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de Sant'Ana Alves L, Arcoverde KN, de Oliveira CVA, Cavalcante JM, Araújo-Silva G, de Paula VV. Pharmacokinetics and pharmacodynamics of intravenous dexmedetomidine (2 μg∙kg -1) in dogs. Res Vet Sci 2024; 171:105229. [PMID: 38507826 DOI: 10.1016/j.rvsc.2024.105229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 02/08/2024] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
This study assessed the pharmacokinetics and pharmacodynamics of low-dose dexmedetomidine after IV bolus in dogs. Six healthy adult dogs (6.8 ± 3.0 kg) received dexmedetomidine (2 μg.kg-1 IV) over 2 min, using an infusion pump. Blood samples were collected totaling 5 h of monitoring. A validated UHPLC-MS/MS method was used to determine the plasma concentration of dexemedetomidine. For pharmacodynamics, HR, RR, oscillometric MBP, Grint END sedation score were evaluated at baseline (T0), every 3 min (T3 to T21), and after 30 (T30) and 60 (T60) minutes, with p < 0.05. T1/2 was 28.28 ± 6.14 min; the area under the curve was 467.44 ± 60.42 ng/mL/min. The total clearance was 5.46 ± 0.41 mL/min/kg, the Vdss was 146.19 ± 21.04 mL/kg, and the C max was 3.13 ± 1.15 ng/mL. HR (bpm) decreased significantly from T6 (79 ± 21) to T21 (78 ± 31) compared to T0 (116 ± 28). RR(mpm) decreased from T3 (43 ± 44) to T60 (41 ± 23), with T0 being 70 ± 48. The MBP (mmHg) increased at T18 (151 ± 34), T21 (152 ± 35), and T30 (140 ± 27), compared to T0 (111 ± 22). Sedation occurred at all times post-bolus, with a maximum peak at T12 (END 8 ± 6). The low dose of dexmedetomidine provided sedation in all animals, characterizing rapid metabolization and elimination. However, cardiovascular effects still may have negative repercussions in dogs with hemodynamic comorbidities, highlighting the caution and individualization of its use in certain patients.
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Affiliation(s)
- Larissa de Sant'Ana Alves
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, 572, Rua Francisco Mota, Presidente Costa e Silva, Mossoró, RN 59625-900, Brazil
| | - Kathryn Nóbrega Arcoverde
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, 572, Rua Francisco Mota, Presidente Costa e Silva, Mossoró, RN 59625-900, Brazil
| | - Caio Vinícius Almeida de Oliveira
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, 572, Rua Francisco Mota, Presidente Costa e Silva, Mossoró, RN 59625-900, Brazil
| | - Jerson Marques Cavalcante
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, 572, Rua Francisco Mota, Presidente Costa e Silva, Mossoró, RN 59625-900, Brazil
| | - Gabriel Araújo-Silva
- Universidade do Estado do Amapá, 650, Avenida Presidente Vargas, Centro, Macapá, AP 68.900-070, Brazil
| | - Valéria Veras de Paula
- Department of Animal Science, Universidade Federal Rural do Semi-Árido, 572, Rua Francisco Mota, Presidente Costa e Silva, Mossoró, RN 59625-900, Brazil.
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Levionnois OL, Barbarossa A, Bardhi A, Siegenthaler J, Forss Pleyers T, Guidi M, Spadavecchia C, Raillard M. Enantiospecific pharmacokinetics of intravenous dexmedetomidine in beagles. J Vet Pharmacol Ther 2022; 45:366-372. [PMID: 35484944 PMCID: PMC9543782 DOI: 10.1111/jvp.13063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/12/2022] [Accepted: 04/15/2022] [Indexed: 11/30/2022]
Abstract
The goal of this study was to investigate the pharmacokinetic (PK) behaviour of dexmedetomidine in dogs administered as a pure enantiomer versus as part of a racemic mixture. Eight unmedicated intact purpose‐bread beagles were included. Two intravenous treatments of either medetomidine or dexmedetomidine were administered at 10‐ to 14‐day intervals. Atipamezole or saline solution was administered intramuscularly 45 min later. Venous blood samples were collected into EDTA collection tubes, and the quantification of dexmedetomidine and levomedetomidine was performed by chiral LC–MS/MS. All dogs appeared sedated after each treatment without complication. Plasma concentrations of levomedetomidine were measured only in the racemic group and were 51.4% (51.4%–56.1%) lower than dexmedetomidine. Non‐compartmental analysis (NCA) was performed for both drugs, while dexmedetomidine data were further described using a population pharmacokinetic approach. A standard two‐compartment mammillary model with linear elimination with combined additive and multiplicative error model for residual unexplained variability was established for dexmedetomidine. An exponential model was finally retained to describe inter‐individual variability on parameters of clearance (Cl1) and central and peripheral volumes of distribution (V1, V2). No effect of occurrence, levomedetomidine or atipamezole could be observed on dexmedetomidine PK parameters. Dexmedetomidine did not undergo significantly different PK when administered alone or as part of the racemic mixture in otherwise unmedicated dogs.
