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Home / Equine Research Bank / Vet Anaesth Analg / The pharmacokinetics and pharmacodynamics of the injectable ...
Veterinary anaesthesia and analgesia2011; 38(5); 431-438; doi: 10.1111/j.1467-2995.2011.00634.x

The pharmacokinetics and pharmacodynamics of the injectable anaesthetic alfaxalone in the horse.

Abstract: To determine the pharmacokinetics and pharmacodynamics of the neurosteroidal anaesthetic, alfaxalone, in horses after a single intravenous (IV) injection of alfaxalone, following premedication with acepromazine, xylazine and guaiphenesin. Methods: Prospective experimental study. Methods: Ten (five male and five female), adult, healthy, Standardbred horses. Methods: Horses were premedicated with acepromazine (0.03 mg kg(-1) IV). Twenty minutes later they received xylazine (1 mg kg(-1) IV), then after 5 minutes, guaiphenesin (35 mg kg(-1) IV) followed immediately by IV induction of anaesthesia with alfaxalone (1 mg kg(-1) ). Cardiorespiratory variables (pulse rate, respiratory rate, pulse oximetry) and clinical signs of anaesthetic depth were evaluated throughout anaesthesia. Venous blood samples were collected at strategic time points and plasma concentrations of alfaxalone were assayed using liquid chromatography-mass spectrometry (LC/MS) and analysed by noncompartmental pharmacokinetic analysis. The quality of anaesthetic induction and recovery was scored on a scale of 1-5 (1 very poor, 5 excellent). Results: The median (range) induction and recovery scores were 4 (3-5) (good: horse slowly and moderately gently attained recumbency with minimal or no rigidity or paddling) and 4 (1-5) (good: horse stood on first attempt with some knuckling and ataxia) respectively. The monitored cardiopulmonary variables were within the range expected for clinical equine anaesthesia. The mean ± SD durations of anaesthesia from induction to sternal recumbency and from induction to standing were 42.7 ± 8.4 and 47 ± 9.6 minutes, respectively. The mean ± SD plasma elimination half life (t(1/2) ), plasma clearance (Clp) and volume of distribution (V(d) ) for alfaxalone were 33.4 minutes, 37.1 ± 11.1 mL minute(-1)  kg(-1) and 1.6 ± 0.4 L kg(-1) , respectively. Conclusions: Alfaxalone, in a 2-hydroxypropyl-beta-cyclodextrin formulation, provides anaesthesia with a short duration of recumbency that is characterised by a smooth induction and satisfactory recovery in the horse. As in other species, alfaxalone is rapidly cleared from the plasma in the horse.
© 2011 The Authors. Veterinary Anaesthesia and Analgesia. © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.
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Publication Date: 2011-08-13 PubMed ID: 21831048DOI: 10.1111/j.1467-2995.2011.00634.xGoogle Scholar: Lookup
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Summary

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This research article investigates the pharmacokinetics (how the body processes a drug) and pharmacodynamics (the effects the drug has on the body) of alfaxalone. The study uses healthy, adult horses that were premedicated and then given an intravenous dose of alfaxalone. The researchers monitored the horses’ cardiorespiratory variables and evaluated their anaesthetic depth. Blood samples were also taken and analysed so as to determine alfaxalone concentrations.

Experiment Procedure

  • The experimental study was carried out on ten adult, Standardbred horses (five male and five female).
  • Before the anaesthetic (alfaxalone) was administered, the horses were given premedication, which consisted of acepromazine, xylazine, and guaiphenesin.
  • Cardiorespiratory variables like the pulse rate, respiratory rate, and pulse oximetry were monitored and recorded continuously during the anaesthesia duration.
  • Venous blood samples were taken at specific intervals or time points and analysed to measure alfaxalone concentrations, using a method referred to as liquid chromatography-mass spectrometry (LC/MS).
  • Anaesthetic induction and recovery was evaluated on a scale of 1-5, where 1 was very poor and 5 was excellent.

