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Guo Y, Mao S, Zhou Z. Effects of intramuscular alfaxalone and dexmedetomidine alone and combined on ocular, electroretinographic, and cardiorespiratory parameters in normal cats. Front Vet Sci 2024; 11:1407928. [PMID: 39021405 PMCID: PMC11251925 DOI: 10.3389/fvets.2024.1407928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 05/17/2024] [Indexed: 07/20/2024] Open
Abstract
Background This study aimed to determine the effects of intramuscular (IM) administration of alfaxalone with or without dexmedetomidine on short electroretinography (ERG), ocular parameters and cardiorespiratory in healthy cats. Methods Eight healthy female spayed cats were treated with three sedation protocols: IM administration of 5 μg/kg dexmedetomidine (DEX), 5 mg/kg alfaxalone (ALF), and 5 μg/kg dexmedetomidine plus 5 mg/kg alfaxalone (DEX + ALF). The washout period after each treatment was 2 weeks. Physiological parameters, time metrics, intraocular pressure (IOP), Schirmer tear test 1 (STT-1) and a short ERG protocol were recorded. For age data, weight data, time metrics and ERG data, one-way ANOVA with Bonferroni posterior comparisons were performed. For physiological parameters, IOP and STT-1 data, two-way repeated measures ANOVA with Bonferroni posterior comparisons were performed. Statistical significance was set at a p-value <0.05. Results IOPs were increased in all three groups compared to baseline and showed no significant differences among three groups at any time point. STT-1 values were decreased significantly during the process. Significant differences were noticed between a-wave amplitude in the dark-adapted response between DEX and ALF, and a-wave amplitude in light-adapted response between ALF and DEX + ALF. Conclusion This study demonstrates the feasibility of three sedation protocols for short ERG recording in cats. All these treatments resulted in increased IOP values and reduced STT-1 values. But baseline data of ERG was not obtained as a blank control in cats.
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Affiliation(s)
| | | | - Zhenlei Zhou
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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Chang S, Legg-St. Pierre CB, Ambros B. Comparison of Sedative Effects of Alfaxalone-Ketamine and Alfaxalone-Midazolam Administered Intramuscularly in Chickens. J Avian Med Surg 2022; 36:21-27. [DOI: 10.1647/20-00111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Navarro KL, Huss M, Smith JC, Sharp P, Marx JO, Pacharinsak C. Mouse Anesthesia: The Art and Science. ILAR J 2021; 62:238-273. [PMID: 34180990 PMCID: PMC9236661 DOI: 10.1093/ilar/ilab016] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/04/2021] [Accepted: 12/01/2020] [Indexed: 12/15/2022] Open
Abstract
There is an art and science to performing mouse anesthesia, which is a significant component to animal research. Frequently, anesthesia is one vital step of many over the course of a research project spanning weeks, months, or beyond. It is critical to perform anesthesia according to the approved research protocol using appropriately handled and administered pharmaceutical-grade compounds whenever possible. Sufficient documentation of the anesthetic event and procedure should also be performed to meet the legal, ethical, and research reproducibility obligations. However, this regulatory and documentation process may lead to the use of a few possibly oversimplified anesthetic protocols used for mouse procedures and anesthesia. Although a frequently used anesthetic protocol may work perfectly for each mouse anesthetized, sometimes unexpected complications will arise, and quick adjustments to the anesthetic depth and support provided will be required. As an old saying goes, anesthesia is 99% boredom and 1% sheer terror. The purpose of this review article is to discuss the science of mouse anesthesia together with the art of applying these anesthetic techniques to provide readers with the knowledge needed for successful anesthetic procedures. The authors include experiences in mouse inhalant and injectable anesthesia, peri-anesthetic monitoring, specific procedures, and treating common complications. This article utilizes key points for easy access of important messages and authors’ recommendation based on the authors’ clinical experiences.
