli 055:B5 lipopolysaccharide intravenously at a dose of 1 microgram kg-1. The haematocrit, red cell count, total and differential white cell counts, thrombocyte count, prothrombin time, partial thromboplastin time, fibrinogen level, level of fibrin degradation products, arterial acid-base status, serum lactate and blood glucose were determined repeatedly. Changes that occu...
Bello TR.Antiparasitic efficacy of ivermectin against migrating Gasterophilus intestinalis was evaluated in 36 treated and 24 nontreated (n = 12) or vehicle-treated (n = 12) ponies experimentally and naturally infected with G intestinalis and naturally infected with G nasalis. Each pony was experimentally infected with 500 G intestinalis 1st instars in 2 divided doses on days -14 and -7 before treatment. On day 0, ivermectin was administered at the rate of 200 micrograms/kg of body weight by IV (n = 12) or IM injection (n = 12) or given as an oral paste (n = 12). Ponies were euthanatized and necropsied...
Hildebrand SV, Hill T.Atracurium (0.4 mg/ml in isotonic NaCl solution) was administered by IV infusion to 7 healthy adult horses for 2 hours. Over the 2-hour period, a 95 to 99% reduction of train-of-four hoof-twitch response was maintained by 0.17 +/- 0.01 mg of atracurium/kg of body weight/h, for a total of 161 +/- 6 mg of atracurium (mean +/- SEM) for horses 1 to 4, 6, and 7. Horse 5, a mare in estrus, required 0.49 mg of atracurium/kg/h to maintain comparable relaxation. Hoof-twitch recovery time from 10 to 75% of baseline strength was 19.8 +/- 2.5 minutes for all horses. The 10 to 75% recovery time for horse 5...
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...
Grandy JL, Hodgson DS, Dunlop CI, Chapman PL, Heath RB.The cardiopulmonary effects of intravenous (i.v.) administration of the sympathomimetic drug ephedrine during two different levels of halothane anesthesia [end-tidal concentration of 1.37% (light anesthesia) and 2.1% (deep anesthesia)] were studied in eight horses. Anesthesia was induced and maintained using only halothane in O2. Ventilation was controlled to maintain a Paco2 of 38-42 mmHg. Following instrumentation and stabilization of the horse at the halothane concentration being studied, baseline measurements of cardiac output (Q), arterial blood pressure (AP), pulmonary artery pressure, h...
Boyd EH, Allen WE.Plasma drug concentrations were measured after two commercially available potentiated sulphonamides, trimethoprim and sulfadoxine and trimethoprim and sulphadiazine, were infused daily for 2 and 3 days, respectively, into the uteri of pony mares which had been mated before ovulation. Intravenous administration of trimethoprim and sulfadoxine allowed uterine absorption of trimethoprim (23-43%) and sulfadoxine (29-34%) to be calculated. After intra-uterine administration trimethoprim and sulphadiazine were detected in the milk of a lactating mare. In order to maintain plasma concentrations likel...
Clark ES, Moore JN.Lateral cecal arterial blood flow, carotid arterial pressure, heart rate, and mechanical activity in the duodenum, right ventral colon, cecal body, and cecal apex were measured in 6 conscious healthy horses for 60 minutes during and for 120 minutes after IV infusion of 0.9% NaCl solution (control) or fenoldopam. There were no significant changes in these measurements during or after infusion of 0.9% NaCl (saline) solution. Fenoldopam, a selective dopamine-1 receptor agonist, was administered in saline solution at dosages of 0.01, 0.05, and 0.1 micrograms/kg/min. Intravenous infusion of fenoldo...
Juzwiak JS, Brown MP, Gronwall R, Houston AE.Cephapirin (20 mg/kg of body weight, IV) was administered before and after 3 doses of probenecid (25, 50, or 75 mg/kg, intragastrically, at 12-hour intervals) to 2 mares. Clearance and apparent volume of distribution, based on area under the curve, were negatively correlated with probenecid dose. Clearance of cephapirin was decreased by approximately 50% by administration of 50 mg of probenecid/kg. Serum, synovial fluid, peritoneal fluid, CSF, urinary, and endometrial concentrations of cephapirin were determined after 5 doses of cephapirin (20 mg/kg, IM, at 12-hour intervals) without and with ...