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Affiliation(s)
- Olivier Louis Levionnois
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Andrea Barbarossa
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Anisa Bardhi
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Joelle Siegenthaler
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Tekla Forss Pleyers
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Monia Guidi
- Service of Clinical Pharmacology, Department of Laboratory Medicine and Pathology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,Center for Research and Innovation in Clinical Pharmaceutical Sciences, Teaching and Research Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Claudia Spadavecchia
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Mathieu Raillard
- Section of Anaesthesiology and Pain Therapy, Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Tashiro M, Tohei A. Recommended doses of medetomidine-midazolam-butorphanol with atipamezole for preventing hypothermia in mice. J Vet Med Sci 2022; 84:445-453. [PMID: 35135936 PMCID: PMC8983292 DOI: 10.1292/jvms.21-0479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A non-narcotic anesthetic combination (Me/Mi/Bu) of medetomidine (Me), midazolam (Mi), and butorphanol (Bu) has been recommended as the injectable anesthesia in mice. An original dose of Me/Mi/Bu (0.3/4.0/5.0 mg/kg) has provided sufficient anesthetic duration of 40–50 min in mice. In addition, atipamezole is available for reversal of Me/Mi/Bu anesthesia. As an adverse effect of Me/Mi/Bu anesthesia, however, severe hypothermia has been also observed in mice. In the present study, we investigated 1) the main agent in Me/Mi/Bu to cause of hypothermia, 2) the effects of the differential doses of atipamezole on hypothermia induced by Me/Mi/Bu anesthesia and on the plasma levels of creatinine phosphokinase and transaminases, and 3) those recommended doses for preventing hypothermia induced by Me/Mi/Bu anesthesia in mice. The results suggested that 1) the α2-agonist medetomidine is most likely to induce hypothermia in mice under Me/Mi/Bu anesthesia, 2) the antagonism of atipamezole within proper dose range is effective in promoting the recovery from Me/Mi/Bu-induced hypothermia, and 3) Me/Mi/Bu at the recommended dose of 0.2/6.0/10.0 mg/kg enable to provide anesthetic effects for 40 min and is more considerable to prevent the hypothermia than that at the original dose of 0.3/4.0/5.0 mg/kg.
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Affiliation(s)
- Mizuho Tashiro
- Laboratory of Experimental Animal Science, Nippon Veterinary and Life Science University
| | - Atsushi Tohei
- Laboratory of Experimental Animal Science, Nippon Veterinary and Life Science University
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Ferraro MA, Molina CV, Gris VN, Kierulff MCM, Cortopassi SRG. Vasectomy of golden-headed lion tamarins (Leontopithecus chrysomelas) using local anesthesia after sedation with dexmedetomidine-ketamine-meperidine. J Med Primatol 2021; 51:53-55. [PMID: 34693530 DOI: 10.1111/jmp.12547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/17/2021] [Accepted: 09/26/2021] [Indexed: 11/27/2022]
Abstract
The study evaluated the combination of ketamine, dexmedetomidine, and meperidine for vasectomy in golden-headed lion tamarins. Lidocaine infiltration was required for intraoperative analgesia and atipamezole was used at the end of the procedure. The protocol promoted satisfactory sedation and analgesia with a short recovery time in tamarins.
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Affiliation(s)
- Mario Antonio Ferraro
- Department of Veterinary Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil
| | - Camila Vieira Molina
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Vanessa Nadine Gris
- Department of Veterinary Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.,Center for Human Evolution Modeling Research, Primate Research Institute, Kyoto University, Inuyama, Japan
| | | | - Silvia Renata Gaido Cortopassi
- Department of Veterinary Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil
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Nicolás-Barceló P, Facchin M, Martínez-Taboada F, Barrera R, Cristóbal JI, González MA, Durán-Galea Á, Macías-García B, Duque FJ. Effects of Sedation with Medetomidine and Dexmedetomidine on Doppler Measurements of Ovarian Artery Blood Flow in Bitches. Animals (Basel) 2021; 11:ani11020538. [PMID: 33669625 PMCID: PMC7922352 DOI: 10.3390/ani11020538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 11/16/2022] Open
Abstract
The aim was to evaluate if medetomidine and dexmedetomidine affected arterial ovarian blood flow in dogs. The dogs were randomly assigned to two different groups. In Group 1, medetomidine (10 µg/kg) was administered intramuscularly and, in Group 2, dexmedetomidine (5 µg/kg) was used. After a preliminary exam, arterial blood pressure (BP) was measured and a duplex Doppler ultrasonographic examination of both ovarian arteries was performed. Twenty minutes after the administration of medetomidine or dexmedetomidine, BP and ovarian Doppler ultrasonography were repeated. High quality tracings of ovarian artery flow velocity were obtained in all dogs and Doppler parameters: Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV) and Resistive Index (RI) were measured before and after drug administration in the left (LO) and right (RO) ovaries. PSV and EDV values decreased significantly after drug administration (p < 0.05) compared to the non-sedated values, but no differences were found between the LO and RO (p > 0.05). The RI was not affected by drugs administration in neither of the groups studied (p > 0.05). In conclusion, the administration of medetomidine or dexmedetomidine causes a decrease in blood flow velocity in the ovarian artery and may be a good choice to avoid excessive bleeding prior surgeries in which ovariectomy.
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Affiliation(s)
- Paloma Nicolás-Barceló
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - Martina Facchin
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - Fernando Martínez-Taboada
- Department of Veterinary Anaesthesia and Analgesia, School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 3260, Australia;
| | - Rafael Barrera
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - José Ignacio Cristóbal
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - Mario Alberto González
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - Ángela Durán-Galea
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
| | - Beatriz Macías-García
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
- Correspondence:
| | - Francisco Javier Duque
- Veterinary Teaching Hospital, University of Extremadura, 10003 Cáceres, Spain; (P.N.-B.); (M.F.); (R.B.); (J.I.C.); (M.A.G.); (Á.D.-G.); (F.J.D.)