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Affiliation(s)
- Kaela L Navarro
- Department of Comparative Medicine, Stanford University, Stanford, California, USA
| | - Monika Huss
- Department of Comparative Medicine, Stanford University, Stanford, California, USA
| | - Jennifer C Smith
- Bioresources Department, Henry Ford Health System, Detroit, Michigan, USA
| | - Patrick Sharp
- Office of Research and Economic Development, University of California, Merced, California, USA
- Animal Resources Authority, Murdoch, Australia
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - James O Marx
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cholawat Pacharinsak
- Corresponding Author: Cholawat Pacharinsak, DVM, PhD, DACVAA, Stanford University, Department of Comparative Medicine, 287 Campus Drive, Stanford, CA 94305-5410, USA. E-mail:
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Abstract
PRACTICAL RELEVANCE Procedural sedation and analgesia (PSA) describes the process of depressing a patient's conscious state to perform unpleasant, minimally invasive procedures, and is part of the daily routine in feline medicine. Maintaining cardiopulmonary stability is critical while peforming PSA. CLINICAL CHALLENGES Decision-making with respect to drug choice and dosage regimen, taking into consideration the cat's health status, behavior, any concomitant diseases and the need for analgesia, represents an everyday challenge in feline practice. While PSA is commonly perceived to be an uneventful procedure, complications may arise, especially when cats that were meant to be sedated are actually anesthetized. AIMS This clinical article reviews key aspects of PSA in cats while exploring the literature and discussing complications and risk factors. Recommendations are given for patient assessment and preparation, clinical monitoring and fasting protocols, and there is discussion of how PSA protocols may change blood results and diagnostic tests. An overview of, and rationale for, building a PSA protocol, and the advantages and disadvantages of different classes of sedatives and anesthetics, is presented in a clinical context. Finally, injectable drug protocols are reported, supported by an evidence-based approach and clinical experience.
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Affiliation(s)
- Bradley T Simon
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Paulo V Steagall
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Universite de Montreal, Saint-Hyacinthe, Canada
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Li CX, Kempf D, Howell L, Zhang X. Effects of alfaxalone on cerebral blood flow and intrinsic neural activity of rhesus monkeys: A comparison study with ketamine. Magn Reson Imaging 2020; 75:134-140. [PMID: 33127411 DOI: 10.1016/j.mri.2020.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Alfaxalone has been used increasingly in biomedical research and veterinary medicine of large animals in recent years. However, its effects on the cerebral blood flow (CBF) physiology and intrinsic neuronal activity of anesthetized brains remain poorly understood. METHODS Four healthy adult rhesus monkeys were anesthetized initially with alfaxalone (0.125 mg/kg/min) or ketamine (1.6 mg/kg/min) for 50 min, then administrated with 0.8% isoflurane for 60 min. Heart rates, breathing beats, and blood pressures were continuously monitored. CBF data were collected using pseudo-continuous arterial spin-labeling (pCASL) MRI technique and rsfMRI data were collected using single-shot EPI sequence for each anesthetic. RESULTS Both the heart rates and mean arterial pressure (MAP) remained more stable during alfaxalone infusion than those during ketamine administration. Alfaxalone reduced CBF substantially compared to ketamine anesthesia (grey matter, 65 ± 22 vs. 179 ± 38 ml/100g/min, p<0.001; white matter, 14 ± 7 vs. 26 ± 6 ml/100g/min, p < 0.05); In addition, CBF increase was seen in all selected cortical and subcortical regions of alfaxalone-pretreated monkey brains during isoflurane exposure, very different from the findings in isoflurane-exposed monkeys pretreated with ketamine. Also, alfaxalone showed suppression effects on functional connectivity of the monkey brain similar to ketamine. CONCLUSION Alfaxalone showed strong suppression effects on CBF of the monkey brain.The residual effect of alfaxalone on CBF of isoflurane-exposed brains was evident and monotonous in all the examined brain regions when used as induction agent for inhalational anesthesia. In particular, alfaxalone showed similar suppression effect on intrinsic neuronal activity of the brain in comparison with ketamine. These findings suggest alfaxalone can be a good alternative to veterinary anesthesia in neuroimaging examination of large animal models. However, its effects on CBF and functional connectivity should be considered.
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Affiliation(s)
- Chun-Xia Li
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Doty Kempf
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Leonard Howell
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Xiaodong Zhang
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States.
