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Neudeck S, Twele L, Kopp V, Kästner S. Pharmacodynamics and plasma concentrations of dexmedetomidine with or without vatinoxan as a constant-rate infusion in horses anaesthetized with isoflurane-A pilot study. J Vet Pharmacol Ther 2021; 44:754-765. [PMID: 34159620 DOI: 10.1111/jvp.12992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/13/2021] [Accepted: 06/06/2021] [Indexed: 11/26/2022]
Abstract
The aim was to determine the effects of vatinoxan on dexmedetomidine plasma concentrations and effects on cardiovascular and intestinal tissue pharmacodynamics. In a prospective randomized study, six horses were premedicated intravenously with dexmedetomidine 3.5 µg kg-1 followed by a constant-rate infusion of 7 µg kg-1 h-1 (group DEX) and six horses with dexmedetomidine of the same dose (bolus and constant-rate infusion) combined with vatinoxan 130 µg kg-1 followed by 40 µg kg-1 h-1 (group VAT). Anaesthesia was induced with ketamine and diazepam and maintained with isoflurane. Venous blood samples were withdrawn before and at predefined points in time after drug application. During sedation and anaesthesia, cardiopulmonary variables, gastrointestinal tissue perfusion and oxygenation were recorded. Data were analysed using two-way-ANOVA, unpaired-t-test and Dunnett's-t-test (p < 0.05). Group VAT had significantly higher oxygen delivery and lower oxygen extraction ratio, venous admixture, alveolar dead space and alveolar-arterial-oxygen difference. Tissue perfusion of buccal mucosa was reduced during anaesthesia in group DEX. Plasma concentrations of dexmedetomidine in group VAT (n = 6) and group DEX (n = 5) were comparable between groups. In the present pilot study, co-administration of vatinoxan with dexmedetomidine did not alter plasma concentrations of dexmedetomidine but ameliorated tissue perfusion and global oxygenation variables.
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Affiliation(s)
- Stephan Neudeck
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Lara Twele
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Veronika Kopp
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Sabine Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.,Clinic for Small Animals, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
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Bouillon J, Duke T, Focken AP, Snead EC, Cosford KL. Effects of dexmedetomidine on glucose homeostasis in healthy cats. J Feline Med Surg 2020; 22:344-349. [PMID: 31090471 PMCID: PMC10814663 DOI: 10.1177/1098612x19847282] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Alpha(α)2-agonist administration has been documented to increase blood glucose concentrations in many species. The aim of this study was to further describe the effect of dexmedetomidine on glucose and its regulatory hormones in healthy cats. METHODS A randomized crossover study using eight healthy cats with a 14 day washout period was used to assess the effect of dexmedetomidine (10 μg/kg IV) and saline on glucose, cortisol, insulin, glucagon and non-esterified fatty acid (NEFA) concentrations at 0, 20, 60, 120 and 180 mins post-administration. Glucose:insulin ratios were calculated for each time point. RESULTS Within the dexmedetomidine group, significant differences (P <0.05) were detected: increased median (range) blood glucose concentrations at 60 mins (11.55 mmol/l [5.9-16.6 mmol/l]) and 120 mins (12.0 mmol/l [6.1-13.8 mmol/l]) compared with baseline (6.05 mmol/l [4.8-13.3 mmol/l]); decreased glucagon concentrations at 120 mins (3.8 pmol/l [2.7-8.8 pmol/l]) and 180 mins (4.7 pmol/l [2.1-8.2 pmol/l]) compared with baseline (11.85 pmol/l [8.3-17.2 pmol/l]); decreased NEFA concentrations at 60 mins (0.281 mmol/l [0.041-1.357 mmol/l]) and 120 mins (0.415 mmol/l [0.035-1.356 mmol/l]) compared with baseline (0.937 mmol/l [0.677-1.482 mmol/l]); and significantly larger (P <0.05) glucose:insulin ratios at 60 mins compared with baseline. Insulin and cortisol concentrations were not significantly changed after dexmedetomidine administration. CONCLUSIONS AND RELEVANCE Feline practitioners should be aware of the endocrine effects associated with the use of α2-agonists, particularly when interpreting blood glucose concentrations. The transient effects of dexmedetomidine on glucose homeostasis are unlikely to significantly affect clinical practice.