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Evaluation of alfaxalone and midazolam with or without flumazenil reversal in Egyptian fruit bats (Rousettus aegyptiacus). Vet Anaesth Analg 2020; 48:239-246. [PMID: 33451926 DOI: 10.1016/j.vaa.2020.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To evaluate alfaxalone-midazolam anesthesia in Egyptian fruit bats (Rousettus aegyptiacus) and the effect of flumazenil administration on recovery time and quality. STUDY DESIGN Randomized, blinded, crossover and controlled, experimental trial. ANIMALS A total of 10 male Egyptian fruit bats. METHODS Bats were anesthetized with alfaxalone (15 mg kg-1) and midazolam (2 mg kg-1) administered subcutaneously. During anesthesia, vital signs, muscle tone and reflexes were monitored every 10 minutes. Flumazenil (0.3 mg kg-1) or saline at an equal volume was administered subcutaneously 60 minutes after anesthetic administration. Time to induction, time to first movement and recovery time (flying) were measured. Quality of induction, anesthesia and recovery were assessed on a 1-3 scale (1, poor; 2, good; 3, excellent). RESULTS Time to induction was 4.2 ± 1.9 minutes (mean ± standard deviation), with median quality score of 2 (range, 1-3). Anesthesia quality score was 3 (1-3). During anesthesia, heart rate and respiratory frequency decreased significantly and penis relaxation, indicating muscle tone, increased significantly. Administration of flumazenil significantly reduced mean recovery time compared with saline (10 ± 5 versus 45 ± 17 minutes, respectively), and significantly improved the quality of recovery [2.5 (2-3) versus 1 (1-2), respectively]. CONCLUSIONS AND CLINICAL RELEVANCE Alfaxalone-midazolam anesthesia resulted in good induction, muscle relaxation and sufficient anesthesia to perform routine diagnostic and therapeutic procedures for approximately 40 minutes. Reversal of midazolam with flumazenil is recommended, resulting in quicker and better recovery.
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Turunen H, Raekallio MR, Honkavaara JM, Restitutti F, Kallio-Kujala IJ, Adam M, Nevanperä K, Scheinin M, Männikkö SK, Hautajärvi HJ, Larenza Menzies P, Vainio OM. Cardiovascular and sedation reversal effects of intramuscular administration of atipamezole in dogs treated with medetomidine hydrochloride with or without the peripheral α 2-adrenoceptor antagonist vatinoxan hydrochloride. Am J Vet Res 2019; 80:912-922. [PMID: 31556714 DOI: 10.2460/ajvr.80.10.912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the cardiovascular and sedation reversal effects of IM administration of atipamezole (AA) in dogs treated with medetomidine hydrochloride (MED) or MED and vatinoxan (MK-467). ANIMALS 8 purpose-bred, 2-year-old Beagles. PROCEDURES A randomized, blinded, crossover study was performed in which each dog received 2 IM treatments at a ≥ 2-week interval as follows: injection of MED (20 μg/kg) or MED mixed with 400 μg of vatinoxan/kg (MEDVAT) 30 minutes before AA (100 μg/kg). Sedation score, heart rate, mean arterial and central venous blood pressures, and cardiac output were recorded before and at various time points (up to 90 minutes) after AA. Cardiac and systemic vascular resistance indices were calculated. Venous blood samples were collected at intervals until 210 minutes after AA for drug concentration analysis. RESULTS Heart rate following MED administration was lower, compared with findings after MEDVAT administration, prior to and at ≥ 10 minutes after AA. Mean arterial blood pressure was lower with MEDVAT than with MED at 5 minutes after AA, when its nadir was detected. Overall, cardiac index was higher and systemic vascular resistance index lower, indicating better cardiovascular function, in MEDVAT-atipamezole-treated dogs. Plasma dexmedetomidine concentrations were lower and recoveries from sedation were faster and more complete after MEDVAT treatment with AA than after MED treatment with AA. CONCLUSIONS AND CLINICAL RELEVANCE Atipamezole failed to restore heart rate and cardiac index in medetomidine-sedated dogs, and relapses into sedation were observed. Coadministration of vatinoxan with MED helped to maintain hemodynamic function and hastened the recovery from sedation after AA in dogs.
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Gozalo-Marcilla M, Moreira da Silva R, Pacca Loureiro Luna S, Rodrigues de Oliveira A, Werneck Fonseca M, Peporine Lopes N, Taylor PM, Pelligand L. A possible solution to model nonlinearity in elimination and distributional clearances with α 2 -adrenergic receptor agonists: Example of the intravenous detomidine and methadone combination in sedated horses. J Vet Pharmacol Ther 2019; 42:738-744. [PMID: 31584710 DOI: 10.1111/jvp.12815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 08/22/2019] [Accepted: 08/30/2019] [Indexed: 12/28/2022]
Abstract
The alpha(α)2 -agonist detomidine is used for equine sedation with opioids such as methadone. We retrieved the data from two randomized, crossover studies where detomidine and methadone were given intravenously alone or combined as boli (STUDY 1) (Gozalo-Marcilla et al., 2017, Veterinary Anaesthesia and Analgesia, 2017, 44, 1116) or as 2-hr constant rate infusions (STUDY 2) (Gozalo-Marcilla et al., 2019, Equine Veterinary Journal, 51, 530). Plasma drug concentrations were measured with a validated tandem Mass Spectrometry assay. We used nonlinear mixed effect modelling and took pharmacokinetic (PK) data from both studies to fit simultaneously both drugs and explore their nonlinear kinetics. Two significant improvements over the classical mammillary two-compartment model were identified. First, the inclusion of an effect of detomidine plasma concentration on the elimination clearances (Cls) of both drugs improved the fit of detomidine (Objective Function Value [OFV]: -160) and methadone (OFV: -132) submodels. Second, a detomidine concentration-dependent reduction of distributional Cls of each drug further improved detomidine (OFV: -60) and methadone (OFV: -52) submodel fits. Using the PK data from both studies (a) helped exploring hypotheses on the nonlinearity of the elimination and distributional Cls and (b) allowed inclusion of dynamic effects of detomidine plasma concentration in the model which are compatible with the pharmacology of detomidine (vasoconstriction and reduction in cardiac output).
