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.
Fernández-Varón E, Cárceles CM, Marín P, Martos N, Escudero E, Ayala I.To study the pharmacokinetics of difloxacin (5 mg/kg) following IV, IM, and intragastric (IG) administration to healthy horses. Methods: 6 healthy mature horses. Methods: A crossover study design with 3 phases was used (15-day washout periods between treatments). An injectable formulation of difloxacin (5%) was administered IV and IM in single doses (5 mg/kg); for IG administration, an oral solution was prepared and administered via nasogastric tube. Blood samples were collected before and at intervals after each administration. A high-performance liquid chromatography assay with fluorescence ...
Sinclair MD, Mealey KL, Matthews NS, Peck KE, Taylor TS, Bennett BS.To determine the disposition of a bolus of meloxicam (administered IV) in horses and donkeys (Equus asinus) and compare the relative pharmacokinetic variables between the species. Methods: 5 clinically normal horses and 5 clinically normal donkeys. Methods: Blood samples were collected before and after IV administration of a bolus of meloxicam (0.6 mg/kg). Serum meloxicam concentrations were determined in triplicate via high-performance liquid chromatography. The serum concentration-time curve for each horse and donkey was analyzed separately to estimate standard noncompartmental pharmacokinet...
Davis JL, Salmon JH, Papich MG.To characterize pharmacokinetics of voriconazole in horses after oral and IV administration and determine the in vitro physicochemical characteristics of the drug that may affect oral absorption and tissue distribution. Methods: 6 adult horses. Methods: Horses were administered voriconazole (1 mg/kg, IV, or 4 mg/kg, PO), and plasma concentrations were measured by use of high-performance liquid chromatography. In vitro plasma protein binding and the octanol:water partition coefficient were also assessed. Results: Voriconazole was adequately absorbed after oral administration in horses, with a s...
Bentz BG, Maxwell LK, Erkert RS, Royer CM, Davis MS, MacAllister CG, Clarke CR.The purpose of the study reported here was to describe the bioavailability and pharmacokinetics of acyclovir after intravenous and oral administration to horses. Six healthy adult horses were used in a randomized cross-over study with a 3 x 3 Latin square design. Three treatments were administered to each horse: 10 mg of injectable acyclovir/kg of body weight in 1 L of normal saline delivered as an infusion over 15 minutes; 10 mg of acyclovir/kg in tablets by nasogastric intubation; and 20 mg of acyclovir/kg in tablets by nasogastric intubation. A 2-week washout period was provided between eac...
Thomasy SM, Steffey EP, Mama KR, Solano A, Stanley SD.Fentanyl decreases the minimum alveolar concentration (MAC) of inhaled anaesthetics and has been used clinically to reduce the requirements of other anaesthetic drugs in humans and small animals. We hypothesized that i.v. fentanyl would decrease the MAC of isoflurane in horses in a dose-dependent manner. Methods: Following determination of baseline MAC of isoflurane, fentanyl was administered i.v. to target plasma concentrations of 1, 8 and 16 ng ml(-1). Each horse was randomly assigned two of three target concentrations administered in ascending order. Loading and infusion doses for each hors...
Hubbell JA, Muir WW.The ability to shorten the duration of sedation would potentially improve safety and utility of detomidine. Objective: To determine the effects of tolazoline and atipamezole after detomidine sedation. Objective: Administration of tolazoline or atipamezole would not affect detomidine sedation. Methods: In a randomised, placebo-controlled, double-blind, descriptive study, detomidine (0.02 mg/kg bwt i.v.) was administered to 6 mature horses on 4 separate occasions. Twenty-five mins later, each horse received one of 4 treatments: Group 1 saline (0.9% i.v.) as a placebo control; Group 2 atipamezole...
Davis JL, Papich MG, Weingarten A.The purpose of this study was to determine the pharmacokinetics and physicochemical characteristics of orbifloxacin in the horse. Six healthy adult horses were administered oral and intravenous orbifloxacin at a dose of 2.5 mg/kg. Plasma samples were collected and analyzed by high-pressure liquid chromatography with ultraviolet detection. Plasma protein binding and lipophilicity were determined in vitro. Following i.v. administration, orbifloxacin had a terminal half-life (t1/2) of 5.08 h and a volume of distribution (V(d(SS))) of 1.58 L/kg. Following oral administration, the average maximum p...