Stadler P, Van Amstel SR.Commercially available Escherichia coli 055: B5 lipopolysaccharide was administered intravenously experimentally at a dosage of 10 micrograms/kg to 2 horses. Various clinical and clinico-pathological parameters were monitored before and after the endotoxin administration. Because of a hopeless prognosis, and for humane reasons, euthanasia was applied on both horses 6 h after administration. Values recorded for the different parameters, including the blood lactate level, were consistent with a lethal condition. It would appear that an intravenous dose of 10 micrograms/kg of endotoxin is potenti...
Byars TD, Simpson JS, Divers TJ, Shiner KA, Rantanen NW.Percutaneous nephrostomy was used to provide urine output in a 3-year-old Thoroughbred filly with azotemia and obstructive ureterolithiasis. Previous left ureteral surgery had failed to provide clinical improvement, and the filly became more azotemic. Nephrostomy was performed in the standing patient, with ultrasonographic guidance and local anesthesia. Continuing IV fluid therapy and diuresis through the nephrostomy tube resulted in a decrease in clinical signs of azotemia. However, the filly developed a cecal impaction, which ruptured during surgery because of colic, and was euthanatized.
Young DR, Divers TJ, Benson CE.Clinical septicemia developed in 2 clinically normal horses after both were administered a portion of an amino acid solution IV. Serratia marcescens was subsequently isolated from blood of both horses. The isolates were shown to be identical on the basis of antibiograms and plasmid biochemistry, incriminating the infusate as the source of bacterial infection. The horses recovered after supportive and antimicrobial treatment.
Spier SJ, Meagher DM.Rational perioperative management improves the success rate of abdominal surgery. Important aspects of management are discussed, including principles of fluid therapy, nutrition, intravenous catheterization, antimicrobial prophylaxis, and the use of nonsteroidal anti-inflammatory medication. Current advances in the area of immunotherapy are mentioned.
Clark ES, Moore JN.Lateral cecal arterial blood flow, carotid arterial pressure, heart rate, and mechanical activity of the circular and longitudinal muscle layers of the cecal body were measured in 7 conscious healthy horses during IV infusion of physiologic saline solution for 60 minutes (control), during a 60-minute IV infusion of dopamine (at dosages of 1, 2.5, and 5 micrograms/kg/min), and for 60 minutes after IV infusion of dopamine. The mean values for lateral cecal arterial blood flow during IV infusion of dopamine at a dosage of either 1 or 2.5 micrograms/kg/min were not significantly different from the...
Clark ES, Moore JN.The effects of slow intravenous (i.v.) infusion of a very low dosage of endotoxin (a cumulative dosage of 0.03 microgram/kg bodyweight [bwt] infused over 60 mins) were evaluated in six conscious healthy horses. Duodenal, right ventral colon, and caecal contractions were detected with strain gauge force transducers. Lateral caecal arterial blood flow was measured using transit time ultrasonic blood flow probes. Duodenal contractile activity was not significantly altered by infusion of endotoxin. In contrast, the contractile activity of the right ventral colon 90 and 270 mins after infusion of e...
Tillman LG, Moore JN.The activity of serum angiotensin converting enzyme (ACE) for healthy horses was 64 +/- 13 mUnits/ml. In vitro, equine serum ACE was sensitive to the following inhibitors (IC50): enalapril (570 nM or 215 ng/ml), captopril (190 nM or 41.3 ng/ml), and enalaprilat (6 nM or 2.1 ng/ml). The intravenous (i.v.) administration of angiotensin I to six healthy horses produced a dose proportional pressor response. The maximal increase in mean arterial pressure over baseline values was 65.6 mmHg at angiotensin I doses of 500 ng/kg bodyweight (bwt). The attenuation of this response to angiotensin I was fur...
Jochle W, Moore JN, Brown J, Baker GJ, Lowe JE, Fubini S, Reeves MJ, Watkins JP, White NA.Detomidine hydrochloride, butorphanol tartrate, flunixin meglumine and xylazine hydrochloride were evaluated in a blind multi-centre clinical trial in 152 horses with abdominal pain. The drugs were administered as follows: detomidine 20 or 40 micrograms/kg bodyweight (bwt); butorphanol 0.1 mg/kg bwt; flunixin meglumine 1.0 mg/kg bwt; xylazine hydrochloride 0.5 mg/kg bwt. Each centre compared responses to the two doses of detomidine with those to one of the other analgesics. The drugs were administered intravenously (i.v.) after clinical assessment of the degree of sweating, kicking, pawing, he...