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Lervik A, Toverud SF, Krontveit R, Haga HA. A comparison of respiratory function in pigs anaesthetised by propofol or alfaxalone in combination with dexmedetomidine and ketamine. Acta Vet Scand 2020; 62:14. [PMID: 32164761 PMCID: PMC7066810 DOI: 10.1186/s13028-020-0512-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/29/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND General anaesthesia in pigs maintained with intravenous drugs such as propofol may cause respiratory depression. Alfaxalone gives less respiratory depression than propofol in some species. The aim of the investigation was to compare respiratory effects of propofol-ketamine-dexmedetomidine and alfaxalone-ketamine-dexmedetomidine in pigs. Sixteen pigs premedicated with ketamine 15 mg/kg and midazolam 1 mg/kg intramuscularly were anaesthetised with propofol or alfaxalone to allow endotracheal intubation, followed by propofol 8 mg/kg/h or alfaxalone 5 mg/kg/h in combination with ketamine 5 mg/kg/h and dexmedetomidine 4 µg/kg/h given as a continuous infusion for 60 min. The pigs breathed spontaneously with an FIO2 of 0.21. Oxygen saturation (SpO2), end-tidal CO2 concentration (PE'CO2), respiratory rate (fR) and inspired tidal volume (VT) were measured, and statistically compared between treatments. If the SpO2 dropped below 80% or if PE'CO2 increased above 10.0 kPa, the pigs were recorded as failing to complete the study, and time to failure was statistically compared between treatments. RESULTS Alfaxalone treated pigs had significantly higher respiratory rates and lower PE'CO2 than propofol treated pigs, with a fR being 7.3 /min higher (P = 0.01) and PE'CO2 0.8 kPa lower (P = 0.05). SpO2 decreased by 0.6% and fR by 1.0 /min per kg increase in body weight in both treatment groups. Three of eight propofol treated and two of eight alfaxalone treated pigs failed to complete the study, and times to failure were not significantly different between treatments (P = 0.75). CONCLUSIONS No major differences in respiratory variables were found when comparing treatments. Respiratory supportive measures must be available when using both protocols.
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Antkowiak B, Rammes G. GABA(A) receptor-targeted drug development -New perspectives in perioperative anesthesia. Expert Opin Drug Discov 2019; 14:683-699. [DOI: 10.1080/17460441.2019.1599356] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Bernd Antkowiak
- Department of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, Eberhard-Karls-University,
Tübingen, Germany
- Department of Anaesthesiology and Intensive Care, Experimental Anaesthesiology Section, Werner Reichardt Center for Integrative Neuroscience, Tübingen,
Germany
| | - Gerhard Rammes
- University Hospital rechts der Isar, Department of Anesthesiology, München,
Germany
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Hampton CE, Riebold TW, LeBlanc NL, Scollan KF, Mandsager RE, Sisson DD. Effects of intravenous administration of tiletamine-zolazepam, alfaxalone, ketamine-diazepam, and propofol for induction of anesthesia on cardiorespiratory and metabolic variables in healthy dogs before and during anesthesia maintained with isoflurane. Am J Vet Res 2019; 80:33-44. [PMID: 30605029 DOI: 10.2460/ajvr.80.1.33] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare effects of tiletamine-zolazepam, alfaxalone, ketamine-diazepam, and propofol for anesthetic induction on cardiorespiratory and acid-base variables before and during isoflurane-maintained anesthesia in healthy dogs. ANIMALS 6 dogs. PROCEDURES Dogs were anesthetized with sevoflurane and instrumented. After dogs recovered from anesthesia, baseline values for cardiorespiratory variables and cardiac output were determined, and arterial and mixed-venous blood samples were obtained. Tiletamine-zolazepam (5 mg/kg), alfaxalone (4 mg/kg), propofol (6 mg/kg), or ketamine-diazepam (7 and 0.3 mg/kg) was administered IV in 25% increments to enable intubation. After induction (M0) and at 10, 20, 40, and 60 minutes of a light anesthetic plane maintained with isoflurane, measurements and sample collections were repeated. Cardiorespiratory and acid-base variables were compared with a repeated-measures ANOVA and post hoc t test and between time points with a pairwise Tukey test. RESULTS Mean ± SD intubation doses were 3.8 ± 0.8 mg/kg for tiletamine-zolazepam, 2.8 ± 0.3 mg/kg for alfaxalone, 6.1 ± 0.9 mg/kg and 0.26 ± 0.04 mg/kg for ketamine-diazepam, and 5.4 ± 1.1 mg/kg for propofol. Anesthetic depth was similar among regimens. At M0, heart rate increased by 94.9%, 74.7%, and 54.3% for tiletamine-zolazepam, ketamine-diazepam, and alfaxalone, respectively. Tiletamine-zolazepam caused higher oxygen delivery than propofol. Postinduction apnea occurred in 3 dogs when receiving alfaxalone. Acid-base variables remained within reference limits. CONCLUSIONS AND CLINICAL RELEVANCE In healthy dogs in which a light plane of anesthesia was maintained with isoflurane, cardiovascular and metabolic effects after induction with tiletamine-zolazepam were comparable to those after induction with alfaxalone and ketamine-diazepam.