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Affiliation(s)
- Juliette Bouillon
- Small Animal Clinical Sciences, Western College of Veterinary Medicine/University of Saskatchewan, Saskatoon, Canada
| | - Tanya Duke
- Small Animal Clinical Sciences, Western College of Veterinary Medicine/University of Saskatchewan, Saskatoon, Canada
| | - Alexandra P Focken
- Small Animal Clinical Sciences, Western College of Veterinary Medicine/University of Saskatchewan, Saskatoon, Canada
| | - Elisabeth C Snead
- Small Animal Clinical Sciences, Western College of Veterinary Medicine/University of Saskatchewan, Saskatoon, Canada
| | - Kevin L Cosford
- Small Animal Clinical Sciences, Western College of Veterinary Medicine/University of Saskatchewan, Saskatoon, Canada
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Pypendop BH, Ahokoivu H, Honkavaara J. Pharmacokinetics of vatinoxan in male neutered cats anesthetized with isoflurane. Vet Anaesth Analg 2019; 47:70-75. [PMID: 31806431 DOI: 10.1016/j.vaa.2019.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/04/2019] [Accepted: 10/05/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To characterize the pharmacokinetics of vatinoxan in isoflurane-anesthetized cats. STUDY DESIGN Prospective experimental study. ANIMALS A group of six adult healthy male neutered cats. METHODS Cats were anesthetized using isoflurane in oxygen. Venous catheters were placed to administer the drug and sample blood. Vatinoxan, 1 mg kg-1, was administered intravenously over 5 minutes. Blood was sampled before and at various times during and up to 8 hours after vatinoxan administration. Plasma vatinoxan concentration was measured using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-concentration data using population methods and nonlinear mixed effect modeling. RESULTS A three-compartment model best fitted the data. Typical value (% interindividual variability) for the three volumes (mL kg-1), the metabolic clearance and two distribution clearances (mL minute-1 kg-1) were 34 (55), 151 (35), 306 (18), 2.3 (34), 42.6 (25) and 5.6 (0), respectively. Hypotension increased the second distribution clearance to 10.6. CONCLUSION AND CLINICAL RELEVANCE The pharmacokinetics of vatinoxan in anesthetized cats were characterized by a small volume of distribution and a low clearance. An intravenous bolus of 100 μg kg-1 of vatinoxan followed by constant rate infusions of 55 μg kg-1 minute-1 for 20 minutes, then 22 μg kg-1 minute-1 for 60 minutes and finally 10 μg kg-1 minute-1 for the remainder of the infusion time is expected to maintain the plasma concentration within 90%-110% of the plasma vatinoxan concentration previously shown to attenuate the cardiovascular effects of dexmedetomidine (25 μg kg-1) in conscious cats.
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Affiliation(s)
- Bruno H Pypendop
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Hanna Ahokoivu
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Juhana Honkavaara
- Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA, USA
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Honkavaara JM, Raekallio MR, Syrja PM, Pypendop BH, Knych HK, Kallio-Kujala IJ, Vainio OM. Concentrations of medetomidine enantiomers and vatinoxan, an α 2-adrenoceptor antagonist, in plasma and central nervous tissue after intravenous coadministration in dogs. Vet Anaesth Analg 2019; 47:47-52. [PMID: 31761600 DOI: 10.1016/j.vaa.2019.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/19/2019] [Accepted: 07/27/2019] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To quantify the peripheral selectivity of vatinoxan (L-659,066, MK-467) in dogs by comparing the concentrations of vatinoxan, dexmedetomidine and levomedetomidine in plasma and central nervous system (CNS) tissue after intravenous (IV) coadministration of vatinoxan and medetomidine. STUDY DESIGN Experimental, observational study. ANIMALS A group of six healthy, purpose-bred Beagle dogs (four females and two males) aged 6.5 ± 0.1 years (mean ± standard deviation). METHODS All dogs were administered a combination of medetomidine (40 μg kg-1) and vatinoxan (800 μg kg-1) as IV bolus. After 20 minutes, the dogs were euthanized with an IV overdose of pentobarbital (140 mg kg-1) and both venous plasma and CNS tissues (brain, cervical and lumbar spinal cord) were harvested. Concentrations of dexmedetomidine, levomedetomidine and vatinoxan in all samples were quantified by liquid chromatography-tandem mass spectrometry and data were analyzed with nonparametric tests with post hoc corrections where appropriate. RESULTS All dogs became deeply sedated after the treatment. The CNS-to-plasma ratio of vatinoxan concentration was approximately 1:50, whereas the concentrations of dexmedetomidine and levomedetomidine in the CNS were three- to seven-fold of those in plasma. CONCLUSIONS AND CLINICAL RELEVANCE With the doses studied, these results confirm the peripheral selectivity of vatinoxan in dogs, when coadministered IV with medetomidine. Thus, it is likely that vatinoxan preferentially antagonizes α2-adrenoceptors outside the CNS.