Schwarzwald CC, Sams RA, Bonagura JD.The pharmacokinetics of diltiazem were determined in eight healthy horses. Diltiazem HCl, 1 mg/kg i.v., was administered over 5 min. Venous blood samples were collected at regular intervals after administration. Plasma concentrations of diltiazem and desacetyldiltiazem were determined by high-performance liquid chromatography. A second, putative metabolite was detected, but could not be identified due to the lack of an authentic standard. Data were analyzed by nonlinear least-squares regression analysis. The median (minimum-maximum) peak plasma concentration of diltiazem was 727 (539-976) ng/m...
Love EJ, Lane JG, Murison PJ.To determine the effect of morphine administration on commonly monitored cardio-respiratory variables and recovery quality in horses undergoing anaesthesia and surgery. Methods: Prospective, randomized clinical study. Methods: Thirty-eight thoroughbred horses, 32 geldings and six mares, 3-13 years old, weighing 411-600 kg. Methods: A standard anaesthetic technique was used. Twenty minutes after induction of anaesthesia horses received 0.1 mg kg(-1) (0.1 m) or 0.2 mg kg(-1) (0.2 m) morphine by intravenous injection. A control group did not receive morphine. Heart rate, respiratory rate (fr), me...
Borer KE, Clarke KW.To determine whether hyoscine has a sparing effect on the volume of dobutamine required to maintain mean arterial pressure (MAP) at 70 mmHg in horses anaesthetized with halothane. Methods: Prospective, randomized, controlled clinical trial. Methods: Twenty adult horses weighing 507 +/- 97 kg (mean +/- SD), aged 10 +/- 5 years. Methods: Pre-anaesthetic medication in all horses was intramuscular (IM) acepromazine (40 mug kg(-1)) and intravenous (IV) detomidine (0.02 mg kg(-1)). Anaesthesia was induced with ketamine (2.2 mg kg(-1) IV) and diazepam (0.02 mg kg(-1) IV), and maintained with halothan...
Laan TT, Bull S, Pirie RS, Fink-Gremmels J.Cyclic AMP elevating agents have been shown to exhibit anti-inflammatory properties in addition to functions such as bronchodilation. The aim of this study was to investigate this dual action of clenbuterol (CB; Ventipulmin) on horses affected with recurrent airway obstruction (RAO). Seven RAO susceptible horses received inhalation challenges with aerosolised lipopolysaccharide (LPS), hay dust suspension (HDS) and Aspergillus fumigatus antigen (AF) with and without prior treatment with intravenous CB. Data showed that CB exerted significant beneficial effects on lung function, total cell count...
Umar MA, Yamashita K, Kushiro T, Muir WW.Objective-To compare the anesthetic and cardiorespiratory effects of total IV anesthesia with propofol (P-TIVA) or a ketamine-medetomidine-propofol combination (KMP-TIVA) in horses. Design-Randomized experimental trial. Animals-12 horses. Procedure-Horses received medetomidine (0.005 mg/kg [0.002 mg/lb], IV). Anesthesia was induced with midazolam (0.04 mg/kg [0.018 mg/lb], IV) and ketamine (2.5 mg/kg [1.14 mg/lb], IV). All horses received a loading dose of propofol (0.5 mg/kg [0.23 mg/lb], IV), and 6 horses underwent P-TIVA (propofol infusion). Six horses underwent KMP-TIVA (ketamine [1 mg/kg/...
Morresey PR, Mackay RJ.To measure serum polymyxin B concentration after single and repeated IV infusions in horses. Methods: 5 healthy horses. Methods: In study 1, 1 mg (6,000 U) of polymyxin B/kg was given IV and blood samples were collected for 24 hours. In study 2, 1 mg of polymyxin B/kg was given IV every 8 hours for 5 treatments and blood samples were collected until 24 hours after the last dose. Polymyxin B concentration was measured as the ability to suppress nitrite production by murine macrophages stimulated with lipopolysaccharide and interferon-alpha. Urine was collected prior to the first drug infusion a...
Olsén L, Ingvast-Larsson C, Larsson P, Broström H, Bondesson U, Sundqvist M, Tjälve H.The pharmacokinetics and the effects on inhibition of histamine-induced cutaneous wheal formation of the histamine H1-antagonist fexofenadine were studied in horse. The effect of ivermectin pretreatment on the pharmacokinetics of fexofenadine was also examined. After intravenous infusion of fexofenadine at 0.7 mg/kg bw the mean terminal half-life was 2.4 h (range: 2.0-2.7 h), the apparent volume of distribution 0.8 L/kg (0.5-0.9 L/kg), and the total body clearance 0.8 L/h/kg (0.6-1.2 L/h/kg). After oral administration of fexofenadine at 10 mg/kg bw bioavailability was 2.6% (1.9-2.9%). Ivermect...