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Lagos-Carvajal A, Queiroz-Williams P, da Cunha A, Liu CC. Determination of midazolam dose for co-induction with alfaxalone in sedated cats. Vet Anaesth Analg 2019; 46:299-307. [PMID: 30928240 DOI: 10.1016/j.vaa.2019.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 12/23/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate the median effective dose 50 (ED50) of midazolam required for endotracheal intubation when used for co-induction of anesthesia with a low dose of alfaxalone in sedated cats. STUDY DESIGN Randomized up-and-down study. ANIMALS A group of 14 mixed-breed cats (eight males, six females), aged 5-12 years and weighing 4.4-6.8 kg. METHODS The cats were randomly assigned in a sequential allocation numbers from one to 14. Cats were sedated with dexmedetomidine (3 μg kg-1) and methadone (0.3 mg kg-1) intramuscularly. After 15 minutes, the quality of sedation was subjectively evaluated. Anesthesia induction was performed by intravenous (IV) administration of alfaxalone (0.25 mg kg-1) over a 60 second interval, followed by another 60 second interval, and then an IV dose of midazolam was administered over a 5 second interval. The initial midazolam dose was 0.3 mg kg-1; then, the midazolam dose was adjusted by ±0.1 mg kg-1 for each consecutive cat based on successful or unsuccessful endotracheal intubation of the previous animal following an up-and-down method. This sequence was followed until six nonsequential crossovers were observed. Crossover was defined as two opposite outcomes in two sequential animals. Data were analyzed using isotonic regression with bootstrapping for determination of midazolam ED50 and logistic regression for correlations (p < 0.05). RESULTS Overall, six independent crossovers were found, and ED50 of midazolam was 0.08 ± 0.04 mg kg-1. Sedation score and successful tracheal intubation had a strong positive correlation (p = 0.02). CONCLUSIONS AND CLINICAL RELEVANCE This study determined that 0.08 ± 0.04 mg kg-1 of midazolam co-administered with 0.25 mg kg-1 of alfaxalone IV allowed smooth endotracheal intubation in half of the cats sedated with methadone and dexmedetomidine at the doses used in this study.
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Affiliation(s)
- Angie Lagos-Carvajal
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Patricia Queiroz-Williams
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
| | - Anderson da Cunha
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Chin-Chi Liu
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
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Wu B, Jayakar SS, Zhou X, Titterton K, Chiara DC, Szabo AL, Savechenkov PY, Kent DE, Cohen JB, Forman SA, Miller KW, Bruzik KS. Inhibitable photolabeling by neurosteroid diazirine analog in the β3-Subunit of human hetereopentameric type A GABA receptors. Eur J Med Chem 2018; 162:810-824. [PMID: 30544077 DOI: 10.1016/j.ejmech.2018.11.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/22/2022]
Abstract
Pregnanolone and allopregnanolone-type ligands exert general anesthetic, anticonvulsant and anxiolytic effects due to their positive modulatory interactions with the GABAA receptors in the brain. Binding sites for these neurosteroids have been recently identified at subunit interfaces in the transmembrane domain (TMD) of homomeric β3 GABAA receptors using photoaffinity labeling techniques, and in homomeric chimeric receptors containing GABAA receptor α subunit TMDs by crystallography. Steroid binding sites have yet to be determined in human, heteromeric, functionally reconstituted, full-length, glycosylated GABAA receptors. Here, we report on the synthesis and pharmacological characterization of several photoaffinity analogs of pregnanolone and allopregnanolone, of which 21-[4-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzoxy]allopregnanolone (21-pTFDBzox-AP) was the most potent ligand. It is a partial positive modulator of the human α1β3 and α1β3γ2L GABAA receptors at sub-micromolar concentrations. [3H]21-pTFDBzox-AP photoincorporated in a pharmacologically specific manner into the α and β subunits of those receptors, with the β3 subunit photolabeled most efficiently. Importantly, photolabeling by [3H]21-pTFDBzox-AP was inhibited by the positive steroid modulators alphaxalone, pregnanolone and allopregnanolone, but not by inhibitory neurosteroid pregnenolone sulfate or by two potent general anesthetics and GABAAR positive allosteric modulators, etomidate and an anesthetic barbiturate. The latter two ligands bind to sites at subunit interfaces in the GABAAR that are different from those interacting with neurosteroids. 21-pTFDBzox-AP's potency and pharmacological specificity of photolabeling indicate its suitability for characterizing neurosteroid binding sites in native GABAA receptors.