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Affiliation(s)
- Juhana M Honkavaara
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
| | - Marja R Raekallio
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Pernilla M Syrja
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Bruno H Pypendop
- Department of Radiological and Surgical Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Heather K Knych
- Kenneth L. Maddy Equine Analytical Chemistry Laboratory, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Ira J Kallio-Kujala
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Outi M Vainio
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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Pypendop BH, Ahokoivu H, Honkavaara J. Pharmacokinetics of dexmedetomidine during administration of vatinoxan in male neutered cats anesthetized with isoflurane. J Vet Pharmacol Ther 2019; 43:1-5. [PMID: 31318080 DOI: 10.1111/jvp.12796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/13/2019] [Accepted: 06/24/2019] [Indexed: 01/06/2023]
Abstract
Dexmedetomidine is an alpha-2 adrenoceptor agonist, and vatinoxan is an alpha-2 antagonist believed to poorly cross the blood-brain barrier in cats. Dexmedetomidine-vatinoxan combinations are of interest in anesthetized cats because the anesthetic sparing effect of dexmedetomidine may be preserved while vatinoxan attenuates the adverse cardiovascular effects of dexmedetomidine. The aim of this study was to characterize the pharmacokinetics of dexmedetomidine in cats during administration of isoflurane and vatinoxan. Six healthy adult male castrated cats were anesthetized with isoflurane in oxygen. Vatinoxan was administered using a target-controlled infusion system intended to maintain a plasma concentration of 4 µg/ml. Dexmedetomidine, 35 µg/kg was administered intravenously over 5 min. Plasma dexmedetomidine and vatinoxan concentrations were measured at selected time points ranging from prior to 8 hr after dexmedetomidine administration using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-concentration data using nonlinear mixed-effect modeling. A three-compartment model best fitted the data. Typical value (% interindividual variability) for the three-compartment volumes (ml/kg), the metabolic clearance and the two intercompartment distribution clearances (ml min-1 kg-1 ) were 168 (259), 318 (35), 1,425 (18), 12.4 (31), 39.1 (18), and 29.6 (17), respectively. Mean ± standard deviation plasma vatinoxan concentration was 2.6 ± 0.6 µg/ml.
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Affiliation(s)
- Bruno H Pypendop
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Hanna Ahokoivu
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Juhana Honkavaara
- School of Veterinary Medicine, Veterinary Medical Teaching Hospital, University of California, Davis, CA, USA
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Pypendop BH, Ahokoivu H, Honkavaara J. Effects of dexmedetomidine, with or without vatinoxan (MK-467), on minimum alveolar concentration of isoflurane in cats. Vet Anaesth Analg 2019; 46:443-451. [PMID: 30982711 DOI: 10.1016/j.vaa.2019.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 02/10/2019] [Accepted: 02/10/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To characterize the effects of dexmedetomidine, with or without vatinoxan, on the minimum alveolar concentration of isoflurane (MACISO) in cats. STUDY DESIGN Randomized crossover experimental study. ANIMALS A group of six adult healthy male neutered cats. METHODS Cats were anesthetized with isoflurane in oxygen and instrumented. Dexmedetomidine was administered using a target-controlled infusion system to achieve 10 target plasma concentrations ranging from 0 to 40 ng mL-1. Additionally, vatinoxan or an equivalent volume of saline was administered using a target-controlled infusion system to achieve a target plasma concentration of 4 μg mL-1. Pulse rate (PR), respiratory rate, systolic arterial pressure (SAP), hemoglobin oxygen saturation, body temperature, end-tidal partial pressure of carbon dioxide and drug concentrations were measured. MACISO was determined at each target plasma dexmedetomidine concentration using the bracketing method and the tail clamp technique. Pharmacodynamic models were fitted to the plasma dexmedetomidine concentration-MACISO. Pharmacodynamic parameters were tested for equivalence, and if rejected, for difference. RESULTS Dexmedetomidine alone decreased MACISO in a plasma concentration-dependent manner. Maximum reduction was 77 ± 4%; the dexmedetomidine concentration producing 50% of the maximum decrease (IC50) was 0.77 ng mL-1. Vatinoxan increased MACISO in the absence of dexmedetomidine, decreased the potency of dexmedetomidine for its MACISO-reducing effect (IC50 = 12 ng mL-1) and lessened the maximum MACISO reduction (60 ± 14%). PR decreased less and SAP increased less when dexmedetomidine was administered with vatinoxan compared with saline. CONCLUSION AND CLINICAL RELEVANCE Vatinoxan altered the effect of dexmedetomidine on MACISO. A high plasma dexmedetomidine concentration in the presence of vatinoxan resulted in a large decrease in MACISO, with attenuation of dexmedetomidine-induced cardiovascular effects. The vatinoxan-dexmedetomidine combination may provide clinical benefits in isoflurane-anesthetized cats.