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Affiliation(s)
- Miguel Gozalo-Marcilla
- The Royal (Dick) School of Veterinary Studies and the Roslin Institute, The University of Edinburgh, Midlothian, UK
| | - Rodrigo Moreira da Silva
- Núcleo de Pesquisas em Produtos Naturais e Sintéticos (NPPNS), School of Pharmaceutical Sciences, University of São Paulo (USP), Ribeirão Preto, Brazil
| | | | | | - Mariana Werneck Fonseca
- São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu, Brazil
| | - Norberto Peporine Lopes
- Núcleo de Pesquisas em Produtos Naturais e Sintéticos (NPPNS), School of Pharmaceutical Sciences, University of São Paulo (USP), Ribeirão Preto, Brazil
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Sedative effect of intramuscular medetomidine with and without vatinoxan (MK-467), and its reversal with atipamezole in sheep. Vet Anaesth Analg 2018; 45:788-793. [DOI: 10.1016/j.vaa.2018.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/12/2018] [Accepted: 06/14/2018] [Indexed: 11/22/2022]
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Adam M, Raekallio MR, Keskitalo T, Honkavaara JM, Scheinin M, Kajula M, Mölsä S, Vainio OM. The impact of MK-467 on plasma drug concentrations, sedation and cardiopulmonary changes in sheep treated with intramuscular medetomidine and atipamezole for reversal. J Vet Pharmacol Ther 2018; 41:447-456. [DOI: 10.1111/jvp.12486] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/21/2017] [Indexed: 11/28/2022]
Affiliation(s)
- M. Adam
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
- Pharmacology Department; Faculty of Veterinary Medicine; Beni-Suef University; Beni-Suef Egypt
| | - M. R. Raekallio
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
| | - T. Keskitalo
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
| | - J. M. Honkavaara
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
| | - M. Scheinin
- Department of Pharmacology; Drug Development and Therapeutics; University of Turku; Turku Finland
- Unit of Clinical Pharmacology; Turku University Hospital; Turku Finland
| | | | - S. Mölsä
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
| | - O. M. Vainio
- Department of Equine and Small Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Helsinki Finland
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Bennett RC, Salla KM, Raekallio MR, Scheinin M, Vainio OM. Effects of the α2-adrenoceptor agonist medetomidine on the distribution and clearance of alfaxalone during coadministration by constant rate infusion in dogs. Am J Vet Res 2017; 78:956-964. [DOI: 10.2460/ajvr.78.8.956] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Schmitz S, Tacke S, Guth B, Henke J. Repeated anaesthesia with isoflurane and medetomidine-midazolam-fentanyl in guinea pigs and its influence on physiological parameters. PLoS One 2017; 12:e0174423. [PMID: 28328950 PMCID: PMC5362232 DOI: 10.1371/journal.pone.0174423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 03/08/2017] [Indexed: 12/17/2022] Open
Abstract
Repeated anaesthesia may be required in experimental protocols and in daily veterinary practice, but anaesthesia is known to alter physiological parameters in GPs (Cavia porcellus, GPs). This study investigated the effects of repeated anaesthesia with either medetomidine-midazolam-fentanyl (MMF) or isoflurane (Iso) on physiological parameters in the GP. Twelve GPs were repeatedly administered with MMF or Iso in two anaesthesia sets. One set consisted of six 40-min anaesthesias, performed over 3 weeks (2 per week); the anaesthetic used first was randomized. Prior to Iso anaesthesia, atropine was injected. MMF anaesthesia was antagonized with AFN (atipamezole-flumazenil-naloxone). Abdominally implanted radio-telemetry devices recorded the mean arterial blood pressure (MAP), heart rate (HR) and core body temperature continuously. Additionally, respiratory rate, blood glucose and body weight were assessed. An operable state could be achieved and maintained for 40 min in all GPs. During the surgical tolerance with MMF, the GPs showed a large MAP range between the individuals. In the MMF wake- up phase, the time was shortened until the righting reflex (RR) returned and that occurred at lower MAP and HR values. Repeated Iso anaesthesia led to an increasing HR during induction (anaesthesias 2–6), non-surgical tolerance (anaesthesias 3–6) and surgical tolerance (anaesthesias 4, 6). Both anaesthetics may be used repeatedly, as repeating the anaesthesias resulted in only slightly different physiological parameters, compared to those seen with single anaesthesias. The regular atropine premedication induced HR increases and repeated MMF anaesthesia resulted in a metabolism increase which led to the faster return of RR. Nevertheless, Iso’s anaesthesia effects of strong respiratory depression and severe hypotension remained. Based on this increased anaesthesia risk with Iso, MMF anaesthesia is preferable for repeated use in GPs.