Results of the Study

  • The horses typically demonstrated good induction and recovery, with median scores of 4 on the 1-5 scale.
  • Cardiorespiratory variables remained within the acceptable and expected range for equine anaesthesia.
  • The average duration of anaesthesia (from induction to the horse regaining an upright position) was approximately 47 minutes. The recumbency duration (from induction until the horses lie sternal) was roughly 43 minutes.
  • The pharmacokinetic properties of alfaxalone were determined: it had a plasma elimination half-life of about 33.4 minutes, a plasma clearance rate of 37.1 mL per minute per kg, and a volume of distribution of about 1.6 L/kg.

Conclusions Drawn from the Study

  • Alfaxalone in a 2-hydroxypropyl-beta-cyclodextrin formulation could be a viable option for equine anaesthesia, providing a smooth induction, short recumbency duration, and satisfactory recovery.
  • Similar to its behaviour in other animal species, alfaxalone was observed to be rapidly cleared from the horse’s plasma.

Cite This Article

APA
Goodwin WA, Keates HL, Pasloske K, Pearson M, Sauer B, Ranasinghe MG. (2011). The pharmacokinetics and pharmacodynamics of the injectable anaesthetic alfaxalone in the horse. Vet Anaesth Analg, 38(5), 431-438. https://doi.org/10.1111/j.1467-2995.2011.00634.x

Publication

Veterinary anaesthesia and analgesia
ISSN: 1467-2995
NlmUniqueID: 100956422
Country: United States
Language: English
Volume: 38
Issue: 5
Pages: 431-438

Researcher Affiliations

Goodwin, Wendy A
  • School of Veterinary Science, University of Queensland, Brisbane, Qld, Australia. w.goodwin@uq.edu.au
Keates, Helen L
    Pasloske, Kirby
      Pearson, Martin
        Sauer, Ben
          Ranasinghe, Millaganamada Gedara

            MeSH Terms

            • Anesthesia, Intravenous / methods
            • Anesthesia, Intravenous / veterinary
            • Anesthetics, Intravenous / pharmacokinetics
            • Anesthetics, Intravenous / pharmacology
            • Animals
            • Female
            • Guaifenesin
            • Heart Rate / drug effects
            • Hemoglobins / analysis
            • Horses
            • Hypnotics and Sedatives
            • Injections, Intravenous / veterinary
            • Male
            • Pregnanediones / blood
            • Pregnanediones / pharmacokinetics
            • Pregnanediones / pharmacology
            • Respiratory Rate / drug effects
            • Xylazine