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Affiliation(s)
- Bruno H Pypendop
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Hanna Ahokoivu
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Juhana Honkavaara
- William R Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA, USA
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Cardiopulmonary effects of dexmedetomidine, with and without vatinoxan, in isoflurane-anesthetized cats. Vet Anaesth Analg 2019; 46:753-764. [PMID: 31416697 DOI: 10.1016/j.vaa.2019.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/27/2019] [Accepted: 05/30/2019] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To characterize the cardiopulmonary effects of dexmedetomidine, with or without vatinoxan, in isoflurane-anesthetized cats. STUDY DESIGN Randomized, crossover experimental study. ANIMALS A group of six adult healthy male neutered cats. METHODS Cats were instrumented during anesthesia with isoflurane in oxygen. Isoflurane end-tidal concentration was set to 1.25 minimum alveolar concentration (MAC). Dexmedetomidine was administered using a target-controlled infusion system to achieve and maintain 10 target plasma concentrations ranging from 0 to 40 ng mL-1. Furthermore, vatinoxan or an equivalent volume of saline was administered using a target-controlled infusion system to achieve and maintain a target plasma concentration of 4 μg mL-1. Isoflurane concentration was adjusted after each change in dexmedetomidine concentration to maintain a concentration equivalent to 1.25 MAC. Heart rate (HR), arterial blood pressure, central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary artery occlusion pressure (PAOP), body temperature, cardiac output, arterial and mixed-venous blood gas and pH and drug concentrations were measured. Additional variables were calculated from the measurements. RESULTS Dexmedetomidine alone resulted in decreased HR, cardiac index, stroke index and oxygen delivery, and increased systolic, mean (MAP) and diastolic arterial pressure, CVP, PAP, PAOP, systemic vascular resistance index, rate-pressure product, left ventricular stroke work index and oxygen extraction ratio. Vatinoxan resulted in severe hypotension at target plasma dexmedetomidine concentrations <10 ng mL-1. Vatinoxan attenuated the cardiovascular effects of dexmedetomidine at the 10 and 20 ng mL-1 targets, but MAP could be maintained above 60 mmHg only when isoflurane concentration was <1.25 MAC. Less improvement in cardiovascular function was seen with vatinoxan at the 40 ng mL-1 target plasma dexmedetomidine concentration. CONCLUSIONS AND CLINICAL RELEVANCE Vatinoxan, at the plasma concentration maintained in this study, attenuated the cardiovascular effects of dexmedetomidine in isoflurane-anesthetized cats. However, its administration resulted in hypotension, which may limit its clinical usefulness.
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Adam M, Raekallio MR, Salla KM, Honkavaara JM, Männikkö S, Scheinin M, Kajula M, Mölsä SH, Vainio OM. Effects of the peripherally acting α2-adrenoceptor antagonist MK-467 on cardiopulmonary function in sheep sedated by intramuscular administration of medetomidine and ketamine and reversed by intramuscular administration of atipamezole. Am J Vet Res 2018; 79:921-932. [DOI: 10.2460/ajvr.79.9.921] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Martin-Flores M, Sakai DM, Honkavaara J, Campoy L, Portela DA, Gleed RD. Hemodynamic effects of MK-467 following intravenous administration to isoflurane-anesthetized cats concurrently receiving dexmedetomidine. Am J Vet Res 2018; 79:711-717. [DOI: 10.2460/ajvr.79.7.711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Pascoe PJ, Pypendop BH, Pavez Phillips JC, DiMaio Knych HK, Sanchez-Migallon Guzman D, Hawkins MG. Pharmacokinetics of fentanyl after intravenous administration in isoflurane-anesthetized red-tailed hawks (Buteo jamaicensis) and Hispaniolan Amazon parrots (Amazona ventralis). Am J Vet Res 2018; 79:606-613. [DOI: 10.2460/ajvr.79.6.606] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Pypendop BH, Honkavaara J, Ilkiw JE. Pharmacokinetics of dexmedetomidine, MK-467 and their combination following intramuscular administration in male cats. Vet Anaesth Analg 2017; 44:823-831. [DOI: 10.1016/j.vaa.2017.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 10/19/2022]
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The impact of MK-467 on sedation, heart rate and arterial blood pressure after intramuscular coadministration with dexmedetomidine in conscious cats. Vet Anaesth Analg 2017; 44:811-822. [DOI: 10.1016/j.vaa.2016.08.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 07/30/2016] [Accepted: 08/24/2016] [Indexed: 12/28/2022]
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Honkavaara J, Pypendop B, Turunen H, Ilkiw J. The effect of MK-467, a peripheral α2-adrenoceptor antagonist, on dexmedetomidine-induced sedation and bradycardia after intravenous administration in conscious cats. Vet Anaesth Analg 2017; 44:42-51. [DOI: 10.1111/vaa.12385] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/15/2016] [Indexed: 12/16/2022]
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