Trim CM, Moore JN, Clark ES.An ultrasonic flow probe was implanted around a branch of the left renal artery in five horses. The effects of dopamine were studied in the unsedated horses 10 days after surgery. Three experiments, separated by at least two days, were performed in random order on each horse. In two experiments, dopamine was infused intravenously for 60 mins at either 2.5 and 5.0 micrograms/kg bodyweight (bwt)/min. Saline was infused for 60 mins before and after each infusion, and for 180 mins in the third experiment as a control. Renal blood flow increased during administration of dopamine at both dose rates ...
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...
King JN, Gerring EL.Post operative ileus is a serious complication of abdominal surgery in horses and there is evidence that endotoxin plays a significant role in its pathogenesis. Pre-treatment with intravenous (i.v.) flunixin (1.1 mg/kg bodyweight [bwt]) or phenylbutazone (4.4 mg/kg bwt) significantly antagonised the acute disruption of gastric, small intestinal and large intestinal motility induced by 0.1 microgram/kg bwt i.v. endotoxin in ponies implanted with gastrointestinal strain gauges. Phenylbutazone was more effective than flunixin and this was significant (P < 0.01) for the stomach and left dorsal col...
Hubbell JA, Bednarski RM, Muir WW.The cardiopulmonary and anesthetic effects of xylazine in combination with a 1:1 mixture of tiletamine and zolazepam were determined in 6 horses. Each horse was given xylazine IV or IM, as well as tiletamine-zolazepam IV on 4 randomized occasions. Anesthetics were administered at the rate of 1.1 mg of xylazine/kg of body weight, IV, 1.1 mg of tiletamine-zolazepam/kg, IV (treatment 1); 1.1 mg of xylazine/kg, IV, 1.65 mg of tiletamine-zolazepam/kg, IV (treatment 2); 1.1 mg of xylazine/kg, IV, 2.2 mg of tiletamine-zolazepam/kg, IV (treatment 3); and 2.2 mg of xylazine/kg, IM, 1.65 mg of tiletamin...
Zaugg JL, Lane VM.We evaluated the efficacy of buparvaquone in eliminating Babesia equi of European origin in carrier horses and in experimentally infected splenectomized ponies. When administered at the rate of 2.5 mg/kg of body weight, IM, 4 times at 96-hour intervals, buparvaquone was effective in eliminating B equi carrier infection in 1 horse. Such results could not be repeated at the same dosage or at 3.5 or 5 mg/kg, IM. Buparvaquone given at the rate of 4 to 6 mg/kg IV and/or IM was therapeutically effective in 4 of 5 acute B equi infections in splenectomized ponies. The treated ponies became carriers.
Prades M, Brown MP, Gronwall R, Houston AE.After single oral administration of ketoconazole (30 mg/kg bodyweight [bwt]) in 50 ml of corn syrup to a healthy mare, the drug was not detected in serum. Ketoconazole in 0.2 N HC1 was administered intragastrically to six healthy adult horses in five consecutive doses of 30 mg/kg bwt at 12 h intervals. Ketoconazole concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid (CSF), urine and endometrium. Mean peak serum ketoconazole concentration was 3.76 micrograms/ml at 1.5 to 2 h after intragastric administration. Mean peak synovial concentration was 0.87 mic...
Carrick JB, Papich MG, Middleton DM, Naylor JM, Townsend HG.The effects of daily intravenous administration of flunixin meglumine at dosages of 0.55, 1.1, 2.2 and 6.6 mg/kg for five days were examined in neonatal foals. Six two day old foals were used to evaluate the effect of each dosage. Foals were examined every day and blood samples collected on days 1, 3 and 6. All foals were euthanized after six days, necropsied and examined for lesions. The major clinical abnormality was diarrhea, but the incidence was not related to the dosage of flunixin meglumine administered. The foals receiving 6.6 mg/kg of flunixin meglumine had significantly more gastroin...
Beadle RE, Short CR, Corstvet RE, Pawlusiow J, Nobles DD, McClure JR, Guthrie AJ, Clarke CR.A soft-tissue infection model was created in eight horses by infecting subcutaneous tissue chambers with Streptococcus zooepidemicus organisms. Responses of the horses to the infections were determined by monitoring changes in the complete blood count and body temperature and by following changes in the cytology and protein content of the tissue chambers. Systemic reactions to the infections included a mild neutrophilia, mild pyrexia and mild anemia. There was a marked influx of neutrophils and protein into the chambers after they were seeded with bacteria and chamber neutrophil viability decr...