De Clercq D, Baert K, Croubels S, van Loon G, Maes A, Tavernier R, Deprez P, De Backer P.To determine the clinical effects and pharmacokinetics of amiodarone after single doses of 5 mg/kg administered orally or intravenously. Methods: 6 healthy adult horses. Methods: In a cross over study, clinical signs and electrocardiographic variables were monitored and plasma and urine samples were collected. A liquid chromatography-mass spectrometry method was used to determine the percentage of protein binding and to measure plasma and urine concentrations of amiodarone and the active metabolite desethylamiodarone. Results: No adverse clinical signs were observed. After IV administration, m...
Lescun TB, Ward MP, Adams SB.To compare gentamicin concentrations achieved in synovial fluid and joint tissues during IV administration and continuous intra-articular (IA) infusion of the tarsocrural joint in horses. Methods: 18 horses with clinically normal tarsocrural joints. Methods: Horses were assigned to 3 groups (6 horses/group) and administered gentamicin (6.6 mg/kg, IV, q 24 h for 4 days; group 1), a continuous IA infusion of gentamicin into the tarsocrural joint (50 mg/h for 73 hours; group 2), or both treatments (group 3). Serum, synovial fluid, and joint tissue samples were collected for measurement of gentami...
Garcia Lascurain AA, Sumano Lopez H, Steffey EP, Santillán Doherty P, Hernandez EN.To characterize behavioral and physiological responses to short-term, unsupplemented intravenous (IV) anesthesia in healthy horses at high altitude (2240 m), and to test the hypothesis that the dose of butorphanol modifies the response of the horse to propofol anesthesia following xylazine pre-medication. Methods: Randomized prospective butorphanol dose cross-over experimental design. Animals Eight healthy horses, 13 +/- 6 (mean +/- SD) years of age, and weighing 523 +/- 26 kg. Methods: Each horse was anesthetized three times with at least 3 weeks between each anesthesia. After collecting pre-...
Feary DJ, Mama KR, Thomasy SM, Wagner AE, Enns RM.To determine the disposition of lidocaine after IV infusion in anesthetized horses undergoing exploratory laparotomy because of gastrointestinal tract disease. Methods: 11 horses (mean +/- SD, 10.3 +/- 7.4 years; 526 +/- 40 kg). Methods: Lidocaine hydrochloride (loading infusion, 1.3 mg/kg during a 15-minute period [87.5 microg/kg/min]; maintenance infusion, 50 microg/kg/min for 60 to 90 minutes) was administered IV to dorsally recumbent anesthetized horses. Blood samples were collected before and at fixed time points during and after lidocaine infusion for analysis of serum drug concentration...
Wettstein D, Moens Y, Jaeggin-Schmucker N, Böhm SH, Rothen HU, Mosing M, Kästner SB, Schatzmann U.To evaluate pulmonary and cardiovascular effects of a recruitment maneuver (RM) combined with positive end-expiratory pressure (PEEP) during total intravenous anesthesia in ponies. Methods: 6 healthy adult Shetland ponies. Methods: After premedication with detomidine (10 microg/kg, IV), anesthesia was induced with climazolam (0.06 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with a constant rate infusion of detomidine (0.024 mg/kg/h), climazolam (0.036 mg/kg/h), and ketamine (2.4 mg/kg/h). The RM was preceded by an incremental PEEP titration and followed by a decremental PEEP titrati...
Malone E, Ensink J, Turner T, Wilson J, Andrews F, Keegan K, Lumsden J.To determine if intravenous lidocaine is useful and safe as a treatment for equine ileus. Methods: Prospective double-blinded placebo-controlled trial. Methods: Horses (n = 32) with a diagnosis of postoperative ileus (POI) or enteritis and that had refluxed >20 L or had been refluxing for >24 hours. Methods: Refluxing horses were administered lidocaine (1.3 mg/kg intravenously [IV] as a bolus followed by a 0.05 mg/kg/min infusion) or saline (0.9% NaCl) solution placebo for 24 hours. Variables evaluated included volume and duration of reflux, time to 1st fecal passage, signs of pain, anal...
Rubio-Martínez LM, López-Sanromán J, Cruz AM, Santos M, Andrés MS, Román FS.To evaluate clinical variables, regional concentrations, and pharmacokinetics of vancomycin in the synovial fluid of distal forelimb joints of horses after IV regional limb perfusion. Methods: 6 horses. Methods: Vancomycin was administered via IV regional limb perfusion to the distal portion of the forelimbs of anesthetized horses. Drug (300 mg of vancomycin hydrochloride in 60 mL of saline [0.9% NaCl] solution) was infused into 1 forelimb, whereas the contralateral limb served as a control and was perfused with 60 mL of saline solution. Solutions were injected into the lateral digital vein af...
