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Huang X, Hyuga S, Amakura Y, Hyuga M, Uchiyama N, Hakamatsuka T, Goda Y, Odaguchi H, Hanawa T, Kobayashi Y. Overlooked switch from transient sedation to sustained excitement in the Biphasic effects of Ephedra Herb extract administered orally to mice. JOURNAL OF ETHNOPHARMACOLOGY 2023; 301:115827. [PMID: 36240977 DOI: 10.1016/j.jep.2022.115827] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/29/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE In our previous study, we reported that Ephedra Herb extract (EHE) increased the locomotor activity of mice in the open-field test and reduced the immobility time in the forced swim test. Ephedrine alkaloids (EAs) are thought to be responsible for the adverse effects of Ephedra Herb. However, there are no reports to verify that the adverse effects of Ephedra Herb are caused by the amount of EAs in the herb. Therefore, we investigated whether these adverse effects of EHE are caused by the amounts of ephedrine (Eph) and pseudoephedrine (Pse) in the herbal extract. In a preliminary study of the time course analysis of the open field test, we newly observed that EHE evoked switching from transient sedation to sustained excitement. AIM OF THE STUDY We aimed to confirm whether EHE evokes switching from transient sedation to sustained excitement, investigate whether these actions of EHE are caused by the amount of ephedrine (Eph) and pseudoephedrine (Pse) in the herbal extract, and clarify the molecular mechanism of the transient sedative effect. MATERIALS AND METHODS The locomotor activity of mice was tested using the open-field test. The immobility times were measured using a forced swim test, and the motor dysfunction in mice was tested using the rotarod test. RESULTS EHE, Eph, and Pse induced transient motionlessness between 0 and 15 min after oral administration, however, they did not induce depression-like behavior and motor dysfunction in mice, suggesting that the motionlessness induced by EHE, Eph, or Pse resulted from sedation. The α2a adrenoceptor inhibitor, atipamezole, decreased their sedative effects. Thus, immediately after EHE administration, the transient sedative effect is mediated through the activation of the α2a adrenoreceptor by Eph and Pse. EHE and Eph increased total locomotor activity for 15-120 min after oral administration; however, Pse had no effect. Therefore, the slow-onset and sustained excitatory effects of EHE are mediated by Eph. CONCLUSIONS We discovered for the first time that EHE evokes diphasic action by switching from transient sedation to sustained excitement. The transient sedation was evoked by the Eph and Pse in the herbal extract via activation of the α2a adrenoceptor and the sustained excitement was caused by the Eph in the herbal extract.
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Affiliation(s)
- Xuedan Huang
- Department of Pharmacognosy, School of Pharmacy, Kitasato University, Tokyo, Japan; Oriental Medicine Research Center of Kitasato University, Tokyo, Japan.
| | - Sumiko Hyuga
- Oriental Medicine Research Center of Kitasato University, Tokyo, Japan.
| | - Yoshiaki Amakura
- Department of Pharmacognosy, College of Pharmaceutical Sciences, Matsuyama University, Ehime, Japan.
| | - Masashi Hyuga
- National Institute of Health Sciences, Kanagawa, Japan.
| | | | | | - Yukihiro Goda
- National Institute of Health Sciences, Kanagawa, Japan.
| | - Hiroshi Odaguchi
- Oriental Medicine Research Center of Kitasato University, Tokyo, Japan.
| | - Toshihiko Hanawa
- Oriental Medicine Research Center of Kitasato University, Tokyo, Japan.
| | - Yoshinori Kobayashi
- Department of Pharmacognosy, School of Pharmacy, Kitasato University, Tokyo, Japan; Oriental Medicine Research Center of Kitasato University, Tokyo, Japan.