Salonen JS, Vähä-Vahe T, Vainio O, Vakkuri O.The pharmacokinetics of detomidine, a novel analgesic sedative, was studied in the major target species after high (80 micrograms/kg) i.v. and i.m. doses. In addition, drug residues in some organs were determined. Concentrations were measured using a sensitive, detomidine-specific radio-immunoassay method. Rapid absorption following i.m. dosing occurred. Absorption half-lives were 0.15 h (horse) and 0.08 h (cattle). The mean peak concentration in the horse (51.3 ng/ml) was achieved in 0.5 h and in the cow (65.8 ng/ml) in 0.26 h. The areas under the concentration curve after i.m. dosing were 66...
Zwain I, Gaillard JL, Dintinger T, Silberzahn P.A single i.m. injection of testosterone (750 mg of testosterone bexahydrobenzoate) or i.v. injection of human chorionic gonadotrophin (hCG) (10,000 IU) was given to geldings and stallions. Levels of unconjugated and conjugated (after solvolysis) androgens and estrogens were measured in blood and urine samples taken daily from the day of injection (D0) to the tenth day post-injection (D10). In the stallion, both treatments resulted in a sharp increase of plasma estrogens, which peaked one day before the androgen levels. Our results confirmed the testicular localization of a potent aromatase, wh...
Delbeke FT, Debackere M.The prototype of a commercial ELISA test kit designed for fentanyl determination in human urine has been evaluated for screening fentanyl in horse urine and plasma. The measurement of fentanyl after intravenous (2 mg) and intramuscular (0.25 mg) administration in undiluted plasma was not reproducible while accurate quantification of fentanyl in urine greatly depends on the composition of the horse urine. The ELISA assay, however, is simple and could be successfully used for quantitative measurements in diluted urine and for rapid qualitative screening for fentanyl in large numbers of urine sam...
Darien BJ, Potempa J, Moore JN, Travis J.Two synthetic substrate assays (fluorometric and chromogenic) were used to measure antithrombin-III (AT-III) activity (residual thrombin activity) in non-medicated and heparin (sodium) treated horses. In 18 non-medicated horses the fluorometric substrate assay (FSA) values were similar to previous reports but they reflected inconsistent trends and larger deviations in the heparin-treated groups (Group 2: 40 and 100 U/kg IV, n = 6; Group 3: 240 U/kg IV, n = 5; Group 4: 80 U/kg IV followed by 160 U/kg SC, n = 8) when compared to the chromogenic substrate assay (CSA) values. The CSA values for th...
Brown MP, Gronwall RR, Houston AE.Six healthy adult mares were each given an oral loading dose of ormetoprim(OMP)-sulfadimethoxine (SDM) at a dosage of 9.2 mg of OMP/kg and 45.8 mg of SDM/kg, followed by four maintenance doses of 4.6 mg of OMP/kg and 22.9 mg of SDM/kg, at 24 h intervals. Ormetoprim and SDM concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid, urine and endometrium. The highest mean serum OMP concentration was 0.92 micrograms/mL 0.5 h after the first dose; the highest mean SDM concentration was 80.9 micrograms/mL 8 h after the first dose. The highest mean synovial fluid c...
Darien BJ, Potempa J, Moore JN, Travis J.Two synthetic substrate assays (fluorometric and chromogenic) were used to measure antithrombin-III (AT-III) activity (residual thrombin activity) in non-medicated and heparin (sodium) treated horses. In 18 non-medicated horses the fluorometric substrate assay (FSA) values were similar to previous reports but they reflected inconsistent trends and larger deviations in the heparin-treated groups (Group 2: 40 and 100 U/kg IV, n = 6; Group 3: 240 U/kg IV, n = 5; Group 4: 80 U/kg IV followed by 160 U/kg SC, n = 8) when compared to the chromogenic substrate assay (CSA) values. The CSA values for th...
Giraudet A, Hinchcliff KW, Kohn CW, McKeever KH.Plasma insulin concentration of many species has a characteristic early or acute-phase response in the minutes after IV administration of glucose. However, the plasma insulin response of horses soon after the IV administration of glucose has not been examined, whereas the more prolonged response has been evaluated. We examined the plasma insulin and glucose concentration responses of adult mares during the 30 minutes after rapid IV administration of glucose (0.33 g/kg of body weight). Plasma glucose concentration peaked at 664 +/- 54 mg/dl within 1 minute of cessation of glucose administration...