Dunkel B, Palmer JE, Olson KN, Boston RC, Wilkins PA.Foals may present to a referral hospital with the primary diagnosis of uroperitoneum (UP), or they may develop UP while hospitalized for other reasons. Historical, physical, laboratory, and diagnostic variables of foals presenting with UP were compared to those developing UP while hospitalized. Emphasis was placed on the presence of electrolyte abnormalities, evidence of sepsis or infection, and development of anesthetic complications during surgical correction of the defect. Foals developing UP while in the hospital frequently had a history of dystocia and presented at a very young age (< ...
Pille F, De Baere S, Ceelen L, Dewulf J, Croubels S, Gasthuys F, De Backer P, Martens A.To determine radiocarpal (RC) joint synovial fluid and plasma ceftiofur concentrations after regional intravenous perfusion (RIP) and systemic intravenous (IV) administration. Methods: Experimental cross-over study. Methods: Five normal adult horses. Methods: One RC joint was randomly selected for RIP and the contralateral RC joint was sampled to determine intrasynovial ceftiofur concentrations after IV administration. Wash-out between IV and RIP was > or = 14 days. After surgical introduction of an intraarticular catheter, ceftiofur (2 g) was administered under general anesthesia either IV or...
Rubio-Martínez L, López-Sanromán J, Cruz AM, Santos M, San Román F.To study the pharmacokinetics of vancomycin in plasma obtained from the medullary sinusoids of the proximal phalanx (P1) after intravenous (IV) and intraosseous (IO) regional limb perfusion (RLP). Methods: Experimental study. Methods: Twelve horses. Methods: IV and IO RLP were performed in 2 groups (n = 6) of horses. Vancomycin hydrochloride (300 mg in 60 mL 0.9% NaCl) was randomly infused in 1 front limb, with the contralateral limb as control (60 mL 0.9% NaCl). A hole was drilled in the lateral cortex of P1, and blood samples from the medullary sinusoids of P1 were collected before infusion,...
Spadavecchia C, Arendt-Nielsen L, Andersen OK, Spadavecchia L, Schatzmann U.To investigate the action of a single IV administration of romifidine on the thresholds of the nociceptive withdrawal reflex (NWR) and temporal summation in conscious horses. Methods: 10 adult horses. Methods: Single electrical stimulations were applied on the digital nerves to evoke NWR from the left forelimb and hind limb. Repeated electrical stimulations (10 stimuli, 5 Hz) were given to obtain temporal summation. Surface electromyographic reflex activity was recorded from the common digital extensor and cranial tibial muscles. After baseline assessment of NWR and temporal summation threshol...
Valverde A, Gunkelt C, Doherty TJ, Giguère S, Pollak AS.Lidocaine constant rate infusions (CRIs) are common as an intraoperative adjunct to general anaesthesia, but their influence on quality of recovery has not been thoroughly determined. Objective: To determine the effects of an intraoperative i.v. CRI of lidocaine on the quality of recovery from isoflurane or sevoflurane anaesthesia in horses undergoing various surgical procedures, using a modified recovery score system. Objective: The administration of intraoperative lidocaine CRI decreases the quality of recovery in horses. Methods: Lidocaine (2 mg/kg bwt bolus followed by 50 microg/kg bwt/min...
Bettschart-Wolfensberger R, Kalchofner K, Neges K, Kästner S, Fürst A.To examine the clinical suitability of medetomidine-propofol infusions for total intravenous anaesthesia in horses. Methods: Fifty client-owned horses of mixed breed, age [mean +/- SD (range)] 6.6 +/- 4.4 (0.04-18) years, mass 478 +/- 168.3 (80-700) kg presented for a range of operations requiring general anaesthesia. Methods: Pre-anaesthetic medication was intravenous (IV) medetomidine 7 mug kg(-1). Anaesthesia was induced with IV ketamine (2 mg kg(-1)) and diazepam (0.02 mg kg(-1)). After endotracheal intubation, O2 was delivered (FiO2 > 0.85). Positive pressure ventilation was initiated if ...
Davis JL, Salmon JH, Papich MG.To determine the pharmacokinetics of itraconazole after IV or oral administration of a solution or capsules to horses and to examine disposition of itraconazole in the interstitial fluid (ISF), aqueous humor, and polymorphonuclear leukocytes after oral administration of the solution. Methods: 6 healthy horses. Methods: Horses were administered itraconazole solution (5 mg/kg) by nasogastric tube, and samples of plasma, ISF, aqueous humor, and leukocytes were obtained. Horses were then administered itraconazole capsules (5 mg/kg), and plasma was obtained. Three horses were administered itraconaz...