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Affiliation(s)
- Sabrina Schmitz
- Department of Nonclinical Drug Safety, Biological Laboratory Service, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
- * E-mail:
| | - Sabine Tacke
- Department of Veterinary Clinical Sciences, Clinic for Small Animal-Surgery, Justus-Liebig-University, Giessen, Germany
| | - Brian Guth
- Department of Drug Discovery Support, General Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
- DST/NWU Preclinical Drug Development Platform, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Julia Henke
- Department of Nonclinical Drug Safety, Biological Laboratory Service, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
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de Vries A, Pakkanen SAE, Raekallio MR, Ekiri A, Scheinin M, Taylor PM, Vainio OM. Clinical effects and pharmacokinetic variables of romifidine and the peripheral α 2 ‐adrenoceptor antagonist MK‐467 in horses. Vet Anaesth Analg 2016; 43:599-610. [DOI: 10.1111/vaa.12354] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/24/2015] [Indexed: 11/29/2022]
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Bennett RC, Salla KM, Raekallio MR, Hänninen L, Rinne VM, Scheinin M, Vainio OM. Effects of MK-467 on the antinociceptive and sedative actions and pharmacokinetics of medetomidine in dogs. J Vet Pharmacol Ther 2016; 39:336-43. [DOI: 10.1111/jvp.12292] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 12/03/2015] [Indexed: 11/29/2022]
Affiliation(s)
- R. C. Bennett
- University Veterinary Hospital; UCD; Dublin Ireland
- Department of Equine and Small Animal Medicine; University of Helsinki; Helsinki Finland
| | - K. M. Salla
- Department of Equine and Small Animal Medicine; University of Helsinki; Helsinki Finland
| | - M. R. Raekallio
- Department of Equine and Small Animal Medicine; University of Helsinki; Helsinki Finland
| | - L. Hänninen
- Department of Production Animal Medicine; University of Helsinki; Helsinki Finland
| | - V. M. Rinne
- Department of Pharmacology; Drug Development and Therapeutics; University of Turku and Unit of Clinical Pharmacology; Turku University Hospital; Turku Finland
| | - M. Scheinin
- Department of Pharmacology; Drug Development and Therapeutics; University of Turku and Unit of Clinical Pharmacology; Turku University Hospital; Turku Finland
| | - O. M. Vainio
- Department of Equine and Small Animal Medicine; University of Helsinki; Helsinki Finland
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15
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Monteiro ER, Coelho K, Bressan TF, Simões CR, Monteiro BS. Effects of acepromazine-morphine and acepromazine-methadone premedication on the minimum alveolar concentration of isoflurane in dogs. Vet Anaesth Analg 2016; 43:27-34. [DOI: 10.1111/vaa.12265] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/13/2015] [Indexed: 12/01/2022]
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16
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Pypendop BH, Ilkiw JE. Pharmacokinetics of dexmedetomidine after intravenous administration of a bolus to cats. Am J Vet Res 2014; 75:441-5. [PMID: 24762015 DOI: 10.2460/ajvr.75.5.441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To characterize the pharmacokinetics of dexmedetomidine after IV administration of a bolus to conscious healthy cats. ANIMALS 5 healthy adult spayed female cats. PROCEDURES Dexmedetomidine was administered IV as a bolus at 3 doses (5, 20, or 50 μg/kg) on separate days in a random order. Blood samples were collected immediately before and at various times for 8 hours after drug administration. Plasma dexmedetomidine concentrations were determined with liquid chromatography-mass spectrometry. Compartment models were fitted to the concentration-time data by means of nonlinear regression. RESULTS A 2-compartment model best fit the concentration-time data after administration of 5 μg/kg, whereas a 3-compartment model best fit the data after administration of 20 and 50 μg/kg. The median volume of distribution at steady-state and terminal half-life were 371 mL/kg (range, 266 to 435 mL/kg) and 31.8 minutes (range, 30.3 to 39.7 minutes), respectively, after administration of 5 μg/kg; 545 mL/kg (range, 445 to 998 mL/kg) and 56.3 minutes (range, 39.3 to 68.9 minutes), respectively, after administration of 20 μg/kg; and 750 mL/kg (range, 514 to 938 mL/kg) and 75.3 minutes (range, 52.2 to 223.3 minutes), respectively, after administration of 50 μg/kg. CONCLUSIONS AND CLINICAL RELEVANCE The pharmacokinetics of dexmedetomidine was characterized by a small volume of distribution and moderate clearance and had minimal dose dependence within the range of doses evaluated. These data will help clinicians design dosing regimens once effective plasma concentrations are established.