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Affiliation(s)
- Bo Wu
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL, 60612, USA
| | - Selwyn S Jayakar
- Department of Neurobiology, 220 Longwood Avenue, Harvard Medical School, Boston, MA, 02115, USA
| | - Xiaojuan Zhou
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA, 02114, USA
| | - Katherine Titterton
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA, 02114, USA
| | - David C Chiara
- Department of Neurobiology, 220 Longwood Avenue, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrea L Szabo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA, 02114, USA
| | - Pavel Y Savechenkov
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL, 60612, USA
| | - Daniel E Kent
- Department of Health Science, Northeastern University, 360 Huntington Ave, Boston, MA, 02115, USA
| | - Jonathan B Cohen
- Department of Neurobiology, 220 Longwood Avenue, Harvard Medical School, Boston, MA, 02115, USA
| | - Stuart A Forman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA, 02114, USA
| | - Keith W Miller
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA, 02114, USA; Department of Biological Chemistry and Molecular Pharmacology, 220 Longwood Avenue, Harvard Medical School, Boston, MA, 02115, USA
| | - Karol S Bruzik
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL, 60612, USA.
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Pharmacokinetics of intramuscular alfaxalone and its echocardiographic, cardiopulmonary and sedative effects in healthy dogs. PLoS One 2018; 13:e0204553. [PMID: 30248146 PMCID: PMC6152991 DOI: 10.1371/journal.pone.0204553] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 08/17/2018] [Indexed: 11/19/2022] Open
Abstract
The pharmacokinetics and the effects of a single intramuscular (IM) dose of alfaxalone on sedation and cardiopulmonary and echocardiographic variables was studied in dogs. Twelve healthy adult Beagles (3 females, 9 males) were used in this prospective controlled cross-over trial. Echocardiography was performed with and without 4 mg kg-1 alfaxalone IM with a week wash-out interval. Sedation (19-point scale; 0 = no sedation), cardiopulmonary parameters, blood gas analysis and plasma concentration of alfaxalone were assessed every 5 minutes following the injection (T0). The influence of the alfaxalone plasma concentration and time on physiological variables was tested using a linear model whereas echocardiographic measurements were compared between conscious and alfaxalone-administered dogs using paired t-tests. Compared to baseline, alfaxalone administration was followed by an increase in heart rate (HR) from T5 to T30 and a decrease in mean arterial pressure (MAP) at T10, T25 and T30, in stroke volume (SV; 15 ± 5 to 11 ± 3 ml; P<0.0001), and end-diastolic volume (EDV; 24.7 ± 5.7 to 19.4 ± 4.9 ml). Cardiac output (CO) and blood gas analysis did not change significantly throughout. Mean plasma half-life was 29 ± 8 minutes, volume of distribution was 1.94 ± 0.63 L kg-1, and plasma clearance was 47.7 ± 14.1 ml kg-1 minute-1. Moderate to deep sedation was observed from T5 to T35. Ten dogs showed paddling, trembling, nystagmus and strong reaction to sound during the procedure. Although there were no significant changes in CO and oxygenation, the impact of HR, MAP, SV, EDV alterations requires further investigations in dogs with cardiac disease.