Eiler H, Frank N, Andrews FM, Oliver JW, Fecteau KA.To characterize the physiologic response to i.v. bolus injection of glucose and insulin for development of a combined glucose-insulin test (CGIT) in horses. Methods: 6 healthy mares and 1 mare each with pituitary adenoma and urolithiasis. Methods: Horses were given a CGIT (glucose, 150 mg/kg; insulin, 0.1 U/kg); results were compared with a singular i.v. glucose tolerance test (GTT; 150 mg/kg) and a singular i.v. insulin sensitivity test (IST; 0.1 U/kg). Healthy horses were also given a CGIT after receiving xylazine and undergoing stress. Results: Physiologically, the CGIT resulted in a 2-phas...
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 ...
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...
Oijala M, Katila T.Detomidine was administered twice to six foals (14 to 94 days old) using three different doses (10, 20 and 40 micrograms/kg bodyweight intravenously) in a double blind trial. Sedation, analgesia, heart rate and clinically observed side-effects were recorded. Detomidine showed strong sedative effects at all doses tested. Sedation deepened very little by increasing the dose from 10 to 40 micrograms/kg bodyweight, but the duration of the effect was longer. Analgesia was considered good with the largest dose (40 micrograms/kg), and moderate or non-existent with the lower doses. Detomidine caused a...
Duran SH, Ravis WR, Pedersoli WM, Schumacher J.Pharmacokinetics of phenobarbital was examined in 6 mature horses after 12 mg of phenobarbital/kg of body weight was infused over 20 minutes. Biexponential decrease in serum phenobarbital concentrations was observed with a distribution-phase half-life of 0.101 +/- 0.086 hour (mean +/- SD) and a terminal-phase elimination half-life of 18.3 +/- 3.65 hours. The volume of distribution at steady state was 0.803 +/- 0.070 L/kg. Total body clearance of phenobarbital was 30.8 +/- 6.2 ml/h/kg. The high clearance in the horse seems to explain the markedly shorter half-life of phenobarbital in this speci...
King JN, Gerring EL.Dopamine was infused intravenously (1, 5 and 10 micrograms/kg/min) for 60 min in three fasted ponies. A dose-dependent increase in heart rate occurred that was rapid in onset and termination at the start and end of the infusions, respectively. Dose-dependent changes in gastric and small intestinal motility were observed. An initial marked inhibition of gastric contraction amplitude was followed by a secondary prolonged period of activity. At the same time the small intestine showed a prolonged period of irregular activity (phase II) and a marked increase in the interval between successive phas...
Robertson SA, Carter SW, Donovan M, Steele C.The effects of intravenous xylazine hydrochloride on blood glucose, plasma insulin and rectal temperature were investigated in six foals at 10 and 28 days of age. These variables were also measured in three foals at 19 days of age when saline alone was injected. Rectal temperature fell significantly after 30 mins in both groups of xylazine treated foals and was still depressed after 120 mins. Hypothermia did not occur in the saline control group. There was no significant change in blood glucose or plasma insulin concentrations during the 120 mins following either xylazine or saline administrat...
Shane SE, Langston VC, Wills RW, Denney WS, Knych H, Fontenot RL, Meyer RE, Natalini CC.An ideal dexmedetomidine protocol has yet to be determined for standing sedation in horses. It was hypothesized that an IV bolus followed by CRI dexmedetomidine would have a quicker increase in plasma concentrations compared with repeated IM injections. In a crossover design, eight adult, female horses were randomly placed into two groups: the CRI group (IV bolus dexmedetomidine at 0.005 mg/kg followed by a CRI at 0.01 mg/kg/h for 15 min then 0.005 mg/kg/h for 60 min) and the IM group (dexmedetomidine at 0.01 mg/kg, followed by 0.005 mg/kg in 30-min intervals for 60 min). Clearance and...
Yamashita K, Satoh M, Umikawa A, Tsuda A, Yajima Y, Tsubakishita S, Seno T, Katoh S, Izumisawa Y, Kotani T.The anesthetic and cardiovascular effects of a combination of continuous intravenous infusion using a mixture of 100 g/L guaifenesin-4 g/L ketamine-5 mg/L medetomidine (0.25 ml/kg/hr) and oxygen-sevoflurane (OS) anesthesia (GKM-OS anesthesia) in horses were evaluated. The right carotid artery of each of 12 horses was raised surgically into a subcutaneous position under GKM-OS anesthesia (n=6) or OS anesthesia (n=6). The end-tidal concentration of sevoflurane (EtSEV) required to maintain surgical anesthesia was around 1.5% in GKM-OS and 3.0% in OS anesthesia. Mean arterial blood pressure (MABP)...