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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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Abouelfetouh MM, Salah E, Ding M, Ding Y. Application of α 2 -adrenergic agonists combined with anesthetics and their implication in pulmonary intravascular macrophages-insulted pulmonary edema and hypoxemia in ruminants. J Vet Pharmacol Ther 2021; 44:478-502. [PMID: 33709435 DOI: 10.1111/jvp.12960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/08/2021] [Indexed: 11/29/2022]
Abstract
Alpha2 -adrenergic agonists have been implicated in the development of pulmonary edema (PE) and sustained hypoxemia that lead to life-threatening pulmonary distress in ruminants, especially with sensitive and compromised animals. Recently, there is limited understanding of exact mechanism underlying pulmonary alterations associated with α2 -adrenergic agonist administration. Ruminants have a rich population of pulmonary intravascular macrophages (PIMs) in the pulmonary circulation, which may be involved in the development of pulmonary alveolo-capillary barrier damage. Hence, the central thesis of this review is overviewing the literatures regarding the systemic use of α2 -adrenergic agonists in domestic ruminants, focusing on their pulmonary side effects, especially on the influence of PIMs on the lung. At this moment, further studies are needed to provide a clear emphasis and better understanding of the potential role of PIMs in the lung pathophysiology associated with α2 -adrenergic agonists. These preliminary studies would be potentially to develop future medications and intervention targets that may be helpful to alleviate or prevent the critical striking pulmonary effects, and thereby improving the safety of α2 -agonist application in ruminants.
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Affiliation(s)
- Mahmoud M Abouelfetouh
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Department of Surgery, Radiology and Anaesthesiology, Faculty of Veterinary Medicine, Benha University, Moshtohor, Toukh, Egypt
| | - Eman Salah
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, China.,Department of Pharmacology, Faculty of Veterinary Medicine, Benha University, Moshtohor, Toukh, Egypt
| | - Mingxing Ding
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yi Ding
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China
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4
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Clapham MO, Martin KL, Davis JL, Baynes RE, Lin Z, Vickroy TW, Riviere JE, Tell LA. Extralabel drug use in wildlife and game animals. J Am Vet Med Assoc 2020; 255:555-568. [PMID: 31429657 DOI: 10.2460/javma.255.5.555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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5
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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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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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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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8
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Cagnardi P, Villa R, Ravasio G, Lucatello L, Di Cesare F, Capolongo F, Boccardo A, Pravettoni D. Pharmacokinetics and sedative effects of dexmedetomidine in dairy calves. N Z Vet J 2016; 65:14-18. [DOI: 10.1080/00480169.2016.1237313] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- P Cagnardi
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Milan 20133, Italy
| | - R Villa
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Milan 20133, Italy
| | - G Ravasio
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan 20133, Italy
| | - L Lucatello
- Department of Comparative Biomedicine and Food Science, Università degli Studi di Padova, Legnaro (Padua) 35020, Italy
| | - F Di Cesare
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Milan 20133, Italy
| | - F Capolongo
- Department of Comparative Biomedicine and Food Science, Università degli Studi di Padova, Legnaro (Padua) 35020, Italy
| | - A Boccardo
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan 20133, Italy
| | - D Pravettoni
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan 20133, Italy
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9
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Hyndman TH, Musk GC, Murdoch FR, Maker GL, Whittem T. The bioavailability of medetomidine in eight sheep following oesophageal administration. Res Vet Sci 2015; 103:137-42. [PMID: 26679808 DOI: 10.1016/j.rvsc.2015.09.014] [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: 04/09/2015] [Revised: 07/08/2015] [Accepted: 09/20/2015] [Indexed: 11/17/2022]
Abstract
There is sound evidence that medetomidine is an effective analgesic for acute pain in sheep. In this study, 15 μg kg(-1) of medetomidine was administered intravenously, and into the oesophagus, in a cross-over study, using eight sheep. Following intravenous administration, medetomidine could be detected in the plasma of these sheep for 120-180 min but following oesophageal administration, medetomidine could not be detected in the plasma of any sheep at any of 17 time points over four days. It is suspected that this is due to high first pass metabolism in the liver. Consequently, we conclude that future studies investigating the use of analgesics in orally-administered osmotic pumps in sheep should consider higher doses of medetomidine (e.g. >100 μg kg(-1)), further investigations into the barriers of medetomidine bioavailability from the sheep gut, liver-bypass drug delivery systems, or other α2-adrenergic agonists (e.g. clonidine or xylazine).