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Pasloske K, Ranasinghe MG, Sauer S, Hare J. The bioequivalence of a single intravenous administration of the anesthetic alfaxalone in cyclodextrin versus alfaxalone in cyclodextrin plus preservatives in cats. J Vet Pharmacol Ther 2018; 41:437-446. [PMID: 29352472 DOI: 10.1111/jvp.12485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/14/2017] [Indexed: 11/26/2022]
Abstract
To demonstrate the bioequivalence of alfaxalone in cyclodextrin (Reference Product) to a formulation of alfaxalone in cyclodextrin also containing the preservatives ethanol, chlorocresol, and benzethonium chloride (Test Product) when administered for the purpose of inducing anesthesia in the cat. Blinded, single-dose, randomized, two-period, two-sequence, cross-over bioequivalence study with a 7-day washout period between treatments. Twenty-four (12 neutered males and 12 intact females), healthy, adult cats weighing 4.1±0.9 kg. Cats were administered 5 mg/kg IV of alfaxalone in the Reference or Test Product using a randomized cross-over design. One-milliliter venous blood samples were collected at predetermined time points to 12 hr after drug administration to determine alfaxalone plasma concentration over time. Alfaxalone concentrations were determined by a validated analytical testing method using HPLC-MS/MS. Plasma profiles of alfaxalone concentration against time were analyzed by noncompartmental analysis. The pivotal variables for bioequivalence were AUClast and Cmax . Equivalence was achieved if the 90% confidence interval for AUClast and Cmax fell into the asymmetric ±20% interval (0.80-1.25). Physiological variables, quality of anesthesia visual analog scale (VAS) scoring and anesthetic event times were recorded. ANOVA or ANCOVA (single time point), RMANOVA or RMANCOVA (multiple time point) was used for normally distributed data. GLIMMIX was used for nonnormally distributed data. VAS scores were analyzed as for blood bioequivalence data. Variables were evaluated for safety and assessed at alpha = 0.10. Cmax and AUClast for Reference and Test Products were statistically bioequivalent. No physiological variables except for a drug by time interaction for respiratory rate differed between treatment groups, and this difference was not clinically relevant. No anesthetic event times or VAS scores for quality of anesthesia were different between treatment groups. Neither formulation caused pain upon injection. The Reference and Test Products are pharmaceutically bioequivalent formulations when administered as a single intravenous administration for the purpose of induction of anesthesia in cats.
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Affiliation(s)
- K Pasloske
- Jurox Pty. Ltd., Rutherford, NSW, Australia
| | | | - S Sauer
- Jurox Pty. Ltd., Rutherford, NSW, Australia
| | - J Hare
- Kingfisher International Inc., Stouffville, ON, Canada
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14
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Muñoz KA, Robertson SA, Wilson DV. Alfaxalone alone or combined with midazolam or ketamine in dogs: intubation dose and select physiologic effects. Vet Anaesth Analg 2017; 44:766-774. [PMID: 28756063 DOI: 10.1016/j.vaa.2017.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To determine the intubation dose and select physiologic effects of alfaxalone alone or in combination with midazolam or ketamine in dogs. STUDY DESIGN Prospective, clinical study. ANIMALS Fifty-three healthy client-owned dogs [mean±standard deviation (SD)] 5.1±1.8 years, 27±15.4 kg, scheduled for elective orthopedic surgery. METHODS After premedication with acepromazine (0.02 mg kg-1) and hydromorphone (0.1 mg kg-1) intramuscularly, alfaxalone (0.25 mg kg-1) was administered intravenously over 15 seconds followed immediately by 0.9% saline (AS), midazolam (0.3 mg kg-1; AM), ketamine (1 mg kg-1; AK1), or ketamine (2 mg kg-1; AK2). Additional alfaxalone (0.25 mg kg-1 increments) was administered as required to permit endotracheal intubation. The incidence of apnea and the time from intubation until spontaneous movement were recorded. Heart rate (HR) and blood pressure were recorded 15 minutes after premedication, after intubation and 2, 5, 10 and 15 minutes thereafter. Blood was collected for measurement of serum glucose and insulin concentrations before induction, after intubation and at 2, 5, 10 and 50 minutes. Data were analyzed by split-plot anova with Bonferroni adjustment for the number of group comparisons. RESULTS Mean±SD alfaxalone mg kg-1 doses required for endotracheal intubation were AS (1.0±0.4), AM (0.4±0.2), AK1 (0.5±0.3) and AK2 (0.5±0.4) (p=0.0005). Differences in cardiopulmonary variables among groups were minor; HR decreased in AS, while in other groups, HR increased transiently postintubation. Incidence of apnea in AS was 54% with no significant difference among groups. Midazolam significantly prolonged time from intubation until spontaneous movement (p<0.002). CONCLUSIONS AND CLINICAL RELEVANCE Midazolam and ketamine reduced the alfaxalone dose required for endotracheal intubation. Serum glucose and insulin concentrations were not influenced by administration of alfaxalone alone or when administered with midazolam or ketamine.
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Affiliation(s)
- Kirk A Muñoz
- Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA.
| | - Sheilah A Robertson
- Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Deborah V Wilson
- Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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