De Clercq D, Baert K, Croubels S, van Loon G, Maes A, Tavernier R, Deprez P, De Backer P.To determine the clinical effects and pharmacokinetics of amiodarone after single doses of 5 mg/kg administered orally or intravenously. Methods: 6 healthy adult horses. Methods: In a cross over study, clinical signs and electrocardiographic variables were monitored and plasma and urine samples were collected. A liquid chromatography-mass spectrometry method was used to determine the percentage of protein binding and to measure plasma and urine concentrations of amiodarone and the active metabolite desethylamiodarone. Results: No adverse clinical signs were observed. After IV administration, m...
van Duijkeren E, Vulto AG, Sloet van Oldruitenborgh-Oosterbaan MM, Kessels BG, van Miert AS, Breukink HJ.In the present study, the pharmacokinetic parameters of a trimethoprim/sulphachlorpyridazine preparation following intravenous administration, administration by nasogastric tube and administration with concentrate were determined in the horse. Eight adult horses were dosed at 1 week intervals in a sequentially designed study at a dose of 5 mg/kg trimethoprim (TMP) and 25 mg/kg sulphachlorpyridazine (SCP) on all occasions. Plasma concentrations of both drugs were measured serially for 48 h. Pharmacokinetic parameters of clinical importance (distribution and elimination half-lives, clearance, bi...
Winther L, Baptiste KE, Friis C.Ampicillin concentrations in pulmonary epithelial lining fluid (PELF) and plasma was studied after single intravenous ampicillin administration (15mg/kg) or single intragastric administration of its prodrug, pivampicillin (19.9mg/kg) to horses and discussed in relation to minimum inhibitory concentrations (MIC) of common equine respiratory pathogens. After intravenous administration, elimination of ampicillin was fast and not detectable in plasma after 12h in three out of six horses. Pivampicillin was absorbed well in non-fasted horses with an oral bioavailability of 36%. The degree of penetra...
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...
Ingvast-Larsson C, Appelgren LE, Nyman G.After intravenous administration of theophylline, microdialysis has been used for studying the non protein bound theophylline concentration in blood and in lung tissue in the rat as well as in two horses. The distribution pattern of 14C-theophylline in the rat was also investigated. When the distribution of theophylline was completed the time course of free drug in the interstitial fluid in lung tissue was in good agreement with the total concentration-time profile in plasma in both species. In the rat the free concentration of theophylline in the lung was slightly lower than the free concentr...
Serrano-Rodríguez JM, Gómez-Díez M, Esgueva M, Castejón-Riber C, Mena-Bravo A, Priego-Capote F, Ayala N, Caballero JMS, Muñoz A.Pharmacokinetic and pharmacodynamic (PK/PD) properties of the angiotensin-converting enzyme inhibitor (ACEI) benazeprilat have not been evaluated in horses. This study was designed to establish PK profiles for benazepril and benazeprilat after intravenous (IV) and oral (PO) administration of benazepril using a PK/PD model. This study also aims to determine the effects of benazeprilat on serum angiotensin converting enzyme (ACE), selecting the most appropriate dose that suppresses ACE activity. Six healthy horses in a crossover design received IV benazepril at 0.50mg/kg and PO at doses 0 (place...
Schumacher SA, Toribio RE, Scansen B, Lakritz J, Bertone AL.The objectives of this study were to describe pharmacokinetic and pharmacodynamic changes as a result of a single intravenous administration of magnesium sulfate (MgSO ) to healthy horses. MgSO is a magnesium salt that has been used to calm horses in equestrian competition and is difficult to regulate because magnesium is an essential constituent of all mammals. Six healthy adult female horses were administered a single intravenous dose of MgSO at 60 mg/kg of body weight over 5 min. Blood, urine, and cerebrospinal fluid (CSF) samples were collected, and cardiovascular parameters were monitor...
Soma LR, Robinson MA, You Y, Boston RC, Rudy J.Compartmental models were used to investigate the pharmacokinetics of intravenous (i.v.), oral (p.o.), and topical (TOP) administration of dimethyl sulfoxide (DMSO). The plasma concentration-time curve following a 15-min i.v. infusion of DMSO was described by a two-compartment model. Median and range of alpha (t ) and beta (t ) half-lives were 0.029 (0.026-0.093) and 14.1 (6.6-16.4) hr, respectively. Plasma concentration-time curves of DMSO following p.o. and TOP administration were best described by one-compartment absorption and elimination models. Following the p.o. administration, median a...