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Affiliation(s)
- Bruno H Pypendop
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616
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17
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Vainionpää MH, Raekallio MR, Pakkanen SAE, Ranta-Panula V, Rinne VM, Scheinin M, Vainio OM. Plasma drug concentrations and clinical effects of a peripheral alpha-2-adrenoceptor antagonist, MK-467, in horses sedated with detomidine. Vet Anaesth Analg 2013; 40:257-64. [DOI: 10.1111/vaa.12012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 10/13/2012] [Indexed: 12/12/2022]
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18
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Crook KI, Early PJ, Messenger KM, Muñana KR, Gallagher R, Papich MG. The pharmacokinetics of cytarabine in dogs when administered via subcutaneous and continuous intravenous infusion routes. J Vet Pharmacol Ther 2012; 36:408-11. [DOI: 10.1111/jvp.12008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 07/31/2012] [Indexed: 11/26/2022]
Affiliation(s)
- K. I. Crook
- Department of Clinical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
| | - P. J. Early
- Department of Clinical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
| | - K. M. Messenger
- Department of Molecular and Biomedical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
| | - K. R. Muñana
- Department of Clinical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
| | - R. Gallagher
- Department of Clinical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
| | - M. G. Papich
- Department of Molecular and Biomedical Sciences; North Carolina State University College of Veterinary Medicine; Raleigh NC USA
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PYPENDOP BH, ESCOBAR A, SIAO KT, STANLEY SD, ILKIW JE. Effect of dexmedetomidine on its clearance: a pharmacokinetic model. J Vet Pharmacol Ther 2012; 36:89-91. [DOI: 10.1111/j.1365-2885.2012.01383.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Honkavaara J, Restitutti F, Raekallio M, Salla K, Kuusela E, Ranta-Panula V, Rinne V, Vainio O, Scheinin M. Influence of MK-467, a Peripherally Acting α2-Adrenoceptor Antagonist on the Disposition of Intravenous Dexmedetomidine in Dogs. Drug Metab Dispos 2011; 40:445-9. [DOI: 10.1124/dmd.111.042671] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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RANHEIM B, ARNEMO JM, STUEN S, HORSBERG TE. Medetomidine and atipamezole in sheep: disposition and clinical effects. J Vet Pharmacol Ther 2008. [DOI: 10.1111/j.1365-2885.2000.00282.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Lin GY, Robben JH, Murrell JC, Aspegrén J, McKusick BC, Hellebrekers LJ. Dexmedetomidine constant rate infusion for 24 hours during and after propofol or isoflurane anaesthesia in dogs. Vet Anaesth Analg 2008; 35:141-53. [DOI: 10.1111/j.1467-2995.2007.00365.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Theriault BR, Reed DA, Niekrasz MA. Reversible medetomidine/ketamine anesthesia in captive capuchin monkeys (Cebus apella). J Med Primatol 2008; 37 Suppl 1:74-81. [DOI: 10.1111/j.1600-0684.2007.00267.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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24
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Kästner SBR, Pakarinen SM, Ramela MP, Kutter APN, Boller J, Huhtinen MK. Comparative pharmacokinetics of medetomidine enantiomers in goats and sheep during sevoflurane anaesthesia. J Vet Pharmacol Ther 2006; 29:63-6. [PMID: 16420304 DOI: 10.1111/j.1365-2885.2006.00701.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S B R Kästner
- Equine Clinic, Anaesthesia Section, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
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Lapiz MDS, Morilak DA. Noradrenergic modulation of cognitive function in rat medial prefrontal cortex as measured by attentional set shifting capability. Neuroscience 2006; 137:1039-49. [PMID: 16298081 DOI: 10.1016/j.neuroscience.2005.09.031] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Revised: 09/07/2005] [Accepted: 09/24/2005] [Indexed: 11/20/2022]
Abstract
The brain noradrenergic system is thought to facilitate neuronal processes that promote behavioral activation, alertness, and attention. One region in which norepinephrine may exert such effects is the medial prefrontal cortex, which has been implicated in many cognitive functions including arousal, attention, motivation, working memory, response inhibition, and behavioral flexibility. The present study addressed the modulatory influence of noradrenergic neurotransmission in medial prefrontal cortex on cognitive function in rats, as measured by performance in an attentional set shifting task. In experiment 1, we tested effects of increasing and decreasing brain noradrenergic neurotransmission by systemic administration of the alpha2-adrenergic autoreceptor antagonist and agonist drugs, atipamezole and clonidine, respectively. Atipamezole pretreatment significantly improved performance on the stages of the attentional task requiring an extradimensional shift in attention, and those involving stimulus reversals, whereas clonidine had no effect at any stage. In experiment 2, we then tested effects of microinjecting alpha1- or beta-adrenergic receptor antagonists into medial prefrontal cortex on the enhancement of performance on the extradimensional task produced by atipamezole. The atipamezole-induced enhancement of performance on the extradimensional set shifting task was blocked by alpha1-, but not beta-adrenergic receptor antagonists in medial prefrontal cortex. Neither antagonist alone had any effect on extradimensional set shift performance in the absence of atipamezole-induced enhancement. These results indicate that elevating noradrenergic activity at alpha1-receptors in medial prefrontal cortex facilitates cognitive performance of rats in an attentional set-shifting task, which may contribute to the role of norepinephrine in behavioral state changes such as arousal, or to the beneficial cognitive effects of psychotherapeutic drugs that target noradrenergic neurotransmission.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Attention/drug effects