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Affiliation(s)
- Timothy H Hyndman
- School of Veterinary and Life Sciences, Murdoch University, Perth, Australia.
| | - Gabrielle C Musk
- School of Veterinary and Life Sciences, Murdoch University, Perth, Australia
| | - Fraser R Murdoch
- School of Veterinary and Life Sciences, Murdoch University, Perth, Australia; Scottish Centre for Production Animal Health and Food Safety, School of Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Garth L Maker
- School of Veterinary and Life Sciences, Murdoch University, Perth, Australia
| | - Ted Whittem
- Translational Research and Clinical Trials (TRACTs) Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 250 Princes Highway, Werribee, Victoria, Australia
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10
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Knych HK, Stanley SD. Effects of three antagonists on selected pharmacodynamic effects of sublingually administered detomidine in the horse. Vet Anaesth Analg 2014; 41:36-47. [DOI: 10.1111/vaa.12081] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 12/10/2012] [Indexed: 11/29/2022]
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Singh GD, Kinjavdekar P, Amarpal, Aithal HP, Pawde AM, Zama MMS, Singh J, Tiwary R. Clinicophysiological and haemodynamic effects of fentanyl with xylazine, medetomidine and dexmedetomidine in isoflurane-anaesthetised water buffaloes (Bubalus bubalis). J S Afr Vet Assoc 2013; 84:E1-E11. [PMID: 23718913 DOI: 10.4102/jsava.v84i1.67] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/24/2012] [Accepted: 11/21/2012] [Indexed: 11/01/2022] Open
Abstract
The present study was undertaken to investigate the sedative, analgesic and clinical effects of xylazine, medetomidine and dexmedetomidine with fentanyl as pre-anaesthetics in water buffaloes and to compare the dose-sparing effect of xylazine, medetomidine and dexmedetomidine on thiopental for induction and isoflurane for maintenance of anaesthesia in water buffaloes. Six male water buffaloes randomly received intravenous fentanyl (5.0 µg/kg body weight) and xylazine (0.05 mg/kg body weight), fentanyl (5.0 µg/kg body weight) and medetomidine (2.5 µg/kg body weight), fentanyl (5.0 µg/kg body weight) and dexmedetomidine (5.0 µg/kg body weight) at weekly intervals in groups I1, I2 and I3, respectively. After 15 min, the animals were restrained in right lateral recumbency and anaesthesia was induced by 5% thiopental sodium administered intravenously. The intubated animal was connected to the large animal anaesthesia machine and isoflurane in 100% oxygen (5 L/min) was insufflated for 60 min. The treatments were compared by clinicophysiological, haematobiochemical and haemodynamic parameters. Fentanyl-medetomidine and fentanyl-dexmedetomidine produced more cardiovascular depression during the pre-anaesthetic period but less depression of cardio-respiratory dynamics in the post induction and maintenance period. Quicker recovery was recorded in I2 and I3 groups. A lower dose of thiopental was required in group I3 (4.33 mg/kg ± 0.66 mg/kg) than in groups I2 (4.41 mg/kg ± 0.98 mg/kg) and I1 (4.83 mg/kg ± 0.79 mg/kg). The dose of isoflurane was less in group I3 (45.50 mL ± 5.45 mL) than in group I1 and I2 (48.66 mL ± 5.10 mL and 48.00 mL ± 6.38 mL). Better anaesthesia was recorded with fentanyl-dexmedetomidine-thiopental-isoflurane (group I3) than with fentanyl-medetomidine-thiopental-isoflurane (group I2) and fentanyl-xylazine-thiopental-isoflurane (group I1). Fentanyl-medetomidine and fentanyl-dexmedetomidine were better pre-anaesthetic agents in comparison to fentanyl-xylazine for thiopental and isoflurane anaesthesia. Fentanyl-dexmedetomidine-thiopental-isoflurane and fentanyl-medetomidine-thiopental-isoflurane produced effective surgical anaesthesia and were found to be safe, as cardio-pulmonary functions were well preserved during maintenance anaesthesia with no deleterious effect on vital organ functions in water buffaloes.