Kuroda T, Nagata S, Takizawa Y, Tamura N, Kusano K, Mizobe F, Hariu K.The pharmacokinetics of d-chlorpheniramine (CPM), a histamine H1-receptor antagonist, and its ability to inhibit of histamine-induced cutaneous wheal formation, were studied in healthy Thoroughbred horses (n=5). Following an intravenous (IV) dose of 0.5mg/kg bodyweight (BW), plasma drug disposition was very rapid, with the mean terminal half-life and total body clearance calculated as 2.7h and 0.7 L/h/kg, respectively. The observed maximal inhibition of wheal formation following IV doses of 0.1 and 0.5mg/kg BW were 37.8% and 60.6% at 0.5h, respectively. Oral administration of CPM (0.5mg/kg BW)...
Boscan P, Steffey EP, Farver TB, Mama KR, Huang NJ, Harris SB.To compare anesthesia-related events associated with IV administration of 2 novel micellar microemulsion preparations (1% and 5%) and a commercially available formulation (1%) of propofol in horses. Animals-9 healthy horses. Methods: On 3 occasions, each horse was anesthetized with 1 of the 3 propofol formulations (1% or 5% microemulsion or 1% commercial preparation). All horses received xylazine (1 mg/kg, IV), and anesthesia was induced with propofol (2 mg/kg, IV). Induction and recovery events were quantitatively and qualitatively assessed. Venous blood samples were obtained before and at in...
Habershon-Butcher J, Cutler C, Viljanto M, Hincks PR, Biddle S, Paine SW.Xylazine is widely used worldwide as a short-acting sedative in general equine and racing practice. In the UK, although it has a legitimate use during training, equine anti-doping rules state it is a prohibited substance on race day. The aim of the study was to produce a detection time (DT) to better inform European veterinary surgeons so that xylazine can be used appropriately under regulatory rules. Previous publications have various limitations pertaining to analysis method, particularly for plasma and limited length of time of sample collection. In this study, pharmacokinetic data were pro...
Lee YH, Clarke KW, Alibhai HI.Clenbuterol (0.8 microg kg(-1) intravenously) was investigated in ponies (small horses) anaesthetised with acepromazine, detomidine and thiopentone, then halothane in oxygen alone (hyperoxic group) or with nitrous oxide (hypoxic group). Following instrumentation, ponies were placed in dorsal recumbency for 60 minutes, clenbuterol (both groups) or a saline control (hyperoxic group) given, and cardiopulmonary parameters monitored for a further 60 minutes. In the hyperoxic group, clenbuterol administration resulted in a transitory (<five minutes) 15 per cent fall in arterial blood pressure and...
Martín-Jiménez T, Papich MG, Riviere JE.To develop and validate a population pharmacokinetic model for gentamicin in horses, using retrospective clinical data. Methods: 62 horses that had been treated IV with multiple doses of gentamicin at our veterinary teaching hospital between 1987 and 1996. Procedure-46 horses were assigned to the study group, and 16 to the validation group. Detailed history of dosage, sample collection times, and selected pathophysiologic variables were recorded for each patient. Samples were analyzed by use of a fluorescence polarization immunoassay method. Pharmacostatistical analysis was conducted, using co...
Reijerkerk EP, Visser EK, van Reenen CG, van der Kolk JH.To compare the effects of IV administration of various doses of ovine corticotrophin-releasing hormone (oCRH) on plasma and saliva cortisol concentrations in healthy horses and determine whether an oCRH challenge test protocol is valid for use in adult horses. Methods: 24 healthy Warmblood horses. PROCEDURES-Each horse received oCRH in saline (0.9% NaCl) via IV administration at a dose of 0 (control treatment), 0.01, 0.1, or 1.0 Mg/kg (6 horses/group). Jugular blood and saliva samples were collected simultaneously 15 minutes before and immediately prior to injection (baseline); data from these...
Burrows GE, MacAllister CG, Beckstrom DA, Nick JT.The plasma concentrations and pharmacokinetics of rifampin disposition were determined after a single IV, IM, or oral dose of 10 mg/kg of body weight and an oral dose of 25 mg/kg. The overall elimination rate constants per minute were similar for the 10 mg/kg dose (0.0021 +/- 0.0004, IV; 0.0017 +/- 0.0002, IM; and 0.0023 +/- 0.0006, orally). The apparent bioavailability was moderate to low for IM and oral administrations (59.8% +/- 3.2% and 39.5% +/- 5.0%, respectively). The rate of absorption was most rapid for oral administration with an absorption half-life of 249.7 +/- 71.6 minutes as comp...