Goetz TE, Manohar M.The effect of age on maximal heart rate induced by IV infusion of isoproterenol was studied in 19 healthy, sedentary, normothermic horses ranging in age from 0.25 to 9.90 years. Isoproterenol was administered IV (1.0 micrograms/kg of body weight/min) for 3 minutes, and the heart rate attained during the last 30 seconds of the infusion was determined. Linear regression of the maximal heart rate on age suggested that the rate decreased with age in a trend described by the equation: maximal heart rate (beats/min) = 209.63 - 3.28 x age (years). The regression coefficient (r) for this relation was ...
Moser LR, Lawrence LM, Novakofski J, Powell DM.1. Clearance of infused lipid was observed in six mature resting horses, 2 to 6 hr after receiving a meal of alfalfa hay. 2. Intralipid, a 10% triglyceride emulsion, was infused at a rate of 0.2 ml/kg into the jugular vein. 3. Blood samples were obtained for 80 min post-infusion and assayed for plasma triglyceride concentration. 4. Clearance rate of the infused lipid was very slow (mean t1/2 = 269 min). 5. The clearance rate of the infused lipid in these horses was much slower than has been observed in other species. 6. The slow clearance of infused triglyceride in horses may suggest an inabil...
Keegan RD, Gleed RD, Sanders EA, Seaman GC, Wertz EM, Short CE.Clenbuterol (0.8 microgram/kg intravenously) was administered to 10 anesthetized horses with an abnormally low PaO2 (less than 90 mm Hg) despite controlled ventilation with an oxygen-rich gas mixture. Results were compared with those from 10 controls to which no clenbuterol was given and in which conventional methods to increase PaO2 were ongoing. Horses treated with clenbuterol had higher PaO2 values for at least 90 minutes. Clenbuterol was associated with increased heart rate and profuse sweating. Clenbuterol can be administered intravenously to increase the PaO2 of mechanically ventilated h...
Gardner SY, Sweeney RW, Divers TJ.Serum concentrations of cefotaxime and desacetylcefotaxime were measured in 1-week-old pony foals after IV administration of a single dose of cefotaxime. The cefotaxime disposition data conformed to a two-compartment model with elimination half-life of 0.60 hour. The combined cefotaxime and desacetylcefotaxime data was best described by a four-compartment model. The apparent half-life describing the disappearance of desacetylcefotaxime was 1.69 hours. Dosage of 40 mg/kg of body weight given IV every 4 to 6 hours for neonatal foals with gram-negative septicemia and every 2 hours for foals with ...
Goetz TE, Manohar M.The heart rate (HR) induced by maximal beta-adrenergic activation, which was elicited by infusion of isoproterenol, was studied in 8 healthy horses before (control) and after hyperthermia was induced by IV administration of 2,4-dinitrophenol (DNP). Isoproterenol was administered IV at 1.0 micrograms.kg-1.min-1 for 3 minutes, and the HR was determined during the final 30 seconds of the infusion. As the rectal temperature increased (P less than 0.001) from 38.2 +/- 0.1 C (mean +/- SEM; normothermic control) to 40.1 +/- 0.1 C at 60 minutes after DNP administration, the isoproterenol-induced HR al...
Lees P, Maitho TE, Taylor JB.A clinical dose rate (4.4 mg/kg bodyweight) of phenylbutazone was administered intravenously and orally to six Welsh mountain ponies to provide data on the pharmacokinetics and bioavailability of the drug. In three, three-year-old ponies, clearance of the drug from plasma after intravenous administration was almost twice as rapid as in three ponies aged eight to 10 years. After oral administration, plasma phenylbutazone levels were greater in the older ponies, the area under the plasma concentration time curve being almost twice as high. This did not result from more efficient absorption but f...