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Affiliation(s)
- Gyan D Singh
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar-243122, Bareilly, India
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Yokota SI, Hikasa Y, Shimura I, Kusunose S. Effects of imidazoline and nonimidazoline alpha-adrenergic agents, including xylazine, medetomidine, yohimbine, tolazoline, and atipamezole, on aggregation of bovine and equine platelets. Am J Vet Res 2013; 74:395-402. [DOI: 10.2460/ajvr.74.3.395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Brøndum E, Hasenkam JM, Secher NH, Bertelsen MF, Grøndahl C, Petersen KK, Buhl R, Aalkjær C, Baandrup U, Nygaard H, Smerup M, Stegmann F, Sloth E, Østergaard KH, Nissen P, Runge M, Pitsillides K, Wang T. Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1058-65. [DOI: 10.1152/ajpregu.90804.2008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 ± 11 mmHg (mean ± SE), carotid flow was 0.7 ± 0.2 l/min, and carotid cross-sectional area was 0.85 ± 0.04 cm2. Central venous pressure (CVP) was 4 ± 2 mmHg, jugular flow was 0.7 ± 0.2 l/min, and jugular cross-sectional area was 0.14 ± 0.04 cm2 ( n = 4). Carotid arterial and jugular venous pressures at head level were 118 ± 9 and −7 ± 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 ± 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to −1 ± 2 mmHg ( P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 ± 0.6 cm2 ( P < 0.01), corresponding to accumulation of ∼1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.
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Affiliation(s)
| | - J. M. Hasenkam
- Institute of Clinical Medicine, Departments of CardioThoracic and Vascular Surgery, and
| | | | - M. F. Bertelsen
- Department of Large Animal Science, University of Copenhagen, and
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Copenhagen, Denmark
| | - C. Grøndahl
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Copenhagen, Denmark
| | | | - R. Buhl
- Department of Large Animal Science, University of Copenhagen, and
| | | | - U. Baandrup
- Institute of Pathology, Aarhus University Hospital, Aarhus, Denmark
- Vendsyssel Hospital, Hjørring, Denmark
| | - H. Nygaard
- Institute of Clinical Medicine, Departments of CardioThoracic and Vascular Surgery, and
- Engineering College of Aarhus, Aarhus, Denmark
| | - M. Smerup
- Institute of Clinical Medicine, Departments of CardioThoracic and Vascular Surgery, and
| | - F. Stegmann
- Department of Companion Animal Clinical Studies, University of Pretoria, Pretoria, South Africa; and
| | - E. Sloth
- Institute of Clinical Medicine, Departments of CardioThoracic and Vascular Surgery, and
| | | | - P. Nissen
- Department of Anesthesiology, Rigshospitalet,
| | - M. Runge
- Department of Anesthesiology, Rigshospitalet,
| | | | - T. Wang
- Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus, Denmark
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RANHEIM B, HORSBERG TE, SØLI NE, RYENG KA, ARNEMO JM. The effects of medetomidine and its reversal with atipamezole on plasma glucose, cortisol and noradrenaline in cattle and sheep. J Vet Pharmacol Ther 2008. [DOI: 10.1111/j.1365-2885.2000.00291.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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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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16
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Rioja E, Kerr CL, Enouri SS, McDonell WN. Sedative and cardiopulmonary effects of medetomidine hydrochloride and xylazine hydrochloride and their reversal with atipamezole hydrochloride in calves. Am J Vet Res 2008; 69:319-29. [DOI: 10.2460/ajvr.69.3.319] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
OBJECTIVE To review the use and adverse effects of alpha(2)-agonists in sheep. STUDY DESIGN Literature review. MATERIAL AND METHODS 'Pubmed' of the United States National Library of Medicine and 'Veterinary Science' of CAB International were searched for references relating sheep to alpha(2)-agonists. The bibliographies of retrieved articles were further scrutinized for pertinent references, and relevant articles were selected manually. RESULTS Reports on the use of clonidine, xylazine, detomidine, romifidine, medetomidine and dexmedetomidine, MPV-2426 and ST-91 in sheep were found in the literature. Most of the studies described xylazine followed by medetomidine and clonidine. The literature on detomidine and romifidine in sheep was sparse. Reports included pharmacokinetic studies, evaluation of sedative, analgesic, and anaesthetic techniques with or without cardiovascular effects, and experimental investigations of adverse effects (mainly hypoxaemia) including the mechanisms of pulmonary oedema and impaired oxygenation after alpha(2)-agonist administration. CONCLUSIONS A(2)-agonists are potent and effective analgesics in sheep. In combination with ketamine, they are frequently used for the induction and maintenance of anaesthesia, in this case analgesia is satisfactory. The degree of hypoxaemia which occurs with all commercially available alpha(2)-agonists is highly variable and depends on individual or breed-related factors; the most severe reactions occur after intravenous (IV) injection and during general anaesthesia. Clinical relevance Subclinical respiratory disease is common in sheep. Rapid IV injection of alpha(2)-agonists without supplementary oxygen should be avoided whenever hypoxaemia may be critical.