Sams R, Gerken DF, Ashcraft SM.The pharmacokinetics and urinary excretion of ketoprofen in six healthy mares after the first and last of five daily intravenous doses of 2.2 mg of ketoprofen per kg body weight were investigated using a high-performance liquid chromatographic (HPLC) method for determining plasma and urinary ketoprofen concentrations. Plasma ketoprofen concentrations declined triexponentially after each dose with no significant differences in plasma concentrations or pharmacokinetic parameter values between the first and last doses. The harmonic mean of the terminal elimination half-life of ketoprofen after th...
Garcia Lascurain AA, Sumano Lopez H, Steffey EP, Santillán Doherty P, Hernandez EN.To characterize behavioral and physiological responses to short-term, unsupplemented intravenous (IV) anesthesia in healthy horses at high altitude (2240 m), and to test the hypothesis that the dose of butorphanol modifies the response of the horse to propofol anesthesia following xylazine pre-medication. Methods: Randomized prospective butorphanol dose cross-over experimental design. Animals Eight healthy horses, 13 +/- 6 (mean +/- SD) years of age, and weighing 523 +/- 26 kg. Methods: Each horse was anesthetized three times with at least 3 weeks between each anesthesia. After collecting pre-...
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...
Pass MA, Mogg TD.Amitraz and its active metabolite BTS27271 were given intravenously to ponies and sheep at equimolar doses of 1 mg/kg and 0.68 mg/kg, respectively, and the plasma concentrations of amitraz and BTS27271 estimated at various times thereafter. Amitraz was hydrolysed to BTS27271 in both species. Amitraz was undetectable in sheep plasma after approximately 5 min but persisted in the plasma of ponies for at least 90 min. The persistence of unmetabolized amitraz in ponies may have implications for the toxicity of amitraz in that species. The primary and secondary disposition half-lives of amitraz in ...
Giorgi M, De Vito V, Poapolathep A, Rychshanova R, Sgorbini M, Owen H.Flupirtine (FLU) is a non-opioid analgesic drug, with no antipyretic or anti-inflammatory effects, used in the treatment of a wide range of pain states in human beings. It does not induce the side effects associated with the classical drugs used as pain relievers. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy horses. Six mixed breed adult mares were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received ...
Stewart AJ, Boothe DM, Cruz-Espindola C, Mitchum EJ, Springfield J.To determine the pharmacokinetics of tramadol and its metabolites O-desmethyltramadol (ODT) and N-desmethyltramadol (NDT) in adult horses. Methods: 12 mixed-breed horses. Methods: Horses received tramadol IV (5 mg/kg, over 3 minutes) and orally (10 mg/kg) with a 6-day washout period in a randomized crossover design. Serum samples were collected over 48 hours. Serum tramadol, ODT, and NDT concentrations were measured via high-performance liquid chromatography and analyzed via noncompartmental analysis. Results: Maximum mean ± SEM serum concentrations after IV administration for tramadol, ODT, ...
Brosnan RJ, Steffey EP, Escobar A, Palazoglu M, Fiehn O.To evaluate whether guaifenesin can prevent adverse anesthetic induction events caused by propofol and whether a guaifenesin-propofol induction combination has brief cardiovascular effects commensurate with rapid drug washout. Methods: 8 healthy adult horses. Methods: Guaifenesin was administered IV for 3 minutes followed by IV injection of a bolus of propofol (2 mg/kg). Additional propofol was administered if purposeful movement was detected. Anesthesia was maintained for 2 hours with isoflurane or sevoflurane at 1.2 times the minimum alveolar concentration with controlled normocapnic ventila...
Cuvelliez S, Rosseel G, Blais D, Salmon Y, Troncy E, Larivière N.Intravenous anesthesia in the horse: Comparison of xylazine-ketamine and xylaxine-tiletamine-zolazepam combinations. Six healthy adult horses were anesthetized twice at random with following intravenous combinations: 1.1 mg/kg of body weight (BW) of xylazine followed by 2.2 mg/kg BW of ketamine (X-K) and 1.1 mg/kg BW of xylazine followed by 1.65 mg/kg BW of tiletamine-zolazepam (X-TZ). The modifications of some cardiorespiratory parameters and the duration of anesthesia were evaluated and compared for the 2 protocols used. Few significant differences were observed between the 2 protocols in re...