            Citations

            This article has been cited 15 times.
            1. Daskalaki M, Drummer C, Behr R, Heistermann M. The use of alfaxalone for short-term anesthesia can confound serum progesterone measurements in the common marmoset: a case report. Primate Biol 2022;9(2):23-28.
              doi: 10.5194/pb-9-23-2022pubmed: 36034474google scholar: lookup
            2. Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature. Animals (Basel) 2021 Jun 14;11(6).
              doi: 10.3390/ani11061777pubmed: 34198637google scholar: lookup
            3. Abouelfetouh MM, Liu L, Salah E, Sun R, Nan S, Ding M, Ding Y. The Effect of Xylazine Premedication on the Dose and Quality of Anesthesia Induction with Alfaxalone in Goats. Animals (Basel) 2021 Mar 6;11(3).
              doi: 10.3390/ani11030723pubmed: 33800906google scholar: lookup
            4. Tsukamoto Y, Yamada N, Miyoshi K, Yamashita K, Ohsugi T. Anesthetic effect of a mixture of alfaxalone, medetomidine, and butorphanol for inducing surgical anesthesia in ICR, BALB/c, and C57BL/6 mouse strains. J Vet Med Sci 2019 Jun 28;81(6):937-945.
              doi: 10.1292/jvms.18-0712pubmed: 31080189google scholar: lookup
            5. Lau C, Thakre PP, Bellingham MC. Alfaxalone Causes Reduction of Glycinergic IPSCs, but Not Glutamatergic EPSCs, and Activates a Depolarizing Current in Rat Hypoglossal Motor Neurons. Front Cell Neurosci 2019;13:100.
              doi: 10.3389/fncel.2019.00100pubmed: 30967762google scholar: lookup
            6. Tokushige H, Kushiro A, Okano A, Maeda T, Ito H, Wakuno A, Nagata SI, Ohta M. Clinical evaluation of constant rate infusion of alfaxalone-medetomidine combined with sevoflurane anesthesia in Thoroughbred racehorses undergoing arthroscopic surgery. Acta Vet Scand 2018 Sep 4;60(1):50.
              doi: 10.1186/s13028-018-0406-4pubmed: 30180855google scholar: lookup
            7. El-Hawari SF, Sakata H, Oyama N, Tamura J, Higuchi C, Endo Y, Miyoshi K, Sano T, Suzuki K, Yamashita K. Anesthetic and cardiorespiratory effects of single-bolus intravenous alfaxalone with or without intramuscular xylazine-premedication in calves. J Vet Med Sci 2018 Mar 2;80(2):361-367.
              doi: 10.1292/jvms.17-0512pubmed: 29269688google scholar: lookup
            8. Aoki M, Wakuno A, Kushiro A, Mae N, Kakizaki M, Nagata SI, Ohta M. Evaluation of total intravenous anesthesia with propofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in Thoroughbred horses undergoing castration. J Vet Med Sci 2017 Dec 22;79(12):2011-2018.
              doi: 10.1292/jvms.16-0658pubmed: 29057764google scholar: lookup
            9. Wakuno A, Maeda T, Kodaira K, Kikuchi T, Ohta M. Anesthetic management with sevoflurane combined with alfaxalone-medetomidine constant rate infusion in a Thoroughbred racehorse undergoing a long-time orthopedic surgery. J Equine Sci 2017;28(3):111-115.
              doi: 10.1294/jes.28.111pubmed: 28955163google scholar: lookup
            10. Ansel TV, Nour AK, Benavente-Perez A. The Effect of Anesthesia on Blood Pressure Measured Noninvasively by Using the Tail-Cuff Method in Marmosets (Callithrix jacchus). J Am Assoc Lab Anim Sci 2016;55(5):594-600.
              pubmed: 27657716
            11. Siriarchavatana P, Ayers JD, Kendall LV. Anesthetic Activity of Alfaxalone Compared with Ketamine in Mice. J Am Assoc Lab Anim Sci 2016;55(4):426-30.
              pubmed: 27423149
            12. Ohmura H, Okano A, Mukai K, Fukuda K, Takahashi T. Cardiorespiratory and anesthetic effects of combined alfaxalone, butorphanol, and medetomidine in Thoroughbred horses. J Equine Sci 2016;27(1):7-11.
              doi: 10.1294/jes.27.7pubmed: 27073330google scholar: lookup
            13. Di Stefano D, Suganthan H, Buck L. Alfaxalone does not have long-term effects on goldfish pyramidal neuron action potential properties or GABA(A) receptor currents. FEBS Open Bio 2024 Apr;14(4):555-573.
              doi: 10.1002/2211-5463.13777pubmed: 38342633google scholar: lookup
            14. Fernández Castañer J, Quirós Carmona S, Martínez Bernal C, Morgaz Rodríguez J, Navarrete Calvo R, Granados Machuca MDM. Sedation Quality and Cardiorespiratory, Echocardiographic, Radiographic and Electrocardiographic Effects of Intramuscular Alfaxalone and Butorphanol in Spanish Greyhound Dogs. Animals (Basel) 2023 Sep 16;13(18).
              doi: 10.3390/ani13182937pubmed: 37760337google scholar: lookup
            15. Beths T, Touzot-Jourde G, Musk G, Pasloske K. Clinical evaluation of alfaxalone to induce and maintain anaesthesia in cats undergoing neutering procedures. J Feline Med Surg 2014 Aug;16(8):609-15.
              doi: 10.1177/1098612X13514420pubmed: 24305470google scholar: lookup
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