Sweeney CR, Soma LR, Beech J, Reef V, Simmons R.Serum and peritoneal fluid concentrations of ticarcillin were measured in 10 healthy adult horses from 0.5 to 8 hours after IV or IM administration of 44 mg/kg of body weight. After IV injection, the serum concentration at 30 minutes was 104.3 +/- 6.1 mg/L and the mean peak peritoneal fluid concentration (61.4 +/- 29.0 mg/L) occurred 2 hours after injection. The peak serum (28.3 +/- 5.5 mg/L) and the peak peritoneal fluid concentrations (19.2 +/- 6.0 mg/L) occurred 2 hours after the IM injection. Ticarcillin (greater than or equal to 2 mg/L) persisted in serum and peritoneal fluid for 6 hours ...
Osz E, Réthy L.The authors have compared the anaphylaxis due to active and passive sensitization of mice. In the case of active sensitizing, anti-mouse anti-thymocyte horse serum (ATS), and/or normal horse serum (NHS), whereas in the case of passive sensitizing, plasma, peripheral leukocytes, spleen cells and thymocytes of sensitized animals were used. Provocation of shock was carried out by intravenous administration of ATS or NHS. Irreversible anaphylaxis occurred in a significantly higher rate in the case of ATS than NHS sensitivity, produced either actively, or passively. Differences have been found also...
Boles C.Adequate post-operative management of equine abdominal patients is as necessary to patient survival as the most heroic corrective surgery. Post-operative management must begin during the anaesthesia recovery phase to insure adequate oxygen supply, ventilation, and minimize any abdominal discomfort. The animal's physiological status must be constantly monitored to detect and determine the degree of abnormalities concerning serum electrolytes, fluid balance, and acid-base abnormalities. The most commonly observed serum electrolyte imbalance is hypokalaemia. Replacement potassium is usually suppl...
Frey HH, Fitzek A, Wintzer HJ, Baumgärtel E.Use of the potent, high-ceiling diuretic bumetanide made it possible to obtain urinary samples for dope testing of trotters within the 1st hour after the race. The drug was injected intravenously at a dose level of 10 mug/kg during the cold season of the year, but on warm days, a dose of 20 mug/kg was more reliable. These doses did not produce any side-effects and did not interfere with the detection of doping drugs, since bumetanide is not metabolized to a detectable degree and the unchanged drug appears only in extracts from acidic urine. By enhancing the clearance of drugs used for doping, ...
Dyer DC, Hsu WH, Lloyd WE.Twenty healthy ponies were given i.v. 1.1 mg/kg of xylazine from 2 manufacturers and the pharmacokinetic parameters calculated from the disposition curves. The disposition curves for the 2 commercial preparations were not different. Yohimbine, an antagonist of the pharmacologic effects produced by xylazine, did not alter the disposition of xylazine in the plasma. A single i.v. bolus of xylazine was completely described in 17 of 20 animals by the biexponential equation: Cp = 1.30e(-0.3955t) + 0.58e(-0.033t) where Cp represents the concentration of xylazine in the plasma at time t (min). The t1/...
Friedrich A, Hagedorn HW, Schulz R.Due to their marked antiinflammatory effect, synthetic corticosteroids are used to mask illness, especially lameness in horses. The detection of these drugs in equine body fluids requires accurate methods, particularly where misuse of corticosteroids is suspected. Gas chromatography/mass spectrometry (GC/MS) is well established as a reliable technique for the identification of drugs in biological fluids. Using GC/MS, we determined dexamethasone levels in horse urine and serum after intravenous application of a therapeutic dose. Dexamethasone was detectable, in serum for up to six hours, and in...
Stadler P, Van Amstel SR.Commercially available Escherichia coli 055: B5 lipopolysaccharide was administered intravenously experimentally at a dosage of 10 micrograms/kg to 2 horses. Various clinical and clinico-pathological parameters were monitored before and after the endotoxin administration. Because of a hopeless prognosis, and for humane reasons, euthanasia was applied on both horses 6 h after administration. Values recorded for the different parameters, including the blood lactate level, were consistent with a lethal condition. It would appear that an intravenous dose of 10 micrograms/kg of endotoxin is potenti...
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...
Cohen ND, Hu Z, Stanley SD, Wang N.Furosemide is frequently used to control or prevent exercise-induced pulmonary hemorrhage in performance horses. The bronchodilating agent clenbuterol is also commonly used as a treatment for inflammatory airway disease in performance horses. Use of both medications is regulated by many racing authorities. The effects of concomitant administration of furosemide and clenbuterol on the pharmacokinetics of clenbuterol have not been well characterized. A study was designed to evaluate the influence of furosemide on serum and urine concentrations of clenbuterol after oral administration of clenbute...