- Attention/physiology
- Clonidine/pharmacology
- Cognition/drug effects
- Cognition/physiology
- Data Interpretation, Statistical
- Excitatory Postsynaptic Potentials/drug effects
- Imidazoles/pharmacology
- Male
- Memory, Short-Term/drug effects
- Microinjections
- Norepinephrine/physiology
- Prefrontal Cortex/physiology
- Psychomotor Performance/drug effects
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/physiology
- Synaptic Transmission/drug effects
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Affiliation(s)
- M D S Lapiz
- Department of Pharmacology and Center for Biomedical Neuroscience, MC 7764, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
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26
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Ryeng KA, Arnemo JM, Larsen S. Determination of optimal immobilizing doses of a medetomidine hydrochloride and ketamine hydrochloride combination in captive reindeer. Am J Vet Res 2001; 62:119-26. [PMID: 11197548 DOI: 10.2460/ajvr.2001.62.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To establish optimal immobilizing doses of medetomidine hydrochloride (MED) with ketamine hydrochloride (KET) for hand- and dart-administered injections in captive reindeer. ANIMALS 12 healthy 6- to 9-month-old reindeer (Rangifer tarandus tarandus). Procedure An optimal dose was defined as a dose resulting in an induction time of 150 to 210 seconds, measured from the time of IM injection until recumbency. Initially, each stalled reindeer was immobilized by hand-administered injection. If the induction time was > 210 seconds, the dose was doubled for the next immobilization procedure. If it was < 150 seconds, the dose was halved for the next immobilization procedure. This iteration procedure was continued for each reindeer until an optimal dose was found. Later the reindeer was placed in a paddock and darted with its optimal dose as determined by hand-administered injection. Adjusting to a linear relationship between dose and induction time, optimal darting doses for each reindeer were predicted and later verified. RESULTS The established mean optimal hand- and dart-administered doses were 0.10 mg of MED/kg of body mass with 0.50 mg of KET/kg, and 0.15 mg of MED/kg with 0.75 mg of KET/kg, producing mean induction times of 171 seconds and 215 seconds, respectively. The mean induction time after darting was 5 seconds greater than the upper limit of the predefined time interval. CONCLUSIONS AND CLINICAL RELEVANCE The higher dose requirement of MED-KET administration outdoors, compared with indoors, was explained by factors inherent in the darting technique and the different confinements. The iteration and the prediction methods seem applicable for determination of optimal doses of MED-KET in reindeer. The iteration and the prediction procedures may be used to reduce the number of experimental animals in dose-response studies in other species.
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Affiliation(s)
- K A Ryeng
- Norwegian School of Veterinary Science, Department of Arctic Veterinary Medicine, Tromsø
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27
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Ranheim B, Arnemo JM, Stuen S, Horsberg TE. Medetomidine and atipamezole in sheep: disposition and clinical effects. J Vet Pharmacol Ther 2000; 23:401-4. [PMID: 11168919 DOI: 10.1046/j.1365-2885.2000.00282.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- B Ranheim
- Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway.
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28
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Soveri T, Sankari S, Salonen JS, Nieminen M. Effects of immobilization with medetomidine and reversal with atipamezole on blood chemistry of semi-domesticated reindeer (Rangifer tarandus tarandus L.) in autumn and late winter. Acta Vet Scand 2000. [PMID: 10918903 DOI: 10.1186/bf03547013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Blood chemistry was studied in 8 adult female reindeer, of which 5 were pregnant. Half of them received only medetomidine (150 micrograms/kg i.m.) and half of them medetomidine and atipamezole (750 micrograms/kg) in March. Three weeks later the drug regimens were reversed. The same procedure was carried out during the next September and October. Seasonal differences in pretreatment values could be seen in serum urea, phosphorous, and cholesterol, with the highest concentrations during the autumn; and creatinine, ASAT, ALAT, and CK values, which were higher in the non-pregnant reindeer in late winter. Their low-protein and low-energy diet during the winter explains most of the differences. Increased enzyme activities in serum indicate decreased membrane stability of certain organs in late winter, possibly due to nutritional deficiencies. Treatment effects could be seen in several parameters. The increase in blood glucose and decrease in serum FFA were most probably due to alpha 2-adrenoceptor activation, which inhibits insulin release and lipolysis. These effects were partly or totally inhibited after treatment with the antagonist atipamezole. The earlier increase in serum CK and ASAT activities in those receiving atipamezole can be explained by increased tissue perfusion due to atipamezole itself and the fact that these animals stood up and began to move much earlier than did those which received medetomidine only. A significant decrease in serum Na+, K+, Cl-, Pi, cholesterol, total Ca, and total protein concentration observed during the first 10 to 40 min of the medetomidine sedation could be explained by possible haemodilution and diuresis. More effective metabolism of medetomidine in autumn could explain the shorter recovery times of reindeer receiving only medetomidine and most of the differences in treatment effects between the seasons: faster increase in protein and cholesterol concentrations after the decrease, and the antagonistic effect of atipamezole on glucose and Pi changes in autumn. Based on these results, medetomidine seems to be a good sedation agent for reindeer both in autumn and in late winter; the effects of medetomidine can be rather effectively antagonized by atipamezole.