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Affiliation(s)
- Sabine B R Kästner
- Equine Clinic, Section of Veterinary Anaesthesia, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
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18
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Carroll GL, Hartsfield SM, Champney TH, Geller SC, Martinez EA, Haley EL. Effect of medetomidine and its antagonism with atipamezole on stress-related hormones, metabolites, physiologic responses, sedation, and mechanical threshold in goats. Vet Anaesth Analg 2005; 32:147-57. [PMID: 15877661 DOI: 10.1111/j.1467-2995.2005.00187.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To evaluate the effects of medetomidine and its antagonism with atipamezole in goats. STUDY DESIGN Prospective randomized crossover study with 1 week between treatments. ANIMALS Six healthy 3-year-old neutered goats (three male and three female) weighing 39.1-90.9 kg (60.0 +/- 18 kg, mean +/- SD). METHODS Goats were given medetomidine (20 microg kg(-1), IV) followed, 25 minutes later, by either atipamezole (100 microg kg(-1), IV) or saline. Heart and respiratory rate, rectal temperature, indirect blood pressure, and mechanical threshold were measured, and sedation and posture were scored and blood samples obtained to measure epinephrine, norepinephrine, free fatty acids, glucose, and cortisol concentrations at baseline (immediately before medetomidine), 5 and 25 minutes after medetomidine administration, and at 5, 30, 60, and 120 minutes after the administration of antagonist or saline. Parametric and nonparametric tests were used to evaluate data; p < 0.05 was considered significant. RESULTS Medetomidine decreased body temperature, heart rate, and respiratory rate and increased mean arterial blood pressure, cortisol, and glucose. Recumbency occurred 89 +/- 50 seconds after medetomidine administration. All goats were standing 86 +/- 24 seconds after atipamezole administration whereas all goats administered saline were sedate and recumbent at 2 hours. Tolerance to compression of the withers and metacarpus increased with medetomidine. From 5 to 120 minutes after saline or atipamezole administration, there were differences in body temperature, glucose, and cortisol but none in heart rate or blood pressure. Three of the six goats receiving saline developed bloat; five of six urinated. After atipamezole, four of six goats developed piloerection and all goats were agitated and vocalized. CONCLUSION At the doses used, atipamezole antagonized the effects of medetomidine on recumbency, sedation, mechanical threshold, and the increase in glucose. Atipamezole increased the rate of return of cortisol toward baseline, and prevented further decline in rectal body temperature. CLINICAL RELEVANCE Atipamezole may be used to antagonize some, but not all effects of medetomidine.
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Affiliation(s)
- Gwendolyn L Carroll
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, 77843, USA.
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Abstract
The article explores the choices and considerations pertinent to the selection of an anesthetic protocol for use in cattle. When the veterinarian is presented with the opportunity to provide anesthesia for surgical or diagnostic procedures, the options include use of local anesthetics, sedative-tranquilizer and analgesic combinations, or general anesthetic techniques. Informed decisions regarding selection of an anesthetic technique or protocol are made possible with understanding of the perianesthetic considerations commonly recognized for cattle.
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Affiliation(s)
- Stephen A Greene
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6610, USA.