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29
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Kuusela E, Raekallio M, Anttila M, Falck I, Mölsä S, Vainio O. Clinical effects and pharmacokinetics of medetomidine and its enantiomers in dogs. J Vet Pharmacol Ther 2000; 23:15-20. [PMID: 10747239 DOI: 10.1046/j.1365-2885.2000.00245.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The clinical effects and pharmacokinetics of medetomidine (MED) and its enanti-omers, dexmedetomidine (DEX) and levomedetomidine (LEVO) were compared in a group of six beagle dogs. The dogs received intravenously (i.v.) a bolus of MED (40 microg/kg), DEX (20 and 10 microg/kg), LEVO (20 and 10 microg/kg), and saline placebo in a blinded, randomized block study in six separate sessions. Sedation and analgesia were scored subjectively, and the dogs were monitored for heart rate, ECG lead II, direct blood pressure, respiratory rate, arterial blood gases, and rectal body temperature. Blood samples for drug analysis were taken. Peak sedative and analgesic effects were observed at mean (+/- SD) plasma levels of 18.5 +/- 4.7 ng/mL for MED40, 14.0 +/- 4.5 ng/mL for DEX20, and 5.5 +/- 1.3 ng/mL for DEX10. The overall level of sedation and cardiorespiratory effects did not differ between MED40, DEX20 and DEX10 during the first hour, apparently due to a ceiling effect. However, the analgesic effect of DEX20 lasted longer than the effect of the corresponding dose of racemic medetomidine, suggesting greater potency for dexmedetomidine in dogs. Levomedetomidine had no effect on cardio-vascular parameters and caused no apparent sedation or analgesia. The pharmacokinetics of dexmedetomidine and racemic medetomidine were similar, but clearance of levomedetomidine was more rapid (4.07 +/- 0.69 L/h/kg for LEVO20 and 3.52 +/- 1.03 for LEVO10) than of the other drugs (1.26 +/- 0.44 L/h/kg for MED40, 1.24 +/- 0.48 for DEX20, and 0.97 +/- 0.33 for DEX10).
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Affiliation(s)
- E Kuusela
- Faculty of Veterinary Medicine, Department of Clinical Sciences, Hämeentie 57, FIN-00014 University of Helsinki, Finland
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30
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Ranheim B, Arnemo JM, Ryeng KA, Søli NE, Horsberg TE. A pharmacokinetic study including some relevant clinical effect of medetomidine and atipamezole in lactating dairy cows. J Vet Pharmacol Ther 1999; 22:368-73. [PMID: 10651465 DOI: 10.1046/j.1365-2885.1999.00231.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Medetomidine is the most potent and selective alpha2-agonist used in veterinary medicine and its effects can be antagonized by the alpha2-antagonist atipamezole. The pharmacokinetics of medetomidine and atipamezole were studied in a cross-over trial in eight lactating dairy cows. The animals were injected intravenously (i.v.) with medetomidine (40 microg/kg) followed by atipamezole i.v. (200 microg/kg) or saline i.v. after 60 min. Drug concentrations in plasma were measured by HPLC. After the injection of atipamezole, the concentration of medetomidine in plasma increased slightly, the mean increment being 2.7 ng/mL and the mean duration 12.1 min. However, atipamezole did not alter the pharmacokinetics of medetomidine. It is likely that the increase in medetomidine concentration is caused by displacement of medetomidine by atipamezole in highly perfused tissues. The volume of distribution at steady state (Vss) for medetomidine followed by saline and medetomidine followed by atipamezole was 1.21 and 1.32 L/kg, respectively, whereas the total clearance (Cl) values were 24.2 and 25.8 mL/min x kg. Vss and Cl values for atipamezole were 1.77 mL/kg and 48.1 mL/min x kg, respectively. Clinically, medetomidine significantly reduced heart rate and increased rectal temperature for 45 min. Atipamezole reversed the sedative effects of medetomidine. However, all the animals, except one, relapsed into sedation at an average of 80 min after injection of the antagonist.
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Affiliation(s)
- B Ranheim
- Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, Oslo.
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31
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Horsberg T, Burka J, Tasker R. Actions and pharmacokinetic properties of the α2-adrenergic agents, medetomidine and atipamezole, in rainbow trout (Oncorhynchus mykiss). ACTA ACUST UNITED AC 1999. [DOI: 10.1111/j.1467-2995.1999.tb00179.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Grimm KA, Thurmon JC, Olson WA, Tranquilli WJ, Benson GJ. The pharmacodynamics of thiopental, medetomidine, butorphanol and atropine in beagle dogs. J Vet Pharmacol Ther 1998; 21:133-7. [PMID: 9597651 DOI: 10.1046/j.1365-2885.1998.00119.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study evaluated the quality of anaesthesia and some of the haemodynamic effects induced by a combination of thiopental, medetomidine, butorphanol and atropine in healthy beagle dogs (n = 12). Following premedication with atropine (ATR, 0.022 mg/kg intravenously (i.v.)) and butorphanol (BUT, 0.22 mg/kg i.v.), medetomidine (MED, 22 micrograms/kg intramuscularly (i.m.)) was administered followed in 5 min by thiopental (THIO, 2.2 mg/kg i.v.). Heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MBP) were monitored continuously with an ECG and direct arterial blood pressure monitor. Atipamezole (ATI, 110 micrograms/kg i.v.) was administered to half of the dogs (n = 6) following surgery to evaluate the speed and quality of arousal from anaesthesia. Anaesthesia was characterized by excellent muscle relaxation, analgesia and absence of purposeful movement in response to surgical castration. Arousal following antagonism of medetomidine was significantly faster (P < 0.05) than in unantagonized dogs. Recoveries were smooth but recovery times following atipamezole administration were highly variable among dogs (sternal time range 6-38 min, standing time range 9-56 min). Medetomidine caused a significant (P < 0.05) increase in SBP, DBP and MBP. Atropine prevented the medetomidine induced bradycardia. In conclusion, this combination provided adequate surgical anaesthesia in healthy beagle dogs. At the dosages used in this study, it seems prudent that this combination should be reserved for dogs free of myocardial disease.
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Affiliation(s)
- K A Grimm
- University of Illinois College of Veterinary Medicine, Department of Veterinary Clinical Medicine, Urbana 61801, USA
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