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20
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Lee I, Yamagishi N, Oboshi K, Yamada H. Antagonistic effects of intravenous or epidural atipamezole on xylazine-induced dorsolumbar epidural analgesia in cattle. Vet J 2003; 166:194-7. [PMID: 12902186 DOI: 10.1016/s1090-0233(03)00026-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study was performed to clarify the antagonistic actions of intravenous or epidural atipamezole on the sedative and analgesic effects of xylazine administered between the epidural fat and dura mater through the first interlumbar space in cattle. Cattle received 5 mL of a solution containing 0.05 mg x kg(-1) xylazine in 0.9% saline. Thirty minutes later, 5 mL of 0.9% saline was administered through the same needle (treatment 1) (XSE). In treatments 2 (XAE) and 3 (XAV), 5 mL of a solution containing 0.025 mg x kg(-1) atipamezole in 0.9% saline was administered epidurally or intravenously, respectively. Sedation and analgesia were similar in all three treatment groups and could be reversed by atipamezole given by either route. In the XAV treatment, the flank area relapsed into analgesia 25+/-5.8 min following reversal of the analgesic effect, and was maintained for 112.5+/-63.8 min. The present study confirmed that the sedative and analgesic effects of xylazine are completely reversed by atipamezole and can be influenced by the epidural fat in cattle. Furthermore, it seems probable that analgesia following epidural administration of xylazine is mediated by alpha(2)-adrenergic receptors, not by a local anaesthetic effect.
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Affiliation(s)
- I Lee
- Department of Clinical Veterinary Science, School of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan.
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21
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Kästner SBR, Wapf P, Feige K, Demuth D, Bettschart- Wolfensberger R, Akens MK, Huhtinen M. Pharmacokinetics and sedative effects of intramuscular medetomidine in domestic sheep. J Vet Pharmacol Ther 2003; 26:271-6. [PMID: 12887609 DOI: 10.1046/j.1365-2885.2003.00492.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Intramuscular (i.m.) administration of medetomidine (MED) may avoid the severe pressor effects caused by peripheral actions of MED associated with intravenous (i.v.) dosing. The purpose of this study was to determine the pharmacokinetics, the time course of sedation and occurence of hypoxaemia after i.m. administration of MED in domestic sheep. The MED was injected i.m. at a dose of 30 micro g/kg in nine domestic sheep. Blood was sampled at 0, 5, 10, 20, 30, 40, 60, 120, 180, 240, 360 and 600 min after MED. Sedation was assessed and arterial blood samples were taken before and 35 min after MED application. Mean (SD) pharmacokinetic parameters of i.m. MED were: absorption half-life: 13.2 (7.5) min; terminal half-life: 32.7 (14.9) min; time to peak concentration: 29.2 (8.9) min; peak concentration: 4.98 (1.89) ng/mL; volume of distribution: 3.9 (2.4) l/kg; total body clearance: 81.0 (21.5) mL/(min kg). Peak sedation occurred between 30 and 40 min after injection of MED. The degree of sedation correlated with individual plasma concentrations (rS: 0.926). One animal became hypoxaemic (PaO2 = 54.1 mmHg).
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Affiliation(s)
- S B R Kästner
- Equine Clinic, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse, Zurich, Switzerland.
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22
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Ranheim B, Horsberg TE, Søli NE, Ryeng KA, Arnemo JM. The effects of medetomidine and its reversal with atipamezole on plasma glucose, cortisol and noradrenaline in cattle and sheep. J Vet Pharmacol Ther 2000; 23:379-87. [PMID: 11168916 DOI: 10.1046/j.1365-2885.2000.00291.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the present study, we report the effect of medetomidine followed by atipamezole on plasma glucose, cortisol and noradrenaline in calves, cows and sheep. Eight calves, eight lactating dairy cows and eight adult female sheep were included in a crossover trial. The animals were injected i.v. with medetomidine (40 microg/kg), followed 60 min later by atipamezole i.v. (200 microg/kg) or saline. The wash-out period between experiments was 1 or 2 weeks. In every animal, medetomidine induced a marked hyperglycaemia, which was reversed by atipamezole. Cortisol levels increased significantly in cows and sheep, reaching levels 4-8-fold higher than the baseline levels 25-45 min after injection of medetomidine. Atipamezole did not affect the cortisol levels, except in sheep where an increase was observed. Plasma levels of noradrenaline decreased in cows and sheep after medetomidine injection, reflecting the inhibition of sympathetic activity by the drug. After injection of the antagonist, there was a large increase in noradrenaline levels. In conclusion, a high dose of medetomidine does not seem to reduce the overall endocrine stress response in cattle and sheep, which has previously been reported in other species.
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Affiliation(s)
- B Ranheim
- Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, P.O. Box 8146 Dep., NO-0033 Oslo, Norway.
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